Introduction

The Energy Policy Act of 1992 (EPACT) directed the EIA to establish a data collection program of use to those seeking to enter the market for alternative-fuel vehicles and their fueling facilities. Two critical areas of understanding concerning these emerging markets are the total U. S. vehicle market in which alternative-fuel vehicles would have to compete and the nature of the vehicles that they might replace. Therefore, EIA determined to assess the composition of the total U.S. vehicle stock.

Many vehicle data sources exist, each of which has collected data for distinct groups with specific needs. Together, these data sources provide information that is somewhat limited and often not comparable. Measuring and dissecting the entire U.S. vehicle stock based upon analysis of the existing collections of vehicle data are complicated by the following:

• The data sources that produce definitive estimates on the vehicle stock (those data sources that use State vehicle registration data as a base for estimation) include residential vehicles in their total count, and they do not distinguish the residential vehicles from the nonresidential.
• Different data sources are generally prepared for very different purposes. Consequently, each source has its own scope, target population, relative data of interest, and methodology.
• The data sources are of varied degrees of completeness and/or have different reference periods.
• Many data sources use additional, contributing information from other sources; unclear relationships and circular
  logic often arise.
  

Perhaps the most intriguing aspect of the U.S. vehicle stock is that there are nearly fourteen to sixteen million nonresidential vehicles for which no data source can account. The estimate of the expected number of nonresidential vehicles is much larger than the number that can be identified in the major nonresidential vehicle markets. In other words, there exists a gap 1
between how many nonresidential vehicles there should be and how many nonresidential vehicles have been accounted for. This study provides some plausible, but not documented, conjectures regarding the discrepancy. Additionally, some data from local areas have been extrapolated to derive estimates that represent the entire United States. Because of the
uncertainty involved with some data sources and the theoretically unsupported nature of inferring by projecting or extending estimated values without sound statistical basis, this study should be viewed as a speculative attempt to quantify the U.S. vehicle stock.

Contact:

Stephanie.battle@eia.doe.gov

Stephanie Battle

Phone: (202) 586-7237

Fax: (202) 586-0018

URL: http://www.eia.gov/emeu/altfuelvh/stock2a.html
File Last Modified: June 17, 1998