Too often we pick up the newspaper or go online for news and see an item about a large cargo truck turning over and causing a hazardous chemical spill. Most times, an accident of this nature either injures or kills the truck’s driver and sometimes the drivers or passengers of other vehicles on the road.

If drivers are spared from death or serious injury, there is often environmental damage, because these trucks may be transporting hazardous chemicals.

In 2008, the U.S. Dept. of Transportation (DOT) calculated there were over 1,300- cargo tank rollovers reported each year. Thirty-one percent of all fatal commercial truck rollovers involve cargo tanks. Most people mistakenly believe rollover accidents occur solely on exit ramps or on wet roads. Not true; in fact, 93 percent occur on dry roads and 56 percent happen on straight roads, not curved roads as thought, according to the DOT.

Rollover related accidents are such a huge issue that the National Transportation Safety Board (NTSB) held hearings on the benefits of requiring stability control technology. The hearings took place over two days in August 2010, prompted by an October 22, 2009 incident in Indianapolis involving a truck tractor and cargo tank semitrailer carrying liquefied petroleum gas. This particular accident not only caused serious injury to two drivers, but subsequent fires as well.

Following this accident and several others mentioned during the hearing, the NTSB issued recommendations that included addressing driver training, highway design and vehicle stability.

In her opening statement at the public hearing on August 3, 2010, Debbie Hersman, chairman of the National Transportation Safety Board, said the purpose of this hearing is to examine the factors that can lead to tank truck rollovers and determine what actions we can take to mitigate these factors. Specifically they would be looking into the capability and limitations of electronic stability control systems and other factors.

“The National Transportation Safety Board has been concerned about the rollover integrity of cargo tanks associated with the subsequent release of high-risk hazardous materials for more than 40 years,” said Hersman.

Director of Crash Avoidance Standards at the National Highway Traffic Safety Administration (NHTSA), Nathaniel Beuse, testified that Electronic Stability Control (ESC) and Roll Stability Control (RSC) could prevent nearly 3,500 rollover accidents and save an estimated 106 lives a year if they were required on cargo trucks.

The stability control could also prevent about 4,400 injuries annually. These numbers are based on a study of the stability systems the agency conducted with researchers from the University of Michigan Transportation Research Institute (UMTRI).

The study, Safety Benefits of Stability Control Systems for the Tractor-Semitrailers, was done under an agreement with NHTSA and Meritor WABCO. Its data was based on the analysis of independent crash datasheets using engineering and statistical techniques. They used this data to estimate the plausible benefits of stability control technologies.

Stability control technologies include sensors that monitor vehicle dynamics and estimate the stability of a vehicle, based on its mass. Stability control technology comes in two forms: Electronic Stability Control (ESC), which helps improve the safety of a vehicle by detecting and minimizing skids, and Roll Stability Control (RSC) systems, which automatically reduce the throttle and apply engine and foundation brakes to counteract the tendency of a vehicle to roll over because of excessive speed in a curve.

RSC systems address roll instability, while ESC systems address both roll and yaw instability (loss of vehicle directional control). Crashes caused by excessive speed in curves and loss of vehicle control are typical instability situations that are addressed by both RSC and ESC technologies.

Since the use of stability control technology on cargo trucks is still in a relatively new phase, there is not sufficient comprehensive crash data. However, using the approach of looking at scenarios from crash databases that could have benefited from stability control technology estimated the likely effectiveness. This comprehensive report could most likely lead to a mandate, where cargo trucks will have to be retrofitted with stability control technology. The European Commission has confirmed a proposal for the mandatory introduction of ESC on all new cars and commercial vehicle models sold in the EU from 2012.

Although saving lives is important and the first priority, the retrofitting of stability control technology could save billions in economic loss, according to the report.

Assuming ESC was fitted to all tractor semitrailers; savings from rollovers prevented by ESC are estimated at $1.527 billion annually, and from LOC crashes prevented at $210 million annually, for a total of $1.738 billion annually. Assuming RSC was fitted to all tractor-semitrailers, savings from rollovers prevented at estimated at $1.409 billion annually, and from LOC crashes prevented at $47 million annually, for a total estimated benefit of $1.456 billion annually.**

According to the U.S. Dept. of Transportation, the price of these particular stability control systems varies depending on the particular system’s capability. The prices can range from less than $500 to over $1000. Some manufactures’ are including ESC/RSC systems as standard on new vehicles. The estimated cost to retrofit older vehicles is $1200, reportedly. FSM * To read the full UMTRI report, Safety Benefits of Stability Control Systems for Tractor-Semitrailers

http:// deepblue.lib.umich.edu/bitstream/ 2027.42/64283/1/102397.pdf.

*To review a copy of Analysis of Benefits and Costs of Roll Stability Control Systems for the Trucking Industry visit: www.fmcsa.dot.gov/facts-research/researchtechnology/ report/09-020-rp-roll-stability.pdf.

*National Transportation Safety Board Public Hearing, www.ntsb.gov/events/2010/ indianapolis-in/opening-statement.htm