Abstract
Automobile fuel economy derived from tests varies greatly from that obtained from actual daily use. This 'gap' appears to be growing because tests do not reflect real-world driving and because driving is increasingly becoming less fuel-efficient. Comparisons among the US, Canada and four European countries find that automobile fuel economy tests tend to understate fuel use by 15-25%. Since automobile fuel use is at the center of much environmental concern, the present analysis of new-car fuel economy suggests some mitigation techniques to close the test/actual fuel economy gap. (Author/publisher).