[1] NVTC estimate from district fuel tax collections and 2003 World Almanac.

[2] Conserving Energy and Preserving the Environment:  The Role of Public Transportation, Robert J. Shapiro, Kevin A. Hassett and Frank Arnold (July, 2002).

[3] Ibid.

[4] 2001 Urban Mobility Study, Texas Transportation Institute (May, 2001).

[5] Fiscal Impact of Metrorail on the Commonwealth of Virginia, KPMG Peat Marwick, (November, 1994).

[6] Table 10 in 1999 Performance of Regional HOV Facilities on Freeways in the Washington Region. Final Draft. October 6, 2000. Methodology: Sum of observed person movements in the A.M. peak period for I-395, I-66, and VA 267.

[7] TR News.  Transportation Research Board, National Research Council.  Number 214: (May-June 2001). 

[8] HOV, or high occupancy vehicle, refers to those non-transit vehicles carrying two or more persons (autos, SUVs, pickup trucks, and vans). SOV, or single-occupancy vehicle is an auto or auto-like vehicle carrying exactly one person (the driver).

[9] Note:  The actual proportions of SOV vehicles observed on the particular roadway are higher as some of the corridor transit service, such as Metrorail and VRE, is provided outside the roadway.

[10] 1999 Performance of Regional High-Occupancy Vehicle Facilities on Freeways in the Washington Region: An Analysis of Travel Times. Final Draft. National Capital Region Transportation Planning Board of the Metropolitan Washington Council of Governments (October 6, 2000). A measurement of the standard deviation of elapsed travel times.

[11] The 2002 Urban Mobility Report. Texas Transportation Institute (June 2002).

[12] The TTI methodology factors in peak period travel under all traffic conditions, including incidents, over a longer length of the corridor compared to the COG/TPB study of HOV performance.

[13] TR News. Transportation Research Board, National Research Council. Number 214: (May-June 2001).