As the National Highway Traffic Safety Administration (NHTSA) gears up to introduce a new federal motor vehicle safety standard (FMVSS) which would mandate electronic stability control (ESC) on all new commercial tractors with a gross vehicle weight rating (GVWR) greater than 26,000 lbs., a study by the American Transportation Research Institute (ATRI) indicates the agency may be backing the wrong technology from both a safety and cost effectiveness standpoint.
The ATRI’s analysis of the two primary roll stability systems available to the trucking industry today – ESC and roll stability control (RSC) – determined, using crash data supplied directly by carriers, that RSC not only prevents more rollovers, jackknifes, and “tow/stuck” incidents, it’s far less expensive and allows trucking companies to recoup their installation costs quicker.
"Basically, we gathered enough data to show that there's too much nuance between RSC and ESC, and that RSC is plenty adequate in preventing a wide range of crashes at a lower cost," Dan Murray, ATRI's vp-research, told Fleet Owner.
ATRI noted its study sample included a total of 135,712 trucks, of which 68,647 were equipped with RSC, 39,529 trucks equipped with ESC, and 27,536 trucks equipped with no roll stability system (RSS) whatsoever. Carriers that provided data operated primarily in the TL sector (81.5%), followed by the LTL sector at 10% and specialized carriers at 8.5%.
While Murray said this sample is indeed small -- involving only 5% to 10% of the 3.2 million or so commercial trucks operating in the U.S. -- it "intuitively" represents those companies that have invested in both technologies, providing a clear opportunity to compare them against each other as well as against trucks not equipped with RSS.
The group’s research found that RSC-equipped trucks had a 60% lower rollover crash rate compared to trucks without RSS technology (4.22 rollovers per 100 million miles versus 10.62) while ESC-equipped trucks only demonstrated a 47% lower rollover crash rate compared to trucks with no RSS system (5.60 rollovers per 100 million miles versus 10.62).
For jackknife crashes, both RSC and ESC had similar crash rates of 3.49 and 3.89 jackknife crashes per 100 million miles, respectively, while RSC-equipped trucks had a 22% lower tow/stuck crash rate (23.67 per 100 million miles versus ESC trucks (30.77 per 100 million miles), ATRI determined.
In terms of what those numbers mean in terms of money, ATRI said that when rollover and jackknife costs are aggregated, RSC-equipped trucks experienced average crash costs of $4.31 per 1,000 miles, with ESC-equipped trucks generating crash costs averaging $5.27 per 1,000 miles – while trucks with no RSS technology at all incurred $12.25 per 1,000 miles on average.
The group thus concluded that trucks equipped with RSC not only experienced lower rollover crash rates than trucks equipped with ESC, RSC-equipped trucks achieved an 18.2% lower average crash costs as compared to ESC-equipped trucks.
Those two data points proved even more critical when the price tags for the two systems were subsequently compared, ATRI said. Based on motor carrier responses to the group’s survey, the average cost for an RSC system totaled $467.18, whereas an ESC system cost, on average, $1,180.88; some 152.8% higher than RSC in the sample data.
That significant price gap affected the “payback analysis” for each technology, as given the lower crash rates, lower crash costs, and lower equipment costs of RSC compared to ESC, the return on investment for RSC becomes more favorable, ATRI said – with carriers installing RSC typically recouping the installation cost after 58,842 miles per truck, versus 169,101 miles per truck for ESC.
The ATRI’s findings could be critical as they contradict NHTSA’s own study on the subject, as the agency’s research found ESC to provide better protection against crashes than RSC.
That study – entitled Safety Benefits of Stability Control Systems For Tractor-Semitrailers – was conducted by the University of Michigan Transportation Research Institute (UMTRI) under a cooperative agreement between NHTSA and Meritor WABCO.
It determined that if ESC was fitted to all tractor-trailers, savings from rollovers prevented that technology would total $1.527 billion annually, and from LOC [loss of control] crashes prevented at $210 million annually, for a total of $1.738 billion annually.
By contrast, NHTSA’s study found that savings from rollovers prevented by RSC would only total $1.409 billion annually, and from LOC crashes save $47 million annually, for a total estimated benefit of $1.456 billion per year.
Murray stressed however that NHTSA's research revolves around the "societal cost" benefits those technologies offer, not a more down-to-earth analysis that measures the cost effectiveness of RSC and ESC in terms of trucking's bottom line.
"[NHTSA] research doesn't take into account the low margins in trucking, high competition, and other cost pressures in the industry," he explained. "At the end of the day it's about cost efficiency. If you can get the exact same preventive benefit against rollovers from RSC at half the cost, with ESC only providing incremental benefit for other types of crashes such as jackknifes, it's difficult to justify mandating one over the other."
