ATDM Program Brief: Active Traffic Management
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What is Active Transportation and Demand Management (ATDM)?
ATDM is the dynamic management, control, and influence of travel demand, traffic demand, and traffic flow of transportation facilities. Through the use of available tools and assets, traffic flow is managed and traveler behavior is influenced in real-time to achieve operational objectives, such as preventing or delaying breakdown conditions, improving safety, promoting sustainable travel modes, reducing emissions, or maximizing system efficiency. Under an ATDM approach, the transportation system is continuously monitored. Using archived data and or/predictive methods, actions are performed in real-time to achieve or maintain system performance. This brief focuses on the active traffic management component of ATDM.
Active management of transportation and demand can include multiple approaches spanning demand management, traffic management, parking management, and efficient utilization of other transportation modes and assets. Some example approaches are included in the table. Those highlighted in yellow are the focus of this brief.
What is Active Traffic Management?
Active traffic management (ATM) is the ability to dynamically manage recurrent and non-recurrent congestion based on prevailing and predicted traffic conditions. Focusing on trip reliability, it maximizes the effectiveness and efficiency of the facility. ATM approaches seek to increase throughput and safety through the use of integrated systems with new technology, including the automation of dynamic deployment to optimize performance quickly and without delay that occurs when operators must deploy operational strategies manually. In addition to the approaches listed in the table, ATM includes dynamic routing, dynamic junction control, adaptive signal control, and transit signal priority. These approaches can be described thus:
What are the key concepts of ATM?
Fundamental concepts of ATM are active management of the capacity and the direct interaction with the driver to encourage them to make tactical decisions in vehicle or driver performance (e.g., stopping, slowing down, changing lanes). The idea is not to simply react to changing conditions but to anticipate them and actively manage the system prior to their occurrence. All agencies and entities operating transportation systems can advance towards a more active management philosophy by making changes that move operations along the active management continuum. An example of temporary shoulder use being applied along the active management continuum shown in Figure 1.
At the lowest level in the continuum, agencies are mostly engaged in monitoring their existing lanes and infrastructure with the shoulders not being used as travel lanes. As agencies move up in the continuum, they could adjust supply on the facility by using shoulders as lanes during peak hours. This level can include such strategies as hard shoulder running, lane control, and improved ramp metering. Further along the active continuum, agencies can open or close shoulder lanes based on demand and can include strategies such as local adaptive ramp metering, responsive lane control, and shoulder use due to an incident or planned special event. The final level in the active management continuum includes 24/7 shoulder operations using current and predictive levels of traffic and incidents. To reach the highest level of active management, an agency needs a combination of technologies, resources, policies, procedures, and public acceptance. Furthermore, an agency may need to work through several iterations along the continuum before reaching the highest level. A similar continuum can be mapped for each of the strategies under ATM. Furthermore, ATM strategies are often complementary and can be more effective when combined to meet multiple objectives at the same time.
U.S. Examples of ATM
Figure 4 shows some of the locations across the United States which have implemented some form of ATM on their transportation system. The table on the following page highlights some key ATM projects either in operation or under development. As shown, the various approaches to ATM have been implemented to dynamically manage lane use, speed limits, and ramp access.
Agencies can realize numerous benefits with active traffic management. General operational benefits include:
Specific identifiers that may indicate whether or not ATM strategies should be implemented and produce desirable benefits include:
ATDM Project Informational Briefs
This informational brief is one of the ATDM briefs in the Program category of the FHWA ATDM Briefs Series. ATDM briefs are or will be available in the categories of:
For more information:
Publication #: FHWA-HOP-13-003
United States Department of Transportation - Federal Highway Administration