You may be trying to access this site from a secured browser on the server. Please enable scripts and reload this page.
Turn on more accessible mode
Turn off more accessible mode
Skip Ribbon Commands
Skip to main content
Top Link Bar
NEWS & EVENTS
Speeches & Testimony
Most Wanted List
The Investigative Process
Data & Stats
General Aviation Safety
Administrative Law Judges
Strategic Plans & Reports
Safety Recommendation Details
The Investigative Process
Data & Stats
General Aviation Safety
On October 22, 2009, about 10:38 a.m. eastern daylight time, a 2006 Navistar International truck-tractor in combination with a 1994 Mississippi Tank Company MC331 specification cargo tank semitrailer (the combination unit), operated by AmeriGas Propane, L.P., and laden with 9,001 gallons of liquefied petroleum gas, rolled over on a connection ramp after exiting Interstate 69 (I-69) southbound to proceed south on Interstate 465 (I-465), about 10 miles northeast of downtown Indianapolis, Indiana. The truck driver was negotiating a left curve in the right lane on the connection ramp, which consisted of two southbound lanes, when the combination unit began to encroach upon the left lane, occupied by a 2007 Volvo S40 passenger car. The truck driver responded to the Volvo’s presence in the left lane by oversteering clockwise, causing the combination unit to veer to the right and travel onto the paved right shoulder. Moments later, the truck driver steered counterclockwise to redirect and return the combination unit from the right shoulder to the right lane. The truck driver’s excessive, rapid, evasive steering maneuver triggered a sequence of events that caused the cargo tank semitrailer to roll over, decouple from the truck-tractor, penetrate a steel W-beam guardrail, and collide with a bridge footing and concrete pier column supporting the southbound I-465 overpass. The collision entirely displaced the outside bridge pier column from its footing and resulted in a breach at the front of the cargo tank that allowed the liquefied petroleum gas to escape, form a vapor cloud, and ignite. The truck-tractor came to rest on its right side south of the I-465 overpasses, and the decoupled cargo tank semitrailer came to rest on its left side, near the bridge footing supporting the southbound I-465 overpass. The truck driver and the Volvo driver sustained serious injuries in the accident and postaccident fire, and three occupants of passenger vehicles traveling on I-465 received minor injuries from the postaccident fire. The National Transportation Safety Board (NTSB) determined that the probable cause of this accident was the excessive, rapid, evasive steering maneuver that the truck driver executed after the combination unit began to encroach upon the occupied left lane. Contributing to the rollover was the driver’s quickly steering the combination unit from the right shoulder to the right lane, the reduced cross slope of the paved right shoulder, and the susceptibility of the combination unit to rollover because of its high center of gravity. Mitigating the severity of the accident was the bridge design, including the elements of continuity and redundancy, which prevented the structure from collapsing. A basic requirement for evaluating the accident performance of U.S. Department of Transportation (DOT) specification cargo tanks (such as the MC331 involved in this accident) is access to data that can be used to quantify both the involvement of those tanks in reportable incidents and the in-service population of those same tanks. While the approximate number of DOT specification cargo tanks involved in accidents may be obtained from the Hazardous Materials Information System or other databases, there is limited access to accurate information on the population of cargo tanks by DOT specification. For example, the most precise number of petroleum-hauling DOT 406 cargo tank semitrailers cited in the Cargo Tank Roll Stability Study2 appeared to be somewhere between 10,648–60,003 units. When asked at the August 2010 NTSB public hearing, a Pipeline and Hazardous Materials Safety Administration (PHMSA) official acknowledged that the agency did not know the total number of cargo tanks by DOT specification that were currently in service.3 Further, PHMSA indicated that data analyses for evaluating the performance of DOT specification cargo tanks could be enhanced if the population of cargo tanks by DOT specification were available. The NTSB concludes that the absence of a requirement for motor carriers to periodically provide the number of cargo tanks by DOT specification limits the ability to perform accurate trend analyses. The limited information currently available for PHMSA to quantify the distribution of cargo tanks by DOT specification differs considerably, for example, from information that can be accessed by the Association of American Railroads (AAR) about tank cars used for transporting bulk liquids by rail. The AAR has used the Universal Machine Language Equipment Register (UMLER) equipment management information system as the industry’s central repository for registered railroad and intermodal equipment since 1968. The UMLER system is updated in real time and capable of tracking equipment status, ownership, and inspection history and providing the particular fleet profile.
TO THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION: Establish comprehensive minimum rollover performance standards, based on the least stable condition operated, for all newly manufactured cargo tank motor vehicles with a gross vehicle weight rating greater than 10,000 pounds.
