# Appendix C Sources of Default Parameter Values

The following is list of sources for the default parameter values used
in STEAM.

Value of Time -- In-vehicle time from US DOT Memorandum dated April 9,
1997 on Departmental Guidance for Valuation of Travel Time in Economic
Analysis. Out-of-vehicle time from Federal Transit Administration,
[Technical Guidance on Section 5309 New Starts Criteria]{.underline} ,
September 1997.

Cost Per Gallon of Fuel -- Average prices in 1997.

Non-fuel vehicle operation cost -- USDOT [Characteristics of Urban
Transportation Supply,]{.underline} 1992. Costs in 1997 dollars.

Fuel Consumption Rates -- Cohn, Louis, Roger Wayson, and Roswell,
"Environmental and Energy Considerations". [Transportation Planning
Handbook.]{.underline} Institute of Transportation Engineers. 1992.
Urban fuel consumption procedures were used. Auto rates were multiplied
by correction factor to convert from 1980 rate to 2005 rate.

Emission Rates for Hot Stabilized Mode: See Appendix D for HC, NOx and
CO. For PM10, estimates exclude fugitive dust , and are based on EPA's
Emission Trends Report by E. H. Pechan. The PART5 model was run to
produce 2010 estimates. Trucks were assumed to be heavy duty diesel
vehicles only, and have the same rate as buses.

Cost Per Ton of Emissions -- Wang, M. and Santini, D. "Monetary Values
of Air Pollutant Emissions in Various U.S. Areas". [Transportation
Research Record No. 147]{.underline}5. TRB. 1995. The costs for Denver
was used for HC, NOx and CO, adjusted from 1989 dollars to 1997 dollars
using relevant Consumer Price Indices. For PM10, lower bound costs,
adjusted to 1997 dollars, were used from Mark Delucchi, [The Annualized
Social Cost of Motor Vehicle Use in the U.S., 1990-1991: Summary of
Theory, Data, Methods, and Results.]{.underline} Institute of
Transportation Studies, Davis, CA. June 1997.

Emissions Per Cold Start -- See Appendix D for HC, CO, and NOx.

Cold Starts Per Trip -- Venigalla, Mohan, Terry Miller and Arun
Chatterjee. "Start Modes of Trips for Mobile Source Emissions Modeling.
[Transportation Research Record No. 1432]{.underline}. TRB. 1994.

Greenhouse Gas Emissions -- Federal Transit Administration, [Technical
Guidance on Section 5309 New Starts Criteria]{.underline} , September
1997.

Cost Per Accident -- The Urban Institute, [The Cost of Highway
Crashes]{.underline}, prepared for FHWA. October 1991., and FHWA,
[Federal Highway Cost Allocation Study]{.underline}; 1997 (Chapter V)
for breakdown between internal and external components. For urban
highways, the external portion is estimated in the HCAS as 1.26 cents
per vehicle mile out of a total of 9 cents per vehicle mile. This
amounts to 14%. The assumption is that all costs borne by users are
internalized and perceived by the highway user. The STEAM user should
use an external cost percentage reflecting the proportion of total
accident costs that are not recognized by highway users (whether or not
they bear the costs), and therefore not considered in driving decisions.

Accident Rates:

Fatality Rates - FHWA, [Highway Safety Performance]{.underline} - 1992,
January 1995.

Injury Rates - FHWA, [Highway Safety Performance]{.underline} - 1992,
January 1995.

PDO Crash Rates - NHTSA, [Traffic Safety Facts]{.underline}, 1993.

Noise Costs - FHWA, [Federal Highway Cost Allocation Study]{.underline};
Appendix E, 1997.

Discount Rate -- Federal Office of Management and Budget. [Benefit-Cost
Analysis of Federal Programs: Guidelines and Discounts. Circular A-94
revised.]{.underline} Federal Register, November 10, 1992.

Risk Ranges - Cambridge Systematics research team judgement.

Federal and State Fuel Tax Rates - FHWA, [Highway
Statistics]{.underline} - 1995, Table MF-121T.