Transportation Control Measures

Background

Transportation accounts for 33 percent of carbon dioxide (CO2) emissions and produces numerous other toxic pollutants that are dangerous to human health. TCMs are activities that attempt to change aspects of present transportation practices to reduce these harmful effects.

Section 108 of the Clean Air Act, as amended in 1990, lists 26 activities that qualify as transportation control measures, including improved public transit, creation of high occupancy vehicle (HOV) lanes, improving access for pedestrians and cyclists, creating measures to curb extended vehicle idling, and creating programs to encourage voluntary removal of pre-1980 vehicles from the roads and the marketplace.

Specific programs can also qualify as TCMs if they are committed to in State Implementation Plans (SIPs) or will reduce transportation-related emissions by fostering improvements in traffic flow or reductions in vehicle use.

The Intermodal Surface Transportation Efficiency Act (ISTEA), passed in 1991, funds transportation projects and programs intended to assist regions in meeting ambient air quality standards. The CMAQ Improvement Program was established under ISTEA, and CMAQ is apportioned to states that then allocate funds within the state.

CMAQ projects are intended to produce measurable reductions in dangerous emissions products, including particulate matter (PM), nitrogen oxides (NOx), carbon monoxide (CO), and volatile organic compounds (VOCs). However, for purposes of evaluating the effects of a TCM program, results can be described in terms of changes in travel patterns (for example, reduced person-trips or time of day of travel), reductions in vehicle activity (for example, total vehicle trips or total vehicle miles of travel), changes in traffic flow characteristics (for example, travel speeds), and changes in vehicle activity and traffic flow resulting in changes in emissions.

Public Transportation

One major class of TCMs involves encouraging the use of public transportation by providing available, affordable, convenient, and reliable services, and [Page 1509]using public information campaigns to make the population aware of the services available and the benefits of using public transportation. Examples of programs to encourage transit use include the creation of dedicated bus lanes to speed travel, park-and-ride facilities, and discount-fare or other incentive programs, as well as upgrading transit vehicles and shelters. The use of public transportation reduces emissions and fuel use, while also reducing congestion and improving traffic flow. Transit may also provide a better experience to the rider. For example, it is possible to read while riding the bus or train, and it is not necessary to pay attention to the road.

...