Original recommendation transmittal letter:
Open - Unacceptable Response
Indianapolis, IN, United States
Rollover of a Truck-Tractor and Cargo Tank Semitrailer Carrying Liquified Petroleum Gas and Subsequent Fire
Addressee(s) and Addressee Status:
NHTSA (Open - Unacceptable Response)
Safety Recommendation History
We are disappointed that we have not received an update from you regarding your cargo tank research or any substantive actions you have planned to address these recommendations. Failure to address this important safety issue places drivers on our nation’s roadways at risk. Please send us an update outlining your planned actions and a timeline for addressing this recommendation. Pending such information, Safety Recommendations H-11-9 through -12 are classified OPEN--UNACCEPTABLE RESPONSE.
We note that, in addition to NHTSA’s evaluation of stability control systems, the agency is planning to conduct further research on the factors contributing to the rollover of cargo tank motor vehicles. We encourage NHTSA to move forward with its evaluation of these vehicles to collect data that will permit the agency to develop and require performance standards that will better protect cargo tank motor vehicles from rollovers and will mitigate the sloshing and surging of bulk liquids in the tanks. Accordingly, Safety Recommendations H-11-9 through -12 are classified OPEN—ACCEPTABLE RESPONSE. We look forward to receiving periodic updates on the progress of your rollover research.
-Email from Melanie O’Donnell, Office of Governmental Affairs, Policy and Strategic Planning, NHTSA (July 20, 2012): Please find NHTSA’s letter updating NTSB on Recommendations H-11-07 through -12 attached. This letter details the meeting between NHTSA and NTSB on June 18 to discuss our activities in relation to these recommendations. As a reminder, we sent a letter on February 2, 2012 requesting “Open-Acceptable Response” for these recommendations. -From David L. Strickland, Administrator (July 19, 2012): I am following up with you as discussed in our letter dated February 2, 2012, in which we requested a meeting with your staff to discuss Safety Recommendations H-II-7 through H-11-12 regarding stability control systems on vehicles greater than 10,000 pounds, cargo tank motor vehicle rollover performance standards and the mitigation of sloshing and surging in cargo tank motor vehicles. A meeting was held at the National Transportation Safety Board (NTSB) on June 18, 2012, attended by staff members of NTSB and the National Highway Traffic Safety Administration (NHTSA), to discuss these subjects. NHTSA discussed ongoing activities that are related to these safety recommendations, including: • The agency's current rulemaking proposal to require electronic stability control (ESC) systems on truck tractors and large buses; • A review of the vehicle test track results for steady-state curve and transient steering maneuvers using a 9,200 gallon tanker semitrailer in combination with three different tractors; • Current test track vehicle handling and stability research on single unit trucks; and • Plans for additional test track research on single unit trucks, including a water tanker truck. We also discussed the crash problem with cargo tank motor vehicles, as those data were used in a previously-published report cited by NTSB in the September 2, 20 II, letter to NHTSA. It became evident during the meeting that more current data analysis is necessary to determine the problem size, characterize crash scenarios and identify potential countermeasures that could mitigate crashes involving cargo tank motor vehicles. We expect to begin this work in 2013. The meeting provided a good opportunity for both parties to have a free exchange of ideas, and we appreciate your cooperation in helping us to address the safety recommendations.
This correspondence control was closed administratively. No letter was ever sent using CC# 201200223. See CC# 201200359.
-From David L. Strickland, Administrator: In July 2011, the NTSB published a report titled, "Rollover of a Truck-Tractor and Cargo Tank Semitrailer Carrying Liquefied Petroleum Gas and Subsequent Fire, Indianapolis, Indiana, October 22, 2009," (Report number NTSB/HAR-1101/01 PB2011-916201), which detailed the results of an accident investigation it had conducted. This crash occurred on a connecting ramp between two interstate highways, when the driver of a truck-tractor in combination with a cargo tank semitrailer made an evasive steering maneuver after the combination unit began to encroach in the adjacent lane that was occupied by a passenger car. The truck driver's evasive steering maneuver triggered a sequence of events that caused the cargo tank semitrailer to roll over, decouple from the truck-tractor, penetrate a steel W-beam guardrail, and collide with a bridge footing and concrete pier column supporting the interstate overpass. In its report, NTSB concluded that, among other things: • A stability control system on the combination unit may have prevented the accident. • Since the cargo tank was filled to approximately 78 percent of its volume, this may have contributed to the rollover of the combination unit after the rapid, evasive maneuver was executed, due to the sloshing and surging of the partial liquid load. With regard to recommendations H-11-9 through H-11-12, NHTSA respectfully requests a meeting with members of your staff, at their earliest convenience, to discuss our research in this area and to gain a better understanding of the underlying assumptions made by the NTSB in developing these specific recommendations. NHTSA appreciates this opportunity to update NTSB on the efforts toward implementing the safety recommendations relating to heavy vehicle stability control. Given the above updates, NHTSA respectfully suggests that Recommendations H-11-7 through H-11-12 be classified as "Open Acceptable