15.5.1 Active Transportation and Demand Management (ATDM) Strategies
FHWA defines ATDM as the dynamic movement, control, and influence of travel demand, traffic demand, and traffic flow on transportation facilities. ATDM is part of the broader concept of TSMO, with a deeper focus on the active management principle of TSMO and combining ATDM strategies. The ATDM analysis methodology in the 7th Edition of the HCM distinguishes between five principal categories of strategies that may affect facility operations:
- Demand Management Strategies– These strategies alter the entire system of segments and analyses when they are used in the event of an increase or decrease in demand.
- Weather Management Strategies– These strategies only impact performance during analysis periods when a severe weather event affects the facility and apply equally to all segments. For example, weather-related driver information, snow removal, flood closures, etc.
- Incident Management Strategies– These strategies only impact the performance of segments and analysis periods when an incident occurs. For example, freeway service patrol, driver information, dynamic lane assignment, etc.
- Work Zone Management Strategies– These strategies only impact the performance of segments and analysis periods when a work zone is present. For example, end-of-queue warning system, dynamic merge control, etc.
- Special Segment-Specific Strategies– These are the strategies not covered in the previous categories. These strategies impact the performance of specific target segments. For example, ramp metering, hard shoulder running, etc