APPENDIX E: WHITE PAPER ON ATM ON ARTERIALS

INTRODUCTION

ATM grows more important as mobility problems become more complex and unpredictable. These challenges cross agency boundaries, particularly in urban areas, necessitating partnerships and engagement with local agencies. An example includes congestion from a freeway that spreads to local arterials when drivers are prompted to detour by a third-party mobile application or when an incident closes the freeway. Planned special events require special operating plans and may leverage existing technology for new types of operating strategies. All these situations often go beyond the purview of state DOTs and also require active operations from local agencies. Local agencies are unique in that they have an acute understanding of their jurisdiction; however, their resources (e.g., staff, infrastructure) may be more limited. Unlike freeway facilities, local agencies need to consider users of multiple modes such as pedestrians, cyclists, transit riders, and drivers when developing and implementing ATM strategies. These factors make the topic of ATM on arterials an interesting area to pursue further.

STATE-OF-THE-PRACTICE

A broad range of ATM projects are currently planned and implemented on arterials throughout the United States. This practice is growing as agencies face limited room to increase capacity and more complex traffic problems. The need for more proactive and responsive traffic management is growing, and many arterial transportation agencies are challenged in their ability to operate systems in real time; limited staffing and limited infrastructure are two key challenges that can limit an agencies’ ability to implement robust operating strategies. Some examples of ATM strategies on arterials include but are not limited to the following:

• Dynamic lane assignment. Dynamic lane assignment is a method for managing lanes that uses dynamic messaging to prompt changes in lane assignment. Typically, dynamic lane assignment is used to meet peak hour or event demands.
• ICM. ICM is a cohesive network of corridors and parallel routes intended to maximize person throughput. The behaviors of ICM change based on normal operations, peak hour congestion, major incidents, and evacuations.
• Reversible lanes. Reversible lanes are used to maximize roadway capacity by sending travelers in one direction. They are often used during special events and evacuations.
• Adaptive traffic signal control. Adaptive traffic signal control is a software-based solution that automatically changes the signal operations to meet the changing demands of traffic. This solution can help implement more efficient traffic flow and ease congestion, particularly during peak travel periods or when demand is unpredictable.
• Transit signal priority. Transit signal priority modifies the traffic signal timing or phasing to accommodate transit vehicles as they approach an intersection to facilitate better transit schedule adherence.
• Bicycle and pedestrian detection systems. Bicycle and pedestrian detection systems notify the signal when a bicycle or pedestrian approaches the intersection, typically prompting an extended green or crossing time to promote safety.

CASE STUDIES

The following section provides an overview of ATM arterial case studies. These projects are in different stages of their lifecycle and are located across the country. These projects are unique in their type and application to the local context.

Smart Spines in Pittsburgh, Pennsylvania

The City of Pittsburgh was awarded an Advanced Transportation and Congestion Management Technologies Deployment grant in 2016 to complete the Smart Spines project. This corridor-based approach integrated various travel modes and implemented different ATM strategies. The intersections along the eight corridors (with potential future expansion to nine), use adaptive signal control technology and transit signal priority to accommodate bus rapid transit. The central priority system sits at the center of the project. The cloud-based priority system accommodates priority vehicles, including specific fleet vehicles such as transit and trucks. The passive detection system, which accommodates cyclists, pedestrians, and micromobility users, can categorize vehicle types.

The system has a modal emphasis component, which allows different modes to be set for primary or secondary optimization. Optimization can be done in real time to adjust to changing traffic demands with limited interaction from agency staff, although staff can remotely adjust signal timing plans and corridor modal priority based on real-time conditions. Data is also a focus because it can continually improve the system and gather performance metrics. These performance metrics can be extracted into corridor and annual reports.

The Smart Spines project involves various partners, including the following:

• City of Pittsburgh Department of Mobility and Infrastructure.
• Pennsylvania DOT District 11-0.
• Pennsylvania DOT Bureau of Maintenance and Operations.
• Port Authority of Allegheny County.
• Southwestern Pennsylvania Commission.
• Whitman, Requardt and Associates, LLP.
• Drive Engineering.

