Innovation Spotlight: How DOTs Are Moving Toward Digital As-Builts

Posted on September 6, 2021September 6, 2021

The FHWA is promoting the deployment of Digital As-Builts (DABs) in Round 6 of the Every Day Counts (EDC-6) Program. FHWA defines DABs as an accumulation of the data used during digital project delivery that provides a living record of built infrastructure for agencies’ future business needs. The latest FHWA Innovator, September/October, Issue 86, features a section on e-Ticketing and Digital As Builts that briefly defines the innovation and its benefits along with a short video of digital delivery efforts at Utah DOT.

During EDC-6, the NJ STIC has set forward goals for advancing Digital As-Builts, assessing the current stage of innovation as “development” and setting forward some near-term capacity-building actions.

This article reports on a brief Digital As-Builts Literature Scan and provides references to a select bibliography of research reports, strategic plans and other resource documents that may warrant closer inspection for innovation teams. The literature scan identifies some key definitions, benefits, emerging practices, recurring challenges and possible lessons when taking steps toward deployment of DABs.

Digital As-Builts Literature Scan

Introduction

A Digital As-Built (DAB) innovates by transferring what are typically 2D, paper records into digital, three-dimensional (3D) datafiles that can be regularly updated and shared with stakeholders throughout a project’s life cycle. This information becomes invaluable in the asset management and operations phase, in which it is crucial for agencies to have the most current, comprehensive data covering their facility’s construction. DABs can also be referred to as digital twins, intricate computerized copies of a road or bridge that simulate real-time conditions, allowing for predictive maintenance and more cost-effective mitigation projects.

Across the country, state departments of transportation (state DOTs) are beginning to adopt DABs requirements for future road and bridge projects. The Pennsylvania Department of Transportation (PennDOT), for instance, has established ambitious agency goals that by 2035, all agency projects will be bid upon using 3D models—which will be updated throughout the project’s development through completion, and then stored in a centralized database (PennDOT, 2020).

While industry standard software and practices are still emerging, the research, experiences, and challenges from DOTs nationwide can assist in the identification of promising practices and planning the transition to DABs.

Benefits of Digital As-Builts

Digital As-Builts are digitized, detailed records of completed construction projects. These could encapsulate roadways, bridges, barriers, berms, and any other facilities. What is revolutionary about DABs is their capacity to be used as digital twins, sophisticated mock-ups of the actual structure that enable agencies to streamline maintenance and improvement projects. DABs are simple to store and distribute, reducing the time and material costs from producing traditional 2D as-builts. Created using Computer Aided Drafting and Design (CADD) software, and updated with real-world readings, such as laser-based LiDAR, DABs are versatile and, increasingly, trustworthy records.

DABs were selected as part of the FHWA’s EDC-6, featured for their advances in safety, time savings, and quality (FHWA, 2021). In addition to providing high quality records that can optimize maintenance and asset management, DABs can streamline the project development process by easily showing decision makers the location of existing infrastructure. The safety benefits come, in part, from shorter work interruptions of regular traffic flows.

DABs offer the capability to reliably retain information throughout the project process, as data is handed over from one department agency to another. A UC-Davis report, conducted on behalf of the California Department of Transportation (Caltrans), suggests that DABs can reduce the risk of lost information considerably (Advanced Highway Maintenance and Construction Technology Research Center, 2020). Another report, prepared for the Kentucky Transportation Cabinet (KYTC) by University of Kentucky researchers, found that digital documentation could significantly build trust in as-built records. In 2018, KYTC spent $217,000 on new forensic investigations because handmade, paper as-builts were deemed untrustworthy (Kentucky Transportation Center, 2019). But DABs, especially when well-updated and held to high standards of detail, can reduce the need for new surveys and ultimately lower costs.

DABs feed into an integrated workflow in which completed facility information is readily accessible for asset management and maintenance. This process is an element of Civil Integrated Management (CIM), and involves the entire lifecycle of a facility.

Existing Practices

Though many aspects of life have been affected by increasing digitization, the as-built record-keeping process in state transportation remains rooted in the analog era. It was apparent, from the literature reviewed, that the majority of state transportation departments are still using 2D, paper as-builts for facility specifications.

When DABs were being used, they were as pilot projects to demonstrate their efficacy. Or, when a part of agency practice, as in the case of Caltrans, implementation was inconsistent and without sufficient coordination (AHMCTRC, 2020). Similarly, in Kentucky, some records were being stored digitally but without a designated central repository, or as hardcopies in a State Library and Archives warehouse for storage (KTC, 2019), offering little use for ongoing maintenance. States like Michigan and North Carolina, while looking to transition to digital records, were still working on their digital strategies and have yet to implement them as practice (FHWA, 2019).

Some states have recently established regulations requiring DABs, such as the Colorado Department of Transportation (CDOT), which updated the State Highway Utility Accommodation Code in 2021 calling for 3D subsurface models showing the location of utility lines in CDOT’s Right-of-Way (Colorado Department of Transportation, 2021). New York has established a 3D, 4D, and 5D requirement for certain megaprojects (such as the new Kosciuzko Bridge), that tie contractor payments to a continuously-updated model that is then revised with as-built information (FHWA, 2014). And Nevada, while requiring digital contract documents, has yet to add an as-built component. (Nevada Department of Transportation, 2021).

Many DOTs are being spurred to action by technological innovations and by prior EDC rounds (FHWA, 2015) and by the current FHWA’s EDC-6 e-Ticketing and Digital As-Builts initiative.

Emerging Practices

PennDOT appears at the leading edge in its development of a comprehensive DAB implementation plan, intending to adopt the digital delivery process as a department standard by 2025. For DABs, this involves a 5-year span spent developing standards and workflows for implementation. The planning process includes the functioning of various working groups for determining necessary infrastructure and modeling requirements, workspace needs, and training plans. Though PennDOT’s plan is still in progress, their Digital Delivery 2025 Strategic Plan offers a good example of a comprehensive, implementation document detailing steps the agency must take to make the transition to digital delivery (PennDOT, 2020).

Illusrates PenndDOT roadmap schedule for implementation of DABs

Figure 1: Sample Digital Delivery Roadmap from PennDOT.

Agencies in other states are also piloting new standards. Many DOTs are planning to convert from paper records, and to capitalize on this transition by taking advantage of the new digital records in the asset management process.

The Utah Department of Transportation of Transportation (UDOT) has created a website describing the benefits of digital delivery, including the advantages of the use of Digital Twins (UDOT, 2021). UDOT’s site also contains sample deliverables packages for contractors, with technical specifications for roadways, drainage, and structures viewable in Bentley ProjectWise, and document management software used for DABs by several DOTs (e.g., Virginia, Washington, Kentucky, and others) (Virginia Department of Transportation, 2019).

Virginia is also working to establish new guidelines to support the Civil Integrated Management (CIM) process. The guidelines will set standards for Level of Detail (LOD) for 3D renderings, as some models can be inconsistent. Because they are intended to exist as exact records of the constructed facility, DABs are required to be the highest LOD (Level 400) (Virginia Department of Transportation, 2020).

Michigan and North Carolina are currently transitioning from 2D plan sheets to 3D models of contractual documents (FHWA, 2019). Both states plan to incorporate the records into asset and operations management over the project’s lifecycle.

NYSDOT, for a bridge reconstruction in the Catskill region, developed a 3D model for a contract document using Bentley iTwin Design Review software (CS Engineer Magazine, 2021). After the bridge is completed, the contractor is obligated to upload as-built information to the 3D model. This approach is being piloted in New York, but is not yet adopted practice.

