A new study says the Federal Motor Carrier Safety Administration's safety data under its new Compliance, Safety, Accountability (CSA) program does not accurately predict crashes.

The Alliance for Safe, Efficient, and Competitive Truck Transportation commissioned a study on the correlation between individual carrier percentile rankings and crash frequency based on data obtained from the FMCSA's data bank.

The study shows that, with respect to individual carriers, percentile rankings of carriers both above and below the arbitrary "monitoring thresholds" indicated with the alert symbol (a yellow triangle with an exclamation mark inside) are not valid predictors of crash frequency.

This study comes on the heels of American Trucking Associations calling on FMCSA to release its own study on the links between violations and crash risk used to develop its methodology for assigning carriers' scores under CSA.

The ASECTT study, commissioned by Dr. Inam Iyoob, engineer with Transplace, shows that FMCSA's safety measurement system percentile scores account for less than 1% of the variation in crash frequency for each of these BASICs.

Iyoob says FMCSA's data 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.

But consumers of freight transportation do not select "average" carriers, Iyoob says.

"I can't see any useful purpose in averaging the crash data of hundreds of carriers in each of 100 different percentiles and then calculating a regression of the average values," Iyoob says. "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."

The study notes that logically, unsafe driving and driver fatigue do impact crashes. However, the way the SMS BASICs Unsafe Driving and Fatigued Driving are captured, calculated and interpreted by FMCSA does not show any correlation to crashes, according to this study.

You can read Iyoob's report here.

Related stories:

ATA Demands FMCSA Release Study Used to Develop CSA Scoring System

FMCSA Stops Plan to Determine Accountability in CSA Crash Data

ATA: Common Sense Must Govern CSA Crash Accountability Decisions