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Air Quality Planning for Transportation Officials

Transportation Control Measures

Of the control strategies States may choose to implement, some may be on-road mobile source measures to reduce vehicle use or change traffic flow or congestion conditions. These measures are known as transportation control measures (TCMs). A TCM is any measure that is specifically identified in the SIP for the purpose of reducing emissions or concentrations of air pollutants from transportation sources.

Transportation agencies have the most thorough knowledge of the feasibility of many of the different types of transportation programs and projects that can be implemented in their area. Transportation control measures should be developed through both the transportation and air quality planning processes to insure future implementation. Transportation agencies will be held accountable for the implementation of TCMs from SIPs in the development of future transportation plans.

The SIP must provide for the implementation and enforcement of TCMs. TCMs should be developed jointly by transportation and air agencies as part of the transportation planning process, and incorporated into the SIP. In addition, many transportation plans and TIPs include TCM-like projects such as transit investments or HOV lanes, which are not included in the SIP. These measures can help improve air quality but are not considered legally enforceable commitments unless they are identified as TCMs in the SIP.

TCMS that are identified in the CAA include:

Updated: 8/4/2015
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