Congestion Mitigation

Traffic Congestion Challenges

Demand for highway travel by Americans continues to grow as population increases, particularly in metropolitan areas. Construction of new highway capacity to accommodate this growth in travel has not kept pace. Between 1980 and 1999, route miles of highways increased 1.5 percent while vehicle miles of travel increased 76 percent. The Texas Transportation Institute estimates that, in 2000, the 75 largest metropolitan areas experienced 3.6 billion vehicle-hours of delay, resulting in 5.7 billion gallons in wasted fuel and $67.5 billion in lost productivity. And traffic volumes are projected to continue to grow. The volume of freight movement alone is forecast to nearly double by 2020. Congestion is largely thought of as a big city problem, but delays are becoming increasingly common in small cities and some rural areas as well.

Causes of Traffic Congestion

Simply, highway congestion results when traffic demand approaches or exceeds the available capacity of the highway system. While this is a simple concept, it is not constant. Traffic demands vary significantly depending on the season of the year, the day of the week, and even the time of day. Also, the capacity, often mistaken as constant, can change because of weather, work zones, traffic incidents, or other non-recurring events.

From a combination of recent studies and analytical work, it is estimated that roughly half of the congestion experienced by Americans is what is known as recurring congestion—caused by recurring demands that exist virtually every day, where road use exceeds existing capacity.

The other half is due to non-recurring congestion caused by temporary disruptions. The four main causes of non-recurring congestion are: traffic incidents (ranging from disabled vehicles to major crashes), work zones, weather, and special events. Non-recurring events dramatically reduce available capacity and reliability of the entire transportation system. Travelers and shippers are especially sensitive to the unanticipated disruptions to tightly scheduled personal activities and manufacturing distribution procedures.

Solutions

FHWA is focusing its efforts on addressing both the recurring and non-recurring portions of the traffic congestion problem. In addition to providing substantial assistance to State and local transportation agencies as they develop projects to increase capacity and remove bottlenecks, FHWA is also focusing on short-term initiatives to mitigate congestion through effective system management and operations strategies. FHWA has designated congestion mitigation as one of its “vital few” priorities and is focusing resources on developing and sustaining regional partnerships to address all aspects of congestion and working to reduce two of the most prevalent causes of traffic congestion: work zones and traffic incidents.

How is the congestion pie sliced?

Total Delay: about 4 billion hours per year.

In the congestion partnership area, we are helping our State and local transportation partners develop regional frameworks for the integrated deployment of intelligent transportation systems technology, such as traffic conditions monitoring, computerized traffic control systems, traveler information systems, and public transit information management systems. We are helping to facilitate the nationwide deployment of the 511 traveler telephone number, and we are developing and delivering guidance and training to help State and local agencies focus more on regional operations collaboration and coordination activities. These activities include the definition of local congestion and system performance problems, solutions, and measures, and adoption and implementation of strategies that cross-jurisdictional boundaries such as coordinated signal timing.

With regard to reducing delay caused by traffic incidents, we are working with each of the 75 largest metropolitan areas to identify effective strategies to reduce delay caused by traffic incidents. We are developing detailed technical guidance and training and other assistance tools focused on developing and implementing formal traffic incident management programs that can improve congestion by reducing the time to detect, respond to, and clear incidents. Implementation of these multi-agency programs involving transportation, public safety and private sector partners have typically shown that the duration of major incidents can be reduced 40 percent or more.

In the work zone traffic management area, we are working with each of the States to identify effective strategies to reduce delay caused by work zones. The implementation of work zone mobility strategies such as working at night or during off-peak hours, using innovative materials and construction techniques to reduce construction times, and using technology to provide timely information to travelers can significantly reduce delays caused by work zones. For example, State transportation professionals in Ohio have implemented weekend and total closures as a strategy to accelerate work and minimize motorist delay. This practice of totally closing a section of roadway for a period of time while rerouting traffic has been extensively used in the reconstruction of the Spring-Sandusky Interchange. The benefit of this strategy is that it allows the contractor to work more safely and efficiently without traffic in the work zone, and it reduces the cost and total time to construct the project.

For more information on FHWA Congestion Mitigation activities, please visit the FHWA Congestion Mitigation web site at http://www.fhwa.dot.gov/congestion, the ITS Joint Program Office web site at http://www.its.dot.gov, or the Office of Operations web site at http://www.ops.fhwa.dot.gov.





