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Transportation Conformity: A Basic Guide for State and Local Officials

Appendix B Options to Reduce Emissions from On-road Motor Vehicles

The CAA identifies actions (transportation control measures or TCMs) that may be taken to reduce emissions from mobile sources9. In addition, there are other measures such as vehicle controls, fuel-based standards, and inspection and maintenance programs that may also help areas reduce mobile source emissions. While some of the measures are not the responsibility of State and local transportation officials, it is beneficial for officials to be familiar with on-road motor vehicle control programs implemented by other public agencies (e.g., motor vehicle departments, environmental agencies), automobile manufacturers and fuel suppliers. Having an understanding of the costs and benefits of all available options to achieve emission reductions is useful to officials in advance of being asked to make decisions on specific strategies for implementation.

TransportatIon Control Measures

Options to control and reduce emissions from motor vehicles comes under the category of TCMs. Implementation of these measures is typically within the purview of transportation agencies, and TCMs are usually funded with FHWA/FTA or State and local transportation funds. The emission reduction potential of conventional TCMs, such as ridesharing and bicycling programs is not likely to be as substantial as the technology-based transportation measures discussed above. Nevertheless, TCMs can be useful in reducing congestion and may be needed in some areas in order to demonstrate attainment of the NAAQS. TCMs such as expanded transit services can also provide and enhance travel options and increase travel choices.

The CAA requires that in ozone nonattainment areas classified as severe or extreme, the State must identify and adopt specific transportation control strategies and TCMs to offset any projected growth in emissions from growth in vehicle miles traveled. States and MPOs should consider the CAA list of TCMs (Section 108(F)(1)(A)) for strategies they might include in the SIP. These 16 TCMs (with the exception of programs to encourage the removal of pre-1980 vehicles) are eligible for Congestion Mitigation and Air Quality Improvement (CMAQ) Program funding. Below is the list of TCMs included in the CAA. There is overlap between some of the measures and the descriptions listed illustrate types of projects that might be considered in nonattainment areas to reduce mobile source emissions or to increase overall vehicle occupancy.

CAA SectIon 108(F)(1)(A) TransportatIon Control Measures Include

  1. programs for improved public transit;
  2. restriction of certain roads or lanes to, or construction of such roads or lanes for use by, passenger buses or high-occupancy vehicles (HOV);
  3. employer-based transportation management plans, including incentives;
  4. trip-reduction ordinances;
  5. traffic flow improvement programs that achieve emissions reductions;
  6. fringe and transportation corridor parking facilities serving multiple-occupancy vehicle programs or transit service;
  7. programs to limit or restrict vehicle use in downtown areas or other areas of emission concentration particularly during periods of peak use;
  8. programs for the provision of all forms of high-occupancy, shared-ride services;
  9. programs to limit portions of road surfaces or certain sections of the metropolitan area to the use of non-motorized vehicles or pedestrian use, both as to time and place;
  10. programs for secure bicycle storage facilities and other facilities, including bicycle lanes, for the convenience and protection of bicyclists, in both public and private areas;
  11. programs to control extended idling of vehicles;
  12. reducing emissions from extreme cold-start conditions;
  13. employer-sponsored programs to permit flexible work schedules;
  14. programs and ordinances to facilitate non-automobile travel, provision and utilization of mass transit, and to generally reduce the need for single-occupant vehicle travel, as part of transportation planning and development efforts of a locality, including programs and ordinances applicable to new shopping centers, special events, and other centers of vehicle activity;
  15. programs for new construction and major reconstruction of paths, tracks, or areas solely for use by pedestrian or other non-motorized means of transportation when economically feasible and in the public interest. For purposes of this clause, the Administrator shall also consult with the Secretary of the Interior;
  16. programs to encourage removal of pre-1980 vehicles.

9 CAA Section 108(f)

Market-based TransportatIon Control Measures

In addition to conventional TCMs, work is underway in nonattainment areas to explore options to reduce mobile source emissions using market-based TCMs such as road pricing, congestion pricing, vehicle miles of travel (VMT) fees, and parking pricing. These mechanisms can be relatively cost-effective and can be designed to impact vehicles at either certain times of the day (e.g., peak-period pricing), or at all times. In addition, these measures in combination with traditional TCMs have the potential to address other public policy objectives such as congestion reduction and energy conservation.

In many areas public acceptance of market-based TCMs has been slow due to practical and political considerations. For example, implementation of market-based measures may require State legislation (e.g., congestion pricing) or a voter referendum. Therefore, regardless of the potential merits and cost-effectiveness of these measures, the implementation of market-based TCMs is likely to occur gradually.

Updated: 03/14/2012
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