Study: CSA Data Does Not Predict Crash Performance
Posted: August 1, 2014
The Alliance for Safe, Efficient, and Competitive Truck Transportation (ASECTT) released a study that says safety data under the new Compliance, Safety, Accountability (CSA) does not accurately predict crashes.
ASECTT asked Dr. Inam Iyoob, an engineer with Transplace, to review the Federal Motor Carrier Safety Administration’s (FMCSA) defense of SMS methodology as a valid predictor of carrier safety.
In his four page report, Iyoob says that “with respect to individual carriers, percentile rankings both above and below the arbitrary “monitoring thresholds” […] are not valid predictors of crash frequency.”
FMCSA’s data, Iyoob writes, cannot be used to predict the crash performance of individual carriers “even though the FMCSA says SMS scores are correlated to the average crash frequency of hundreds of carriers at each percentile integral.”
“Consumers of freight transportation do not select “average” carriers, they select individual carriers and the Agency study offers no proof that SMS methodology is a predictor of individual carrier safety performance at any percentile level.”
Iyoob writes that he can’t see “any useful purpose in averaging crash data of hundreds of carriers in each of 100 different percentiles and then calculating a regression of the average values.
“The purpose of regression analysis is to explain variation. Averaging hundreds of carriers at each percentile eliminates most of the variation in the data. It is not statistically accurate to say the SMS methodology and BASIC percentile scores are an accurate predictor of carrier safety predicated upon the crash data the agency uses to justify its conclusions.”
Iyoob says that logically, unsafe driving and driver fatigue do impact crashes, the manner in which the SMS BASICs Unsafe Driving and Fatigued Driving are collected, calculated and interpreted does not show any correlation to crashes.
“Hence usage of SMS data for carrier selection will unduly favor some and penalize others, and thus should be avoided.”
ASECTT is a nonprofit corporation formed for the purpose of ensuring a balanced regulatory approach to highway safety. You can read the study here.