In Minnesota, the state Department of Transportation (MnDOT), adopted special as-built requirements for certain regions in the state, starting in the Minneapolis-St. Paul Metropolitan area (FHWA, 2019). The agency also has a dedicated website with DAB specifications. For example, a barrier as-built report might include latitudinal and longitudinal X, Y, and Z coordinates, as well as a Plan ID referring back to the plan set.

Nearby, Iowa DOT has begun using geo-equipped devices from ESRI to capture vector and asset attribute data during the construction process (Iowa DOT Research, 2021). The geolocated data captures the location and geometry of facilities, and is then uploaded to a Microsoft SQL server. As opposed to developing a 3D model in the design process, and then updating it with as-built conditions, an after-the-fact approach captures three-dimensional as-built data outside of the Building Information Modeling (BIM) process.

Other states are exploring how they might apply these concepts to how they manage the planning, design, construction, and maintenance of their facilities. The literature resources reviewed made the benefits of DABs abundantly clear, and showed considerable progress being made, but they also identified challenges in the full-scale deployment of Digital As-Builts as standard practice.

Challenges

Several of the resources reviewed identified barriers for DOTs for implementing DABs. For Developing a Strategic Roadmap for Caltrans Implementation of Virtual Design Construction/Civil Integrated Management (2020), researchers surveyed Caltrans employees from various departments to learn more about the obstacles that the department faced. Similarly, University of Kentucky researchers surveyed Kentucky Transportation Cabinet (KYTC) staff, in Redefining Construction As-Built Plans to Meet Current Kentucky Transportation Cabinet Needs (2019). FHWA has also prepared reports on innovative digital records practices at various states that detail various challenges (FHWA, 2019).

These reports reveal some recurring themes on the challenges experienced by state DOTs that can be broken into two axes — Workflow and Workforce — as well as some solutions to surmount them.

Table 1: Examples of Workflow and Workforce Challenges and Solutions to DABs Implementation

Axes	Challenges	Solutions	Examples
*Workflow*	Inconsistent Implementation	Develop robust, time-tested workflows	PennDOT
*Workflow*	Siloization	Facilitate interdepartmental coordination on projects and data updates	Caltrans
*Workflow*	Compatibility	Extensively test software workflows for technical errors, such as incompatibility	PennDOT
*Workflow*	Standards	Create file, format, and procedural standards (i.e. designated Levels of Detail). Require compatible software infrastructure to support DABs	PennDOT, UDOT, VDOT, NDOT, CDOT
*Workforce*	Digital Competencies	Educate employees with ongoing trainings that ease into DAB process	PennDOT
*Workforce*	Compliance	Educate for and enforce DAB protocols	UDOT, MnDOT

For example, the Caltrans report made clear that the development of an agency-wide workflow was paramount. Without one, various divisions were inconsistent and ineffective at capturing, maintaining, and communicating about DABs. Caltrans Roadway Design and Structures Design divisions fell short in updating and sharing the existence of updates with one another (AHMCTRC, 2020).

Regarding particular software, files, and workstations, care must be taken in the workflow design process to ensure compatibility. In Caltrans case, the Roadway Design and Structures Design divisions were using incompatible 3D modeling software. Iowa DOT experienced a similar issue, in which 3D, geolocated models created using ESRI software were then unable to be meaningfully edited in Bentley MicroStation (Iowa DOT Research, 2021). In addition, Iowa DOT’s 3D models, designed as part of a BIM process for a bridge girder replacement project, could not be edited because of the file type. An audit of Kentucky’s Transportation Cabinet found that, though there was a central repository for digital records (Bentley’s ProjectWise), files were uploaded inconsistently (KTC, 2019). While NYSDOT had planned, during the construction of the new Kosciusko Bridge, to continuously update a 3D model to show newly built components, they experienced severe network capacity constraints that prevented them from doing so (FHWA, 2014). Upfront planning, interdepartmental collaboration and testing ensures that DABs potential is unleashed.

The second tier of challenges arise from issues with workforce adoption. An FHWA case study looking at digital record keeping at MnDOT highlights difficulty with securing buy-in from construction staff to comply with new DAB requirements (FHWA, 2019). The KYTC study singled out a lack of digital competencies from older employees as one barrier towards adopting these new technologies. Change is difficult to implement, but especially when staff have become accustomed to the same practice for decades.

Recommendations

For Workflow design, a considered and deliberative process is required. Agencies must convene working groups of stakeholders and learn about department-specific concerns and established processes. Several years may be required to design new DAB workflows that maximize the potential of the new technology, and ensure that the infrastructure is in place to support and encourage staff to follow these workflows.

PennDOT’s plan for implementing digital delivery is an instructive and thorough model document on the subject (PennDOT, 2020). The agency’s Digital Delivery Strategic Plan breaks tasks down into actionable steps, such as Task 2.3, Post Construction Process and Procedures Development, scheduled from Q2-Q3 of 2021, which will map out new requirements and a plan to realize the new processes. An agency wishing to avoid siloization would do well to consult the UC-Davis study that provides itemized, exact solutions.

Figure 2: Another visual representation of PennDOT’s Digital Delivery Roadmap.

Architects of the new DAB workflow should be careful to promote interdepartmental collaboration, as well as select compatible software that supports such a goal. Bentley Systems design, engineering, and review software—MicroStation, OpenRoads, and ProjectWise, principally—appear to be the most consistently used across the country (AHMCTRC, 2020). For determining a cohesive workflow, it is imperative that varying software have compatibility with one another—and that they are consistently used across the department.

For the issue of designated detail levels, both Minnesota and Virginia have developed tables with standards specifying when and where to make DABs as accurate as possible, such as whether to survey the constructed facility at a detail of one foot or one meter (FHWA, 2019). The overall objective of the department may help to guide the development process: how does the agency aim to utilize BIM technology? A representative DAB could help to dramatically increase the efficiency of future maintenance or upgrade projects, but only if the appropriate standards are first put in place.

The Workforce presents complementary challenges and solutions. A technology is only useful if it is appropriately deployed—part of the workflow design process should include consultation with staff on specific barriers they face in their daily adoption of the technology. What might be preventing them from doing so? What types of trainings are required to achieve core competencies? Interviewing staff stakeholders will also help to determine accountability measures that could be put in place, for both staff and contractors, to help ensure consistent compliance with new workflows (KTC, 2019).

Moving Forward

Digital As-Builts are a promising technological innovation that can reduce inefficiencies in the life cycle of a transportation facility. If appropriately deployed, DABs can maximize the value of a project, eliminating the need for new forensic investigations, and retaining information as it is handed off from one phase to the next. Many of the DOTs surveyed are considering and incorporating innovative practices into their DAB implementation. Both Caltrans and KYTC, for example, are studying the use of laser-based scanning technologies to develop geolocated 3D models post-construction. In the coming years, as DABs are adopted into practice, more case studies will become available for reference.

From the resources reviewed, it was apparent that Digital As-Builts are promising technology that can streamline record-keeping and save transportation agencies both time and money.

