Citation

Reust T, Morgan J. Collision 2007; 2(2): 32-40.

Copyright

(Copyright © 2007, Collision Publishing)

DOI

unavailable

PMID

unavailable

Abstract

This paper builds on previous research on the accuracy of speed recorded by a sensing diagnostic module (SDM) and the effects of factors such as brake and yaw. The previous paper compared calibrated speed to the SDM-reported speed from more than 80 tests on dry roadways using different types of vehicles with instrumentation. The current paper provides more details on the test findings, including yaw rates and lateral acceleration values for some of the yaw tests. Findings show that the accuracy of the SDM-speed during low and normal acceleration is approximately ± 1.5 mph. The accuracy is approximately ± 1.5 mph during maximum acceleration at full throttle, except during initial takeoff and manual gear shift. The accuracy is approximately +0.5 to -2.0 mph during coasting. When a vehicle is in a yaw, the SDM-reported speed is underreported by approximately 2-7% when only steering has been used and is underreported by approximately 3-18% when both steering and braking have been used at SDM-reported speeds of 30 mph and higher. During maximum brake application and when the antilock brake system is activated, the SDM-reported speed is underreported by approximately 8-18% at SDM-speeds of 30 mph and higher.