NCJ Number
232587
Journal
Journal of Forensic Sciences Volume: 55 Issue: 5 Dated: September 2010 Pages: 1347-1351
Date Published
September 2010
Length
5 pages
Annotation
This article describes two approaches as to how to derive the measurement of velocity of an allegedly speeding vehicle.
Abstract
Sometimes the question arises whether it is possible to estimate the velocity of a speeding car recorded by closed circuit television cameras. By estimating the travelled distance of the car between two images and the time elapsed, estimation of the velocity is rather straightforward. However, to quantify the corresponding measurement uncertainty, the data analysis becomes more involved. The article describes two approaches as to how to derive the measurement uncertainty. In the first method, distance and timing are estimated separately, and the two uncertainties are combined to derive the measurement uncertainty for the velocity. For this, a frequentist and a Bayesian approach are described. In the second method, the measurement uncertainty for the speed is derived directly using validation recordings of a car driving by at known speed. The choice which method to use depends mainly on the length of the path that the car has travelled. (Published Abstract)