Bibliography

Advanced Highway Maintenance and Construction Technology Research Center (2020). Developing a Strategic Roadmap for Caltrans Implementation of Virtual Design Construction/Civil Integrated Management. California Department of Transportation.https://dot.ca.gov/-/media/dot-media/programs/research-innovation-system-information/documents/final-reports/ca20-3178-finalreport-a11y.pdf

Colorado Department of Transportation. (2021). State Highway Utility Accommodation Code. Colorado Department of Transportation. https://www.sos.state.co.us/CCR/GenerateRulePdf.do?ruleVersionId=9244&fileName=2%20CCR%20601-18

CS Engineer Magazine. (2021). NYS DOT Delivers First Model-based Contracting 3D Project in Its History; Delivered the Project Under Budget and Restored a Critical Bridge to the Community. CS Engineer Magazine. https://csengineermag.com/nys-dot-delivers-first-model-based-contracting-3d-project-in-its-history-delivered-the-project-under-budget-and-restored-a-critical-bridge-to-the-community/

Federal Highway Administration. (2014). 4D and 5D Modeling: NYSDOT’s Approach to Optimizing Resources. Federal Highway Administration. https://www.fhwa.dot.gov/construction/3d/hif16024.pdf

Federal Highway Administration. (2015). 3D Engineered Models: Schedule, Cost and Post-Construction: Fact Sheet. https://www.fhwa.dot.gov/innovation/pdfs/factsheets/edc/edc-3_factsheet_3d_engineered_models.pdf

Federal Highway Administration (2021). e-Ticketing and Digital As-Builts. Federal Highway Administration. https://www.fhwa.dot.gov/innovation/everydaycounts/edc_6/eticketing.cfm

Federal Highway Administration. (2019). Michigan DOT Digital Delivery Working Group. Federal Highway Administration. https://www.fhwa.dot.gov/construction/econstruction/edc4/hif19033.pdf

Federal Highway Administration. (2019). Minnesota and Iowa DOT Solutions for Capturing Asset Information During Construction. Federal Highway Administration.https://www.fhwa.dot.gov/construction/econstruction/hif19075.pdf

Iowa DOT Research. (2021). Development of Digital As-Built for Use in Future Asset Management Applications. Iowa Department of Transportation.https://ideas.iowadot.gov/subdomain/stic-incentive-funds/end/node/3410?qmzn=iKFrYf

Kentucky Transportation Center. (2019). Redefining Construction As-Built Plans to Meet Current Kentucky Transportation Cabinet Needs. Kentucky Transportation Cabinet. https://uknowledge.uky.edu/ktc_researchreports/1630/

National Cooperative Highway Research Program. (2015). Advances in Civil Integrated Management. Scan Team Report. NCHRP Project 20-68A, Scan 13- 02. http://onlinepubs.trb.org/onlinepubs/nchrp/docs/NCHRP20-68A_13-02.pdf

Nevada Department of Transportation. (2021). CAD Standards and Information. Nevada Department of Transportation. https://www.dot.nv.gov/doing-business/about-ndot/ndot-divisions/engineering/design/cadd-standards-and-information

North Carolina Department of Transportation. (2020). Perspectives on Anticipated OpenRoads Designer (ORD) Technological Benefits. North Carolina Department of Transportation. https://connect.ncdot.gov/resources/CADD/OpenRoads%20Designer%20Documents/NCDOT%20Research%20and%20Innovation%20Summit_ORD%20Presentation_10-14-20_Final.pdf

Pennsylvania Department of Transportation. (2020). Digital Delivery Directive 2025 Final Strategic Plan. Pennsylvania Department of Transportation. https://www.penndot.gov/ProjectAndPrograms/3D2025/Documents/Final%20Strategic%20Plan%20V1.0.pdf

Utah Department of Transportation. (2021). Digital Delivery. Utah Department of Transportation. https://digitaldelivery.udot.utah.gov/pages/bdc1336e1ade43d5bac2deca0e3e4837

Virginia Department of Transportation. (2020). 3D Model Development Manual. Virginia Department of Transportation. http://www.virginiadot.org/business/resources/LocDes/3D_Model_Development_Manual.pdf

Virginia Department of Transportation. (2019). Instructional and Informational Memorandum. Virginia Department of Transportation. http://www.virginiadot.org/business/resources/LocDes/IIM/IIM118.pdf Washington State Department of Transportation. (2017). Electronic Engineering Data Standards. Washington State Department of Transportation. https://wsdot.wa.gov/publications/manuals/fulltext/M3028/ElectronicEngDataStandards.pdf

Targeted Overlay Payment Solutions (TOPS): NJDOT Example Featured

Posted on August 30, 2021September 1, 2021

This article first appeared in the FHWA’s EDC News Weekly Newsletter of August 26th, 2021 and featured NJDOT’s application of high performance thin overlays (HPTO) as a pavement preservation tool.

Targeted Overlay Pavement Solutions

Last week, we discussed a case study involving bonded concrete overlays, part of the Targeted Overlay Pavement Solutions (TOPS) toolbox. This week, we’ll look at how New Jersey has used high performance thin overlays (HPTO) successfully as a pavement preservation tool.

Since 2015, NJDOT has used HPTO on more than 1,000 lane miles to seal pavement and improve ride quality. Benefits include short road closures reducing impact on traffic, and addition of approximately 10 years of service life. Timing of the application is crucial. A Rutgers University study found applying HPTO to pavements while they are still in “good” condition more than doubles the service life compared to applying the product to pavements in “fair” condition.

Contractors who construct NJDOT projects have not reported constructability issues or complaints about the mix. NJDOT believes including performance requirements for the mixture, understanding treatment selection and application timing, and requiring project engineers to approve specifications are key factors in the success of HPTO as a pavement preservation tool.

Based on this research and evaluation of projects to date, NJDOT considers HPTO a cost-effective solution that provides a safe, smooth, crack and rut resistant surface that extends the life of the pavement and causes minimal impact on the road users and environment during construction.

Research Spotlight: Evaluating the Pedestrian Hybrid Beacon’s Effectiveness: A Case Study in New Jersey

Posted on August 24, 2021August 24, 2021

A Pedestrian Hybrid Beacon (PHB) is a signalized, pedestrian-activated device designed to increase crossing safety. A recent study conducted by the New Jersey Bicycle and Pedestrian Resource Center (BPRC), funded by NJDOT, examined the efficacy and public awareness of PHBs in New Jersey. The authors, researchers from Rowan and Rutgers universities, found a persistent need to better educate motorists and pedestrians in New Jersey on the PHB and its phases.

The five phases Pedestrian Hybrid Beacon’s (PHB) operations

Pedestrian Hybrid Beacons are one of FHWA’s seven Safe Transportation for Every Pedestrian (STEP) countermeasures, proven methods of reducing pedestrian collisions. STEP was promoted through multiple rounds of the FHWA’s Every Day Counts (EDC) Program. A PHB is typically placed to improve pedestrian safety at uncontrolled and mid-block crossings, in locations with high pedestrian demand and wide roadways. The treatment consists of two signal arms on each side, with pedestrian “push buttons” and a crosswalk. The PHB operates in five phases. In the first, the PHB’s signal is off. The second phase begins when a pedestrian activates it by pressing a button, prompting the signal to flash a yellow light. Then, for the third phase, the flashing transitions to a solid yellow light, communicating to drivers that they should prepare to stop. Then the light turns red, and, in the fourth phase, the pedestrian signal changes to “Walk.” After an interval, the fifth phase begins: the pedestrian signal displays a countdown timer, and the traffic signal flashes alternating red lights, telling drivers to stop and that they may proceed if the crosswalk is clear.