Search: Home About Us Office Directory Program Areas Regulation/Policy Publications Speeches Press Room Links Site Index Feedback	Congestion Mitigation Program Areas > Reducing Recurring Congestion / Reducing Non-Recurring Congestion Traffic Congestion Challenges Demand for highway travel by Americans continues to grow as population increases, particularly in metropolitan areas. Construction of new highway capacity to accommodate this growth in travel has not kept pace. Between 1980 and 1999, route miles of highways increased 1.5 percent while vehicle miles of travel increased 76 percent. The Texas Transportation Institute estimates that, in 2000, the 75 largest metropolitan areas experienced 3.6 billion vehicle-hours of delay, resulting in 5.7 billion gallons in wasted fuel and $67.5 billion in lost productivity. And traffic volumes are projected to continue to grow. The volume of freight movement alone is forecast to nearly double by 2020. Congestion is largely thought of as a big city problem, but delays are becoming increasingly common in small cities and some rural areas as well. Causes of Traffic Congestion Simply, highway congestion results when traffic demand approaches or exceeds the available capacity of the highway system. While this is a simple concept, it is not constant. Traffic demands vary significantly depending on the season of the year, the day of the week, and even the time of day. Also, the capacity, often mistaken as constant, can change because of weather, work zones, traffic incidents, or other non-recurring events. From a combination of recent studies and analytical work, it is estimated that roughly half of the congestion experienced by Americans is what is known as recurring congestion—caused by recurring demands that exist virtually every day, where road use exceeds existing capacity. The other half is due to non-recurring congestion caused by temporary disruptions. The four main causes of non-recurring congestion are: traffic incidents (ranging from disabled vehicles to major crashes), work zones, weather, and special events. Non-recurring events dramatically reduce available capacity and reliability of the entire transportation system. Travelers and shippers are especially sensitive to the unanticipated disruptions to tightly scheduled personal activities and manufacturing distribution procedures. Solutions FHWA is focusing its efforts on addressing both the recurring and non-recurring portions of the traffic congestion problem. In addition to providing substantial assistance to State and local transportation agencies as they develop projects to increase capacity and remove bottlenecks, FHWA is also focusing on short-term initiatives to mitigate congestion through effective system management and operations strategies. FHWA has designated congestion mitigation as one of its “vital few” priorities and is focusing resources on developing and sustaining regional partnerships to address all aspects of congestion and working to reduce two of the most prevalent causes of traffic congestion: work zones and traffic incidents. How is the congestion pie sliced? Total Delay: about 4 billion hours per year. In the congestion partnership area, we are helping our State and local transportation partners develop regional frameworks for the integrated deployment of intelligent transportation systems technology, such as traffic conditions monitoring, computerized traffic control systems, traveler information systems, and public transit information management systems. We are helping to facilitate the nationwide deployment of the 511 traveler telephone number, and we are developing and delivering guidance and training to help State and local agencies focus more on regional operations collaboration and coordination activities. These activities include the definition of local congestion and system performance problems, solutions, and measures, and adoption and implementation of strategies that cross-jurisdictional boundaries such as coordinated signal timing. With regard to reducing delay caused by traffic incidents, we are working with each of the 75 largest metropolitan areas to identify effective strategies to reduce delay caused by traffic incidents. We are developing detailed technical guidance and training and other assistance tools focused on developing and implementing formal traffic incident management programs that can improve congestion by reducing the time to detect, respond to, and clear incidents. Implementation of these multi-agency programs involving transportation, public safety and private sector partners have typically shown that the duration of major incidents can be reduced 40 percent or more. In the work zone traffic management area, we are working with each of the States to identify effective strategies to reduce delay caused by work zones. The implementation of work zone mobility strategies such as working at night or during off-peak hours, using innovative materials and construction techniques to reduce construction times, and using technology to provide timely information to travelers can significantly reduce delays caused by work zones. For example, State transportation professionals in Ohio have implemented weekend and total closures as a strategy to accelerate work and minimize motorist delay. This practice of totally closing a section of roadway for a period of time while rerouting traffic has been extensively used in the reconstruction of the Spring-Sandusky Interchange. The benefit of this strategy is that it allows the contractor to work more safely and efficiently without traffic in the work zone, and it reduces the cost and total time to construct the project. For more information on FHWA Congestion Mitigation activities, please visit the FHWA Congestion Mitigation web site at http://www.fhwa.dot.gov/congestion, the ITS Joint Program Office web site at http://www.its.dot.gov, or the Office of Operations web site at http://www.ops.fhwa.dot.gov.
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