Soledad Canyon Road and Sierra Highway Dynamic Lane in Santa Clarita, California

Santa Clarita is the third largest city in Los Angeles County. The city is uniquely positioned between SR-14 and I-5, and drivers often use local streets as a cut-through from one facility to another when an incident occurs. In addition to cut-through traffic, the city experiences congestion as it continues to feel the impacts of its growing residential population. For these reasons, the city has made a concerted effort to optimize the transportation network, and many of these investments are rooted in technology.

Near the intersection of Soledad Canyon Road and Sierra Highway, peak hour congestion occurs during the evening commute. In the spring of 2017, city administrators implemented a series of DMSs bordering the outside lane of Soledad Canyon Road to facilitate efficient movement of vehicles during the peak hour. The message signs permit both through and right turn movements in the outside lane during the peak hour. During all other times, the signs show right turn only.

Following implementation, the city administrators conducted a changeable lane volume analysis in 2019 to identify the system’s performance. They found that the implementation improved operations by 7 percent. Although this outcome reflects an improvement, the relatively small percentage is primarily attributed to the conflicting pedestrian movements at the crosswalk. The pedestrian movements cause delays for vehicles trying to turn right. Despite external challenges, dynamic treatments can be successful in addressing peak hour demand on arterials.

Super Bowl L111 Traffic Operations in Atlanta, Georgia

In 2019, Atlanta hosted the 53^rd Super Bowl at the Mercedes-Benz Stadium. Prepping for a major event like the Super Bowl takes advance notice and engagement from several key stakeholders. The operations team on this project involved several local, state, federal, and private entities including the following:

• Georgia DOT.
• Atlanta Host Committee.
• City of Atlanta.
  • Police.
  • Information Technology/Communications.
  • Traffic.
• FHWA.
• United States Secret Service.
• Atlanta International Airport.
• Georgia State Police.
• SP+ (the National Football League’s transportation provider).
• Project consultants.

The project started by developing a comprehensive playbook that illustrated the various routes, signal timing plans, and messages that would be deployed leading up to, during, and after the event. Several technology components were utilized to enact the playbook, including redundant fiber optic communications, back up 4G cellular towers, fixed and PCMS, and traveler information using the statewide 511 system.

The playbook included specific routes for VIPs such as players, coaches, families, performers, and special guests. Those VIPs that opted to use this service provided by the event, were guided through intersections that were preempted green to promote efficient travel. Additionally, the project team developed routes that minimized overlap, so the escorted groups would not impact one another. DMSs alerted drivers of changing route patterns to help them navigate to preferred routes leading to stadium area parking. Worst-case scenarios were planned to consider the highest level of security threats. More than 10 major corridors near the stadium were changed from one-way to two-way streets. Engineers implemented contraflow patterns and metered traffic near the stadium starting 2 hours before the Super Bowl. Engineers also coordinated with Waze^© to implement time-based turn restrictions into the Waze^© mobile application; effectively routing traffic to a preferred path near the venue.

During game day, two TMCs were in operation: the Georgia DOT’s TMC and the Joint Operations Center that is located inside the stadium. An open phone line was established between the two centers to foster open communication throughout the event. Strategies were tested and refined in advance as part of other events at the stadium.

CONSIDERATIONS AND IMPACTS ON ATM

Several factors should be considered before implementing an ATM project. This section describes some of the necessary considerations.

Institutional Buy-In

Are partners willing to participate and collaborate? In most cases, a siloed approach will not work effectively; therefore, consensus building and stakeholder engagement are very important in creating a successful ATM project. Arterial-based multimodal strategies will often need to engage multiple departments within an agency responsible for planning, bicycles/pedestrians, safety, maintenance, enforcement/public safety, transit, and of course traffic engineering and operations. Some of these stakeholders may only have specific roles at various stages of the ATM lifecycle, but their active participation and involvement is critical to a successful strategy.

Technology and Resource Readiness

Many arterial-focused ATM strategies rely on technology that may or may not be familiar to agency staff that need to plan, operate, and maintain them. Agencies need to be prepared to develop staff capabilities to calibrate, optimize, and operate new technologies; develop new operating procedures; and plan for how those systems will be maintained. Having a full understanding of how the technology needs to perform will help refine ATM strategies and support successful operations. Staff will also need to be prepared to monitor, analyze, and interpret performance to identify where ATM strategies might need to be updated or enhanced. In some cases, vendors or contractors can support some of these functions, but these approaches will also require a funding commitment to get contracts in place.