The study’s literature review found multiple examples of prior research demonstrating the efficacy of PHBs. In the case of Tucson, Arizona, where one of the first PHBs was deployed in the United States, one study found a 69 percent decrease in pedestrian-related crashes in the signal area. Another analysis in Tucson found a 97 percent yielding rate from drivers at PHB-equipped crossings. One of the chief findings from the literature review was that PHB signal evaluations were lacking in New Jersey. Thus, researchers aimed to more systematically analyze PHBs in the state.

The authors found ten implemented examples of PHBs throughout the state, from Bergen County to Atlantic County. For more in-depth research, they selected signals in three different community types (urban, suburban, and campus area), in Morristown, Medford, and New Brunswick, New Jersey, to undergo video analysis.

The five phases Pedestrian Hybrid Beacon’s (PHB) operations

One commonality observed in all three locations was an apparent confusion for motorists concerning the fifth phase, in which the signal flashes red, indicating that drivers should stop and then proceed with caution. In New Brunswick, 100 percent of observed motorists remained stopped, even after the intersection had been cleared. In Morristown, the vast majority of pedestrians (91.3%) failed to use the PHB during the morning period, and also failed to do so in the evening (83%). The authors attribute such behavior to the PHB timing being linked to two nearby traffic signals, contributing to extra delay after the crossing button has been pressed. When inconvenient, it seems, pedestrians may opt to cross on their own.

To better understand the familiarity of pedestrians and motorists in New Jersey with PHBs, the researchers designed an online survey that was sent to 79,567 randomly selected email addresses from 30 communities across the state. While respondents indicated some confusion as to how PHBs functioned, a plurality indicated that they would be very likely or somewhat likely to support implementation in their own community. A majority of respondents (85.9%) reported that they had never heard of PHBs, and later indicated that completing the short survey had increased their knowledge of the safety treatment, showing the potential benefit of more public education about their functionality.

The report concludes by stating that while PHBs are proven to be effective at increasing pedestrian crossing safety, a lack of public awareness on the part of both drivers and pedestrians currently limits the effectiveness of these devices. The researchers suggest updating the New Jersey Motor Vehicle Commission’s Driver’s Handbook to include the PHB, and to differentiate the flashing red signals at a PHB where the driver must yield and then proceed if the crosswalk is clear, from the flashing red signals at railroad crossings where the driver is required to stop and remain stopped. This addition could be complemented with a public education campaign to teach pedestrians and drivers about the intricacies of Pedestrian Hybrid Beacons.

The New Jersey Bicycle and Pedestrian Resource Center (BPRC) works to promote a safer and more accessible walking and bicycling environment in the state. The Center, located at the Alan M. Voorhees Transportation Center at Rutgers, is supported by NJDOT through funding from FHWA. Further information technical assistance, resources for Complete Streets, and current research is available on the BPRC’s website.

Resources

Federal Highway Administration. Pedestrian Hybrid Beacons. Federal Highway Administration. https://safety.fhwa.dot.gov/provencountermeasures/ped_hybrid_beacon/

New Jersey Bicycle and Pedestrian Resource Center. (2020). Evaluating the Pedestrian Hybrid Beacon’s Effectiveness: A Case Study in New Jersey. New Jersey Bicycle and Pedestrian Resource Center. http://njbikeped.org/portfolio/evaluating-pedestrian-hybrid-beacons-effectiveness/

NJDOT Tech Transfer. (2019). What is a Pedestrian Hybrid Beacon? NJDOT Tech Transfer. Video. https://www.njdottechtransfer.net/2019/09/27/njdot-safety-countermeasures-videos/

NJDOT Tech Transfer. (2020). STEP-Aligned HAWK Signal Installed in Bergen County. NJDOT Tech Transfer. https://www.njdottechtransfer.net/2020/03/20/step-aligned-hawk-signal-installed-in-bergen-county/

Launching the UAS Program: STIC Incentive Funding Grant – Final Report

Posted on August 6, 2021August 9, 2021

Click for report

Unmanned Aerial Systems (UAS), or drones, were promoted by the Federal Highway Administration (FHWA) as one of the Every Day Counts Round 5 (EDC-5) innovations. In 2017, the NJDOT Bureau of Aeronautics applied for and received a NJ State Transportation Innovation Council (STIC) Incentive Program Funding grant to purchase equipment and provide training to evaluate the use of UAS for applications within NJDOT. Prior research had determined that this innovative technology could improve safety and efficiency and reduce costs.

The final report, Unmanned Aircraft System (UAS): Purchase and Training, describes the use of the STIC funding to assist in establishing the UAS program within the Bureau of Aeronautics. The report describes the training curriculum and two use cases — high mast inspection and traffic incident management — and offers lessons learned and best practices.

The STIC grant, in combination with two other grants, enabled the Bureau to advance UAS within NJDOT. The innovation is now considered institutionalized within the agency. A video, Drone Technology at NJDOT, highlights the efforts to launch and integrate UAS in NJDOT operations.

FHWA offers up to $100,000 to each STIC each year. You can find out more about the STIC Incentive Program here.

Ultra-High Performance Concrete for Bridge Preservation and Repair: NJDOT Example Featured

Posted on July 30, 2021August 6, 2021

This article first appeared in the FHWA’s EDC News Weekly Newsletter of April 29th, 2021 and featured how NJDOT has applied UHPC for bridge preservation and repair.

In the final week, we’ll highlight the New Jersey Department of Transportation (NJDOT), which has recently used UHPC in multiple projects for bridge P&R.

NJDOT was familiar with the benefits of UHPC compared to conventional concrete through its use in field cast connections for precast bridge decks for re-decking projects. NJDOT had been looking for a new overlay preservation system for aging bridge decks that would enhance and extend the service life of their existing structures. However, the NJDOT had not used UHPC as a bridge deck overlay. NJDOT decided to install three UHPC bridge deck overlays as part of a research project contract. One of these projects, which was completed on a bridge spanning the Newark Turnpike, included both a UHPC bridge deck overlay and field-cast UHPC joint headers.

This curved 3-span bridge, originally built in 1979, feeds nearly 30,000 vehicles per day from the New Jersey Turnpike onto I–280. The heavy traffic and the impact of de-icing salts resulted in corrosion of the reinforcing steel in the existing bridge deck, as well as the deterioration of all abutment and pier expansion joints.

Prior to installation of the UHPC overlay and field cast UHPC headers, the existing asphalt overlay was removed, as were the deteriorated expansion joints. A new UHPC header expansion joint solution was installed, and after installation the finished UHPC overlay was covered with asphalt. The resulting 340-foot UHPC overlay is currently the longest continuous overlay installation in North America.

The overlay and the other two installations included in the project showed that preserving bridge decks with a UHPC overlay will provide NJDOT with durable, long-lasting bridge decks and will extend the service life of the structures. Additionally, the bridge overlays showed that UHPC overlay construction methods can minimize traffic interruptions and shorten the total construction time.

Post card style image reads: Built a Better Mouse Trap: National Recognition Program for Transportation Innovation

ANNOUNCEMENT: NJLTAP – Innovating at the Local Public Works Level: Can you Build a Better Mousetrap? (Webinar)

Posted on July 27, 2021July 28, 2021

The New Jersey Local Technical Assistance Program (NJLTAP) will host a webinar on the FHWA’s Build a Better Mousetrap program’s collaboration with local technical assistance programs across the country.

The webinar will present examples of new tools and processes that have been developed and celebrated by the program—innovations that reduce cost, increase safety, and contribute to a more efficient transportation system.

The event will be held on Wednesday, August 25, from 10am to 11am. Those interested in attending may register here.

