Recurring Traffic Bottlenecks: A Primer
Focus on Low-Cost Operational Improvements
What is FHWA Doing to Promote Congestion Relief and Bottleneck Mitigation?
With regard to congestion, the Federal Highway Administration (FHWA) promotes a number of efforts to help reduce congestion on the nation’s highways. Together with our state partners, who implement these strategies, these efforts can allow for more informed decisions, better coordination, and quicker actions to mitigate the problems.
Recurring Congestion Program Strategies
Tolling and Pricing. Value pricing entails fees or tolls for road use which vary by level of vehicle demand on the facility. Fees are typically assessed electronically to eliminate delays associated with manual toll collection facilities.
Public-Private Partnerships. Public-private partnerships (PPP) refer to contractual agreements between a public agency and private sector entity that allow for greater private sector participation in the delivery of transportation projects. FHWA is working with our partners in the public and private sector to further investigate these promising partnerships.
Real-Time Traveler Information. This is “decision-quality” information that travelers can access, understand, and act on to choose the most efficient mode and route to their final destination. Timely and detailed information about traffic incidents, the weather, construction activities, transit and special events, all aid in improving travel time predictability, better choices, and reduced congestion.
Corridor Traffic Management. When congested traffic conditions occur on one roadway, travelers typically respond by shifting to another route, selecting a different roadway (freeway versus surface street), adjusting their trip to another time of day, or remaining on their current route encountering significant delays. The proactive use of managed lane strategies, alternate routing of traffic, and proactively managing and controlling traffic within freeway corridors offer are a few useful approaches.
Arterial Management and Traffic Signal Timing. Signal timing should correspond to the current traffic patterns. Often signals are initially timed, but not readjusted when traffic patterns change. This results in inefficiency and unnecessary delays. Goal: work with state and local agencies in congested metropolitan areas and encourage best practices for improved traffic signal timing.
Active Traffic Management. In layman’s terms, “actively managing the traffic” means to make real-time adjustments to the facility to manage the speed, density, or safety conditions thereon. Active Traffic Management (ATM) or Active Transportation Demand Management (ATDM) are brother and sister terms, wherein, the former is typically applied only to the roadway facilities, and the latter is typically a broader integration of a larger pool of related activities, like transit, parking, and driver-behavior elements. ATM enhancements involve some sort of “smart highway” feature that uses real-time speed, vehicle-count, or even vehicle-occupancy data to open or close certain lanes, adjust the speeds on the mainlines, or vary the candidacy to even be in certain lanes (e.g., HOV, HOT, truck-only, etc.) in the first place.
Nonrecurring Congestion Program Strategies
Traffic Incident Management. This utilizes a combination of public safety functions and traffic management functions – it requires cooperation between various public agencies to reduce congestion by clearing traffic crashes and removing stalled vehicles. FHWA is championing laws, policies, and practices that speed up the clearance of major and minor incidents that create congestion.
Work Zone Management. This program is working to “make work zones work better” by providing transportation practitioners with high-quality products, tools, and information that can be of value in planning, designing, and implementing safer, more efficient, and less congested work zones.
Road Weather Management. This program seeks to better understand the impacts of weather on roadways, and promote strategies and tools to mitigate those impacts.
Highways for LIFE. Highways for LIFE is all about building faster, safer, with better quality, less cost, and causing less work zone congestion. The purpose of Highways for LIFE (HfL) is to advance longer-lasting highway infrastructure using innovations to accomplish the fast construction of efficient and safe highways and bridges. The three goals of HfL are to improve safety during and after construction, reduce congestion caused by construction, and improve the quality of the highway infrastructure.
The Localized Bottleneck Reduction Program – Focus on Recurring Congestion
In concert with the above focus areas, FHWA’s Localized Bottleneck Reduction (LBR) Program is entirely aimed at reducing recurring congestion. The LBR Program promotes operational and low-cost bottleneck mitigation strategies to improve mobility at specific locations. Managed by the Office of Operations, the program serves to bring attention to the root causes, impacts, and potential solutions to traffic chokepoints that are recurring events; ones that are wholly the result of operational influences. The goal of the program is to raise awareness of bottlenecks at the state level and promote low-cost, quick-to-implement geometric and operational improvements to address recurring chokepoints. The LBR Program has several activities underway, including:
- This Primer, which is in its third iteration, providing an overview of the wide range of operational and low-cost strategies available to reduce congestion at bottlenecks and provides guidance for agencies implementing LBR programs;
- A compendium of state best practices in bottleneck identification, assessment, countermeasures, and evaluation, including how bottlenecks are treated in the annual planning and programming processes;
- Version X of the Traffic Analysis Toolbox which focuses on focusing on what analysis tools are available, necessary and productive for localized congestion remediation; and
- State-specific workshops for state and local agencies to learn and share information on localized bottleneck reduction strategies and how they can be incorporated into their respective planning processes.
Benefits of Localized Bottleneck Improvements
The LBR Program focuses on operationally influenced bottlenecks – small, localized “hot spots” where the design of the roadway itself becomes the constricting factor in processing traffic demand, resulting in recurring delays of generally predictable times and durations. Megaprojects required to resolve major bottleneck problems and systemic congestion (e.g., entire corridor rebuilds, multimile lane additions, and systemwide improvements) are far and above the focus of this program area. Unfortunately, when weighed against these larger, more visible projects, localized bottleneck problems often receive lower priority for funding or are put off entirely until they can be implemented as part of the larger, all-encompassing project. However, in this day and age of fiscal constraints, with agencies facing over-escalating costs and increasingly limited right-of-way, it is evident that “business as usual” in resolving congestion problems no longer applies. Low-cost bottleneck mitigations have several advantages that can help agencies deal with these developments:
- They address current problems and therefore have high visibility. Agencies are under increasing pressure to do something immediately about congestion problems. Because low-cost bottleneck treatments are small in scale, they can be implemented quickly, so benefits start accruing immediately.
- They are highly cost-effective and usually have positive safety impacts. Low-cost bottleneck treatments could mitigate or reduce crashes within weaving and merging areas, thereby increasing the cost-effectiveness relative to safety merits.
- They will be required as transportation funding for megaprojects becomes more constrained. Major reconstruction projects are often justified as the only valid solutions to relieve congestion at the worst bottleneck locations. However, the cost of executing such projects is usually enormous. Low-cost bottleneck improvements provide an effective way to stretch scarce resources.
- Lower cost means more locations can be addressed. More spot solutions can be implemented throughout a region, addressing more corridors than just a few large projects.
- They are less invasive on the physical and human environments. The environmental footprint of low-cost bottleneck projects is very low, both in terms of disruptions during construction and final design.
- They are not necessarily just short-term fixes. For some low-cost treatments, congestion benefits will play out over many years, not just a few. In fact, when combined with other forms of treatment (e.g., demand management and operations), they may be part of a long-term solution for a problem location or corridor.
- They may be considered part of major reconstruction projects to address current problems. Some state DOTs have successfully incorporated low-cost bottleneck treatments within the context of larger, multiyear reconstruction projects.