Balancing Modes

A general industry trend is to emphasize planning for all modes. Historically, transportation planners and engineers have been critiqued for their designs prioritizing the private automobile. With rising greenhouse gas emissions, limited capacity, and a push for more equitable planning, multimodal projects are becoming a priority. The act of balancing modes considers how they impact one another. Earlier, a case study was presented in which pedestrians were found to be causing automobile delay. Tradeoffs will often be required, but promoting a balance of modes and enhancing safety for everyone should be emphasized in ATM arterial projects. Arterial agencies need to factor in multiple modes, including pedestrians and bicycles, as part of any ATM or operations strategy; this issue is not typically relevant for freeway ATM applications.

Understand Local Context

Not all ATM arterial treatments may be appropriate for a particular jurisdiction. It is important to understand the core problem, interrelatedness of systems, potential conflicts, and public perceptions and comprehension. In some cases, the core problem may not necessitate a technology solution but may instead relate more to organization and management. Many times, systems are interrelated, resulting in a problem that is more complex than it appears. Public perceptions and comprehension are vital to a project’s success. A project is not useful if the public

does not want to use it. Lastly, the public’s ability to comprehend the new operations is equally important from both an operational and safety standpoint.

RELEVANCE TO KEY CONCEPTS

Table E-1 summarizes the relevance of ATM on arterials to the major topic categories of the ATM guide. This matrix helped guide the inclusion of ATM on arterials in the final guide.

Table E-1. Relevance of ATM on Arterials to the ATM Guide Topic Categories.

CHALLENGES AND ENABLERS

This section summarizes some major challenges for ATM on arterials.

Establishing Justification for ATM in the Local Realm

Some local jurisdictions may have standard practices for traditional operations, time-of-day signal timing, traffic controller upgrades, loop detection, and general maintenance. For this reason, it is important to turn to precedent ATM successes and establish a business case for ATM to receive buy-in and funding for new projects and new operating strategies.

Training and Availability of Resources

Many local transportation agencies have limited staff; the same person responsible for maintaining signals may also be tasked with reviewing new design plans and responding to inquiries or traffic complaints from the public. In these situations, it is challenging to introduce new technologies and operating procedures. For this reason, it is important to select technologies that can help automate processes to reduce the burden placed on staff. For example, the installation of fiber optic cable can help remote capabilities, which in turn reduces the need for a staff member to physically visit an intersection when a problem arises. Additionally, training is critical to the success of these new implementations. Training can be implemented in-house or outside experts (i.e., vendors or contractors) can be engaged.

Technology Reliability

Risks always exist when pioneering new technology, particularly for local agencies that might be starting with a smaller geographic area to pilot ATM strategies. The agency first needs to learn how to use the system but may also face additional challenges with a new system compared to an established technology. Picking a reputable vendor for equipment is very important. Because of the risk associated with a new technology, it might be valuable to pilot the project along a small segment that can serve as a test bed for future deployments.

Standards, Policies, and Procedures

In theory, innovative projects are encouraged, but agencies often face challenges when implementing projects or technologies that do not yet have a standard, policy, or operating procedure within their agency. For example, if a DMSs deployment does not follow standards defined in the Manual on Uniform Traffic Control Devices for Streets and Highways, it will

likely be received with hesitation. Nonetheless, these standards exist because they have been vetted and approved. Without the safety net of standards, agencies fear potential liability. In an ideal situation, a project is able to demonstrate an innovative application of an existing standard so that it does not face challenges to implementation.

OUTSTANDING ISSUES AND MAJOR GAPS

ATM applications on arterials are broad and unique to the local context. While several examples are discussed in this white paper, these participating agencies are unique among traffic engineers and planners. Far more agencies across the country approach operations through a traditional traffic engineering lens. Traditional traffic engineering is what is taught and what is known. Opportunities exist to expand knowledge of ATM and its applicability and versatility in the traffic engineering industry. This effort can be viewed as twofold—begin by branding ATM as applicable and approachable for all jurisdictions and then incorporate ATM into general traffic engineering education such that ATM strategies are as familiar as traditional traffic engineering strategies.

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