Reads: Lunchtime Tech Talk! The NJDOT's Pavement Support Program (PSP), Goals, Deliverables, and the Future, Thursday July 22, 2021, 12pm to 1:15pm

Lunchtime Tech Talk! WEBINAR: NJDOT’s Pavement Support Program—Goals, Deliverables and the Future

Posted on July 26, 2021August 5, 2021

Dr. Thomas Bennert, of the Center for Advanced Infrastructure (CAIT) at Rutgers University, presented on Thursday, July 22, on his work leading the Pavement Support Program (PSP) for NJDOT’s Pavement & Drainage Management and Technology Unit. Dr. Bennert discussed in detail PSP’s current research and applications, explaining how a variety of innovative materials and technologies are being developed and applied to improve pavement performance across the state.

Dr. Bennert's talk provided an overview of the pavement program’s recent deliverables, as well as highlighted the future goals of the program. The PSP has several objectives and touches upon many disciplines from materials evaluation to supporting pavement management activities to addressing pavement design needs to assisting in training and workforce development. The PSP serves as an extension of the NJDOT workforce activities under the direction of the Pavement & Drainage Management and Technology Unit at NJDOT, which also helps to support the needs of the NJDOT Materials Bureau to inform materials characterization for more accurate pavement design and evaluation.

Since 2006, the PSP has assisted NJDOT through research and technical assistance related to pavement performance. Because of this continual, fifteen-year operation, data is available today that demonstrates the positive effects of the program’s work, such as how various asphalt composites have performed over time in comparison to traditional asphalt mixes.

Slide reading NJDOT Pavement System, how it's going. A bar graph of deficient, fair, and good pavement statuses, with deficient tending down since 2006, and good trending upwards.

Data indicates a steady upward trend in the condition of New Jersey’s highway pavement, due to the sustained implementation of PSP’s research and deployment of various pavement preservation treatments

Dr. Bennert organized his talk by the seven major support tasks of the PSP, highlighting the purpose, examples and upcoming activities for each task. For the program’s first task, Innovative Materials, the program has focused on the development and improvement of specifications for roadway pavements, such as asphalt and concrete, to extend the life of the pavement. High Performance Thin Overlay (HPTO) was one of several examples whose purpose, design attributes and benefits were discussed. This pavement treatment improves rut and crack resistance, and extends the life expectancy of some pavements by over five years.

Dr. Bennert also touched on the rationale and challenges of applying another materials innovation, High Friction Surface Treatment (HFST), which was promoted as an FHWA Every Day Counts (EDC) initiative in 2015. While horizontal curves make up only 5 percent of U.S. roadways, more than 25 percent of total roadway fatalities occur on these sections. One way to increase friction in these areas is to apply an HFST, though the pavement must be in good condition. In New Jersey, rapid temperature swings can affect the epoxy on degraded asphalt, creating shallow potholes. To counter this failure, Dr. Bennert and his team have developed both a pre-screening protocol to determine whether a curve is suited for HFST, and a different adhesive more suited to asphalt.

Slide reads Task 2 - Pavement Bonding (Tack Coats & Bond Strength Test), with immages of defromed pavement. A graphic shows how tension between two layers of pavement that are not properly bonded creates space for friction. Bullet points read: Pavement construction requires construction layers in "lifts." Pavement design is conducted assuming layers are "fully bonded," Poor bonding in HMA layer is associated with, reduced fatigue life, increased drutting, and slippage, cracking, and instability.

The program team developed ways to improve pavement bonding in roadway construction

PSP is also tasked with researching innovative practices and technologies to improve the efficacy of the paving process. One example that Dr. Bennert shared involved researching ways to improve the pavement bonding. Two common problems are slippage, where the top layer does not adhere properly and begins to slide away, and more widespread tension issues, in which failure to bond causes uneven loads, warping the pavement. To avoid premature failure, the program has developed performance-based specifications for tack coats (the term for the adhesive layer between tiers of asphalt), a testing mechanism to better understand the properties of tack coats, and new criteria for construction practices to ensure that pavement is put together properly.

The PSP includes a pavement management system support task to assist NJDOT in the collection of data, the management and quality control of data, and the application of data to inform decision-making priorities. For example, the NJDOT Pavement Management group conducts yearly pavement condition assessments to help forecast needs of pavement activities and funding allocations to optimize budgetary resources for pavement preservation and larger rehabilitation and reconstruction projects. This process uses Pavement Management Systems (PMS) condition and program mapping, and future work is expected to continue to incorporate GIS mapping models to create an even more comprehensive picture.

Until recently, the status of the state’s many miles of pavement has been historically performed using an employee’s vision and judgment. Instead, PSP is looking to deploy cameras and computer-based processing power along roadways to automate data collection for developing surface distress index ratings, and even to calibrate and predict the infrastructure’s future performance to inform Pavement Design.

Slide is a map of New Jersey with colored lines across its roads, reflecting pavement conditions. Text to the left reads Developing Visual Tools that NJDOT PMS can utilize for programming and reporting, Construction programming, Planning, Pavement Preservation, and Rehab and Reconstruction

New methods in data collection and mapping allow for a more comprehensive picture of pavement conditions across the state

Finally, PSP engages in policy analysis, develops white papers on current and emerging practices, and provides technology transfer and trainings for NJDOT. Such work includes Cost Benefit Analyses (CBAs) to determine the cost effectiveness of new materials, tackling the question of whether the additional costs to manufacture can be justified by the additional years added to the roadway’s life cycle. Dr. Bennert shared slides showing how CBAs of HPTO and several other hybrid asphalt mixes had higher Benefit/Cost Ratios than traditional Hot Mix Asphalt (HMA). The program engages in trainings and presentations with NJDOT regularly, presenting on research and technological innovations, and facilitating technology transfer and continuity for newer staff.

Dr. Bennert concluded his presentation by commending NJDOT as a national leader in performance testing for asphalt and handling of composite pavements. The Pavement Support Program will continue to address the immediate needs of the Pavement & Drainage Management and Technology Unit at NJDOT, sustaining their research, development, and implementation of cutting-edge pavement technologies. “What we’re doing here is making a big impact in the state.” Dr. Bennert said.

Afterward, Dr. Bennert answered audience questions in a brief Q&A.

Q. How does New Jersey compare to other states in our use of high performance thin overlay (HPTO)?
Dr. Bennert: We’re working with FHWA on the EDC-6 rollout of HPTO. We use it significantly more than most states, besides Texas. New Jersey is a leader on performance testing in general.

Q. How widespread is the use of the High Friction Surface Treatment (HFST) in New Jersey?
Dr. Bennert: While I don’t have the crash reduction data, I do know that it’s been used successfully by the state and some municipalities as well. As shown earlier, there have been some failures with the technology’s application, which we are now working to identify the reasons for failure and reduce through our research.

Q. As reported in the HFST guidelines, why do you think an early drop in skid resistance was observed in the treatment’s application, despite the very hard aggregate that was used?
Dr. Bennert: Simply, it is due to the material loosening in the epoxy. The embedment depth of that aggregate is very important. If it’s too deep, the aggregate is almost drowning in the epoxy, and if it too shallow, it can pull out very easily as vehicles travel over it. The recommendation is to monitor the HFST over the first few years. Because HFST has a limited shelf-life, monitoring friction is very important.

