NTSB Issues Rollover Recommendations Aimed at Improving Tank Truck Safety

The National Transportation Safety Board last week issued a slate of comprehensive regulatory recommendations aimed at reducing the number of cargo tank truck rollovers by mandating the installation of roll stability technologies and improved cargo tank design.

Although NTSB Chairman Deborah Hersman said cargo tank rollovers have been a concern for the past 40 years, the board’s sweeping recommendations to four federal regulatory agencies were the first-ever on the issue of tank truck rollovers.

“Every year, in the United States there are more than 1,300 cargo-tank truck rollovers,” Hersman said at a July 26 hearing. “Tankers represent about 6% of the commercial motor vehicle fleet. However, the rollover rate of cargo tank trucks is more than double that of non-tank trucks and accounts for about one-half of truck driver deaths and nearly one-half of incapacitating injuries.”

The recommendations were made after a three-hour hearing during which the board examined a serious liquid propane tank truck rollover in 2009 near Indianapolis. The board concluded the rollover was probably caused by the driver’s “excessive rapid steering maneuver” to return the combination unit from the right shoulder to the right lane after avoiding a passenger vehicle in an adjacent left lane on an interstate connection ramp.

The accident and subsequent vapor cloud and fire seriously injured the driver and injured three other motorists.

Hersman said the NTSB took a “holistic approach” in investigating the causes of tank truck rollovers.

“We looked at the driver, at the vehicle and at the environment, and we made recommendations to address all three areas,” Hersman told Transport Topics. “We believed that these recommendations really go a long way towards making tanker fleets safer.”

Hersman said that some of the board’s recommendations already have been mandated in Canada and some European countries.

The recommendations included a request that the Federal Motor Carrier Safety Administration require all in-use cargo tank trailers weighing more than 10,000 pounds to be retrofitted with roll stability control systems. Another was that the agency work with the Pipeline and Hazardous Materials Safety Administration to develop and disseminate guidance to assist hazardous materials carriers in implementing comprehensive cargo tank motor vehicle rollover prevention programs.

The NTSB also recommended that FMCSA revise its MCS-150 form to require that both interstate and intrastate hazmat carriers report the number and types of cargo tanks they own or lease. At present, federal regulators do not know the number of cargo tanks in operation, NTSB said.

The NTSB also recommended that PHMSA conduct a comprehensive analysis of all available cargo tank accident data to identify design problems, and develop performance standards to eliminate or mitigate the risks.

At last week’s rollover hearing, NTSB staff members told the board that the most effective ways to improve design are to build cargo tanks with a lower center of gravity and a wider wheel base.

Once PHMSA develops the performance standards, it should require that all newly manufactured cargo tanks comply with the performance standards, NTSB said.

NTSB also recommended that National Highway Traffic Safety Administration develop rollover stability system mandates and evaluate the effect of emergency maneuvers on the sloshing and surging of bulk liquids in cargo tanks.

NHTSA has been working on a proposed rollover stability system mandate, but has yet to issue a proposal, said John Conley, president of National Tank Truck Carriers.

Conley said he welcomed further study of many of the issues raised by NTSB, but noted that NTTC since 2008 has supported a rollover stability systems mandate on new tank tractors.

“I agree that we need what the chairman called a holistic approach,” Conley told TT. “I think they did a very thorough and good report. But there will be parts of it that will give us some heartburn.”

Most rollovers are the result of human error, he said.

“These are mostly single-vehicle accidents where root cause analysis does not have to go much deeper than ‘speed too fast for conditions’ or ‘overcorrected and overturned’ or ‘distracted,’ ” Conley said.

Sean McNally, spokesman for American Trucking Associations, said ATA has “long believed in active safety technologies like electronic stability control and would encourage the government to look at incentives to encourage wider industry adoption of these devices.”

A spokeswoman for FMCSA said the agency is reviewing the NTSB recommendation. An NHTSA spokeswoman did not comment by presstime.

Other NTSB recommendations included a suggestion that the Federal Highway Administration provide information to state transportation agencies about the safety risks associated with cross-slope breaks and their potential for increasing the rollover propensity of commercial vehicles with a high center of gravity.