@article{ref1,
title="Safety experience of large trucks: an analysis of sample size requirements",
journal="Journal of the transportation research forum",
year="1988",
author="Sparks, G. and Horosko, A. and Smith, Alastair",
volume="29",
number="1",
pages="24-27",
abstract="Considerable debate has emerged in Canada in terms of the relative safety of different types of large trucks (i.e., double trailer units versus single trailer units; A-Train versus B-Train versus C-Train configurations, etc.).  This paper presents an analysis of the sample size required in order to have a reasonable expectation of detecting statistically significant differences in safety experience for varying levels of actual differences in accident rates. The results indicate that the sample size required to detect a 10-20% difference in (actual) accident rates is in the order of 1-2 x 10 to the 9th power vehicle kms of travel. Smaller samples could only be expected to detect larger actual differences.  These results suggest that:  (1) it is very important to include an appropriate statistical analysis as part of accident research analysis if differences in the order of 20% are of interest; and (2) the value of much of the research reported on the relative safety experience of various vehicle types may be limited and/or questionable because of limited sample sizes and/or the lack of appropriate statistical analysis.<p />",
language="",
issn="1046-1469",
doi="",
url="http://dx.doi.org/"
}