Q. How many sub-consultants do you have on this project, and which private consultants are contracted as sub-consultants?
Dr. Bennert: Currently, the only group that we have working with us on the contract this year is the company that manufactures the software for the pavement management system. This can change based on the needs of Pavement & Drainage Management and Technology Unit at NJDOT.

Q. Could you speak on pavement mix testing for future climate concerns?
Dr. Bennert: We have tests and thresholds for how the material should be performing, and additional heat will often stiffen the material a bit more, which can further age the pavement. We could get some increased, accelerated stiffening. PSP has been working with NJDOT on test methods to identify appropriate asphalt materials and test methods to help identify materials that are prone to aging, which could be especially useful to address climate concerns.

Q. What is the future of Cold Mix Asphalt and its potential use on heavily truck trafficked New Jersey highways?
Dr. Bennert: In New Jersey, we don’t have low volume roads where we could put material out without an overlay. Without some kind of confinement, the material could easily break apart. I’m looking forward to the rollout of central plant technology, which will allow us to take material from a project and put that back, an almost 100 percent recycling of the material for a project’s base application. This would be a base application to help reduce the recycled asphalt pavement stockpiles in the state.

Q. Did you test Ultra-Thin Friction Course and how does it compare to High Performance Thin Overlay?
Dr. Bennert: Ultra-Thin Friction Course can be thought of as a treatment option between an Open-Graded Friction Course and a Chip Seal. It’s used more for pavement preservation, rather than structure, but it does a good job at sealing off the pavement. The High Performance Thin Overlay is thicker, and helps to provide structural integrity of the pavement, both sealing it and adding rutting and cracking resistance. There’s a difference in the thickness of the materials, and the targeted applications.

A recording of the webinar is available here, (or to the right).

Dr. Bennert’s presentation can be found here.

Resources

Federal Highway Administration. Targeted Overlay Pavement Solutions. https://www.fhwa.dot.gov/innovation/everydaycounts/edc_6/targeted_overlay_pavement.cfm

Bennert T. and D. Pezeshki. (2015). Performance Testing for HMA Quality Assurance. Report, Rutgers, Center for Advanced Infrastructure and Technology. FHWA-NJ-2015-010. https://cait.rutgers.edu/wp-content/uploads/2018/05/fhwa-nj-2015-010.pdf

NJDOT Technology Transfer. Pavement Preservation at NJDOT. Video. https://www.youtube.com/watch?v=n1wlnB8AQ-g&t=128s

ANNOUNCEMENT: FY 2021 AID Demonstration Program Information Session

Posted on July 21, 2021July 27, 2021

The Federal Highway Administration (FHWA) has announced the FY 2021 Accelerated Innovation Deployment (AID) Demonstration Program and will make up to $10 million in grants will through Notice of Funding Opportunity (NOFO) 693JJ321NF-AIDDP (link). The AID Demonstration program provides funding as an incentive to accelerate the implementation and adoption of innovation in highway transportation. Eligible activities may involve any phase of a highway transportation project between project planning and project delivery, including planning, financing, operation, structures, materials, pavements, environment, and construction. The FHWA will provide AID Demonstration grants to eligible State DOTs, Federal Land Management Agencies, and tribal governments.

Key NOFO Dates

Notice of Intent to Apply Deadline: August 3, 2021: 11:59 pm Eastern Time.
Application Submission Deadline: September 28, 2021; 11:59 pm Eastern Time.

The FHWA will host an AID Demonstration Information Session to provide an overview of the FY 2021 program. Participation is not mandatory in order to submit an application under NOFO 693JJ321NF-AIDDP. However, potential applicants are encouraged to participate. Please join us on July 27, 2021 at 1:00 pm (Eastern Time). There is no registration required to attend the Information Session. To join, simply CLICK HERE to be taken directly to the virtual meeting space. This will be a MS Teams Live Event and will be recorded.

Image of a highway with two cars driving on it, in the distance the erector-set outline of the Pulaski Skyway can be seen.

To Replace Falling Gas Tax Revenues, Eastern States Explore Mileage-Based User Fees

Posted on July 8, 2021July 26, 2021

Traditional fuel usage is expected to plummet as the country transitions to zero-emission vehicles (ZEVs). State and Federal gas taxes, traditionally the predominant source of transportation infrastructure funding, will no longer suffice with this vehicular fleet transition. In New Jersey, for example, the state’s plans for carbon-neutrality by 2050, will eliminate the roughly $2 billion generated from gas taxes each year—funds that are needed to keep our roadways in a state of good repair. One solution, proposed by the Eastern Transportation Coalition, is a mileage-based user fee (MBUF), which generates revenue by miles traveled, instead of gallons of fuel purchased. An MBUF could ensure that electric vehicle (EV) users pay their fair share for the upkeep of New Jersey’s roads.

To solve this looming funding gap, a consortium of states along the Atlantic seaboard, collectively known as the Eastern Transportation Coalition, are working to engage with the public on, and study the possibility of, implementing a Mileage Based User Fee (MBUF). The organization is currently piloting multiple programs for both freight and passenger vehicles, including a study involving New Jersey drivers that concluded in late 2020.

Document cover, in white and blue, reading The Eastern Transortation Coalition (Formerly the I-95 Corridor Coalition) Mileage-Based User Fee Exploration 2019 Passenger Vehicle Pilot, Final Report, March 01, 2021

The Mileage-Based User Fee Exploration is one of several studies by the Eastern Transportation Coalition examining how to make up a loss of gas tax revenue. Courtesy The Eastern Transportation Coalition

In March, 2021, the Coalition published a detailed report containing findings from a 2019 Passenger Vehicle Pilot in Delaware and Pennsylvania. The study was funded by a grant from the United States Department of Transportation’s Surface Transportation System Funding Alternatives (SFSTA) program. While the pilot was based in Delaware and Pennsylvania, the 889 participants represented fourteen member states, including New Jersey, and the District of Columbia.

The organization gave participants an option for how their miles would be tracked. Using a device provided by a vendor, Azuga, they had the choice of a sensor with geo-positioning functions, or one without, which would use a predefined estimate to determine mileage allocation. Location services for such a tracker are essential for the East Coast region, where interstate travel is more frequent. Out of the 3.13 million miles pilot program participants drove, 13 percent of miles were outside of their home state.

Both devices included “value-added” features, which collect data on vehicle health, driver performance, trip logs, and battery performance. At the end of the study, a majority of respondents indicated that they appreciated these features.

To estimate charges, the Coalition created a miles-traveled tax rate for each state, multiplying the state and federal gas tax average by monthly mileage, with an additional 20 percent rate multiplier to cover projected administrative costs. For example, a New Jersey driver with an average fuel economy vehicle driving 1,000 miles per month would pay $87.64 under the MBUF—or about a cent more than they currently pay in state and federal gas taxes. However, under the program, a driver with a hybrid car, such as a Toyota Prius, would be required to pay an additional $10.43. For an EV driver, who currently avoids paying the gas tax entirely, the MBUF program would obligate them to pay $18.69 a month toward road maintenance for the same distance. (See figure below). The organization provides a mileage calculator for members of the public to explore how much they would pay under the proposed system.

From Left to Right: Milage calculator tool for MBUF for average vehicle with 23 Miles per gallon, they would pay about one cent more in fees to drive 1000 miles. Second: Hybrid mileage calculation for 1000 miles with 2018 toyota prius, they would pay $10.43 more under MBUF than the $38.76 they currently pay, and third and finally: Mileage calculation for EV driving 1000 miles, they would have to pay an extra $18.69, and are paying $0 now using traditional gas tax.

From left to right, an average vehicle, hybrid vehicle, and electric vehicle and their respective MBUF costs. Courtesy The Eastern Transportation Coalition

During the pilot program, the Coalition conducted surveys before and after, and held focus groups with participants, to gauge changes in perception. One survey found that 70 percent of New Jersey respondents thought that transportation funding is growing or the same, despite falling gas tax revenues. By the end of the test period, 85 percent of participants said that the MBUF device was helpful and easy to use, and concerns about privacy dropped by nearly half.

From 2018-2019, the organization conducted a study with freight vehicles, forming a Motor Carrier Working Group (MCWG) with industry partners. The pilot included 55 tractor-trailers that traveled a total of 1.43 million miles over the six-month period. The overall conclusion was that trucks themselves are varied, and, as a class, entirely dissimilar to cars. Trucks typically include trackers as part of the International Fuel Tax Agreement (IFTA), a tax redistribution system, and the International Registration Plan (IRP), which calculates registration fees according to fleet distance through various jurisdictions. However, such a system would be incompatible with MBUF because it lacks revenue collection tools, location services, and consistent implementation. This study found that the MBUF must be adjusted to the type of vehicle and service it provides, or else it unintentionally privileges certain carriers. To further gauge the intricacies of MBUF for commercial trucking, the Coalition began another freight truck pilot in the fall of 2020 with 200 vehicles.

The Eastern Transportation Coalition summarizes six key takeaways from their last four years of studies as follows:

More outreach is necessary to increase public awareness of the funding gap.
The transition to any new funding mechanism will be difficult.
Privacy concerns were dispelled after testing the new technology.
MBUF would relieve the disproportionate share of maintenance costs borne by rural drivers with inefficient vehicles.
Freight trucks require a program tailored to them, and cannot be considered the same as cars.
People were generally in favor of the MBUF model, but more education about its importance and functionality is needed.

image of a blue eighteen wheeler with a long white trailer driving on a highway with trees losing their leaves on an overcast day.

The Coalition's studies have demonstrated that MBUF for freight must be tailored to type and service. Joseph Paul | Unsplash

Dr. Patricia Hendren, Executive Director of the Eastern Transportation Coalition, shared these findings with the Senate Committee on Environment and Public Works in April, 2021. Dr. Hendren stressed that a federally-led, national education campaign about dwindling transportation funding was necessary, to boost public awareness about this growing concern. In addition, the executive director advocated for further studies at state and regional levels of both passenger and commercial vehicles, to ensure that that such a transition will be equitable, efficient, and have strong public support.

It is certain that a switch from the traditional gas tax funding system is necessary to maintain America’s road infrastructure, and mileage-based user fees are a promising mechanism for doing so—one way to ensure that everyone pays their fair share.

Resources

The Eastern Transportation Coalition. (June, 2020). Findings from the Nation’s First Multi-State Truck Mileage-Based User Fee Pilot The Eastern Transportation Coalition. https://tetcoalitionmbuf.org/wp-content/uploads/2020/08/2018_2019-Coalition-Truck-Pilot-Factsheet_FINAL.pdf

The Eastern Transportation Coalition (March, 2021). Mileage Based User Fee Exploration: 2019 Passenger Vehicle Pilot. The Eastern Transportation Coalition. https://tetcoalitionmbuf.org/wp-content/uploads/2021/03/TETC-2019-Passenger-Vehicle-Pilot-Report-1.pdf

The Eastern Transportation Coalition. (March, 2021). Six Things to Know About Mileage-Based User Fees. The Eastern Transportation Coalition. https://tetcoalitionmbuf.org/wp-content/uploads/2021/03/TETC-March-2021-Fact-Sheet.pdf

The Eastern Transportation Coalition. (April, 2021). Testimony of Patricia Hendren, Ph.D., Executive Director, the Eastern Transportation Coalition. The Eastern Transportation Coalition. https://www.epw.senate.gov/public/_cache/files/3/b/3b09198c-a0b3-4d41-b7ad-f21ae38c9579/C45ABD53D65A339B09EDF69FC3A367A0.04-14-2021-hendren-testimony.pdf

The Eastern Transportation Coalition. What Could it Cost? The Eastern Transportation Coalition. https://tetcoalitionmbuf.org/mbuf-cost/

Image reading WEBINAR Lunch Time Tech Automating the Traffic Signal Performance Measures for NJDOT Adaptive Traffic Signal Control Systems

Lunchtime Tech Talk! WEBINAR: Automating Traffic Signal Performance Measures for NJDOT Adaptive Traffic Signal Control Systems

Posted on July 1, 2021August 5, 2021

Slide Cover Reading Lunchtime Tech Talk! Automating the Traffic Signal Performance Measures for NJDOT Adaptive Traffic Signal Control Systems - Real-Time Signal Performance Measurement (RT-SPM)

Click For Tech Talk Presentation

The New Jersey Department of Transportation Bureau of Research convened a Lunchtime Tech Talk! Webinar on Automating the Traffic Signal Performance Measures for NJDOT Adaptive Traffic Signal Control Systems on June 29, 2021. The presentation was led by Dr. Peter Jin, of Rutgers-CAIT, Dr. Thomas Brennan, from the College of New Jersey, and Kelly McVeigh from NJDOT’s Mobility Engineering Unit. The three touched upon Phase I research on Real-Time Traffic Signal Performance Measurement and continuing research underway in Phase II to adapt NJDOT’s existing signaling technology to take advantage of innovative methods in optimizing traffic controls.

Kelly McVeigh, of NJDOT, began the event by introducing the Automated Traffic Signal Performance Measures (ATSPM) and Adaptive Traffic Signal Control Systems (ATSC) concepts. According to McVeigh, Automated Traffic Signal Performance Measures are a suite of measures that help transit agencies to make use of data in optimizing signal timings. ATSPM consists of a dataset of time-stamped events—visually represented through charts—that demonstrate the signal’s performance. For example, how much time the signal is set to green when vehicles are present. The technology, McVeigh said, was “a powerful tool in the toolbox for traffic engineers to monitor performance and even make changes, if agency procedures allow.” ATSPM was first introduced by FHWA as part of the fourth round of the Every Day Counts Initiative (EDC-4).

Slide Reads Challenges with Standard ATSPM Deployment, Standard ATSPm Deployment: High-resolution controllers, data probe and FTP configuration at Signal Boxes. Challenges: Upgrading to high-resolution controllers requires significant investment, $4,000 to $5,000 dollars per intersection. Opportunities: Centralized event logs of Adaptive Signal Control Technology systems. Rapid expansion of ASCT systems. Objectives: Integrate ATSPMs and Adaptive Signal Control Technology )ASCT) systems to produce ATSPM performance metrics. Policies: Dynamically adjust the signal timing in real time in practice. Timing changes (long-term) versus ASCT (real-time/short-term).

In order to avoid costly infrastructure costs of replacing ASCT systems for ATSPM equipment, the researchers devised a method to make use of existing, deployed intersection systems.

McVeigh explained that, while there is already a well-documented system in place to support ASTPM implementation, NJDOT is focusing on adapting existing systems that are already equipped to capture data. Adaptive Traffic Control Systems (ATSC) are installed in nearly 20 percent of NJDOT’s roughly 2,500 signals statewide, and collect data on both traffic controllers and detectors, such as signal performance and vehicle queuing. However, as Dr. Jin then detailed, ATSC data is presently incompatible with ATSPM. In addition, some signals are connected to the centralized network, while others remain isolated. The solution was to develop a means of converting the data, rather than installing new infrastructure.

A team of students from Rutgers, The College of New Jersey, and Rowan University worked with Dr. Jin to bridge data from ATSC to ASTPM. The proposed solution is a program that automatically retrieves traffic controller event logs and then translates them into ASTPM event code, a method that is agnostic to controller type. This allows for a wide variety of data to be collected, and then viewed and optimized using standard ASTPM methods.

Slide image of proposed farmework with a new add on of existign ASCT Sytems going ot get event logs, to ASCT event translator to push ATSPM events, to Database server. The two bullet points read The Newly developed program can automatically retrieve the controller's logfiles and translate records ito standard ATSPM event code. This method is agnostic to the controller type.

The proposed framework would add direct conversion of ASCT events to ATSPM.

Data translation works by taking ATSC logs, such as “Phase Begin Green” stamped with a timecode, and converting that to a numeric code, in this case, “1.” A computer program reads through the SCATS log and assigns certain datapoints to traffic events, such as a gap, which would be coded as “4.” At the conclusion of Phase 1, the team has been able to convert all major events to ASTPM metrics. Going forward, they are working on using geolocated video data to reconstruct stopping data, allowing for more refined information that enables real-time traffic signal adjustments.

Many locations on NJDOT’s network are not properly equipped to convey upstream information on vehicles, particularly during the red phase. The ingenious solution is to locate a “Stop-Bar” within the signal detector that registers when vehicles have begun queuing. This data is then correlated with spatial Google Maps data that precisely locates the vehicles’ position. Information from the Autoscope video-based tracking technology is then used to calculate the vehicle’s trajectory, using the Shockwave Theory of traffic flow. The benefit of such a method is better data on how vehicles approach a red signal, which can then be optimized through ASTPM.

Reads event Translator method, converted signal events will be imported into this ATSPM database. Following this, the ATSPM software can generate performance metrics and produce visualization to suppport maintenance and operations. Table shows signal timing and phase-related event and code used by ATSPMs.

ASTC events are translated using a computer program that can recognize various events and code them as such.

Dr. Brennan then demonstrated the technology in action, sharing his screen to show the ATSPM Server and its variety of tools. He selected a sample intersection, US-1 and Harrison Street near the Millstone River, and brought up a chart showing the Purdue Phase Diagram (PCD). The PCD is a means of graphically representing the number of vehicles passing through an intersection with respect to phase time. In an ideal situation, vehicles should arrive on green, instead of red, when they will have to wait. Another chart represented the traffic split by time of day and duration of the phase. When the technology is fully implemented, such data should be uploaded every 15 minutes, allowing for near real-time monitoring.

From the ATSPM data, Dr. Brennan showed that one signal had an 82 percent Arrive on Green (AoG) score. Metrics such as this could be used for the development of data-driven policy. The dashboard charts also showed vehicle density for when the signal was about to turn red—the timing of which could be adjusted to lighten the number of vehicles queuing.

Screenshot image of a white website with a blue graph, showing dark blue and red squiggles, which are traffic flow data at the intersection throughout the dat. Above, Dr. Tom Brennan can be seen explaining.

A live demo of the converted ATSPM dashboard demonstrated how useful the technology will be for making intersections more efficient.

It was clear that the conversion of ATSC data to ATSPM dramatically expanded the potential of every intersection in which it is equipped. The dashboard could be used to model changes in traffic flow, such as if a road diet were implemented, or if traffic from a major highway was diverted through the intersection. Safety benefits include data on red light violations that can be tabulated and used as justification for future improvements. One day data from connected vehicles could be integrated, too.

At the end of the presentation, Dr. Jin summarized their work: the team had innovated in converting raw data to ASTPM protocols that could then be used to boost signal performance and traffic flow optimization. This translation method avoids the intensive infrastructure cost of upgrading signals to ASTPM standards, saving money. An in-development model using Stop-Bar data will soon allow for real-time signal adjustment, letting traffic engineers tweak signal timings for optimal flow. At NJDOT, they are in the final stage of deploying this technology permanently on an agency server for future widespread use.

At the end of the event, several attendees asked questions through the platform’s chat feature.

Q. Inrix data does not provide individual probe data, how is it accounted for in the results?
Dr. Brennan: We’re not able to get individual vehicles, but it aggregates vehicle speed within one-minute increments. This then feeds that into ASTPM as if it were a single detector. Everything is within a confidence interval of 85 percent. The beauty of this software is that as long as you convert your information into the right format, you can put it in there.

Q. How do you control and change the cycle length tool?
Mr. McVeigh: Part of the adaptive system algorithm is to update cycle lengths in real time, based on the data being received. We can also provide guidance to the system on thresholds, on minimum and maximum lengths for cycles throughout the day. This is all for adaptive systems—coordinated systems use modeling to update their lengths. The tool used primarily at NJDOT is Synchro.

Q. How did the COVID-19 pandemic affect the data collection on Route 1?
Dr. Brennan: Because the researchers were working to calibrate a tool, the volume of traffic on the roadway did not affect their work.

Q. What are the biggest obstacles that you are facing in advancing this innovation around the state?
Mr. McVeigh: The first obstacle is ensuring that various datasets can be interfaced properly, because the ATSC system is providing data that is not necessarily compatible with ASTPM functions.
Dr. Brennan: There are also issues with code syntax, such as when SCATS is updated and logs data differently. Thanks to the graphical nature of the project, it is easy to see when this is happening.

Q. Did you face any issues in reconciling the Google Maps data with the CCTV data?
Dr. Jin: I think it was more with the video conversion. Google Maps provided good distance information that was then converted to become compatible with the video data. The critical step was coordinating these pixel coordinates to actual coordinates.

Q. What percentage of the adaptive signals are implemented on state highways?
Mr. McVeigh: Right now we have 118 adaptive signals in operation. Out of almost 2,600 signals in the state, a little under 20 percent of signals in the state are equipped with this technology.

Q. With multiple data sets fed into the system, how does it filter to avoid repetitions or duplicates?
Dr. Jin: We do have to filter the data that is fed in, and also have developed the logic that shows which line confirms the event occurred, and which line shows the starting point of the event. This is part of the translator work. In terms of different data sources, we were able to coordinate pretty well.

Q. Do you have any suggestions based on your research to help county and local governments advance the implementation of ASTPMs?
Mr. McVeigh: It’s a very powerful tool, make sure you have the practice to enable it to be used properly. From a technical standpoint it’s relatively straightforward, but the big thing is knowing how you want to use it—could be really effectively used as an empirical optimization tool. It all depends on the agency’s ability to do that.
Dr Jin: It is important to start knowing what is currently available, whether there is new construction or existing controllers, to see whether can deploy original ASTPM or these adaptive measures.
Dr. Brennan: It’s important to have strong IT support for these conversion activities. It’s not impossible, but necessary to have the support in place.

A recording of the webinar is available here, (or see right).

Resources

Federal Highway Administration. Automated Traffic Signal Performance Measures. https://ops.fhwa.dot.gov/arterial_mgmt/performance_measures.html

NJDOT Tech Transfer. (2018, December). What is an Automated Traffic Signal Performance Measure (ATSPM)? https://www.njdottechtransfer.net/automated-traffic-signal-performance-measures/

NJDOT Tech Transfer. (2020, June 12). Development of Real-Time Traffic Signal Performance Measurement System. https://www.njdottechtransfer.net/2020/06/12/development-of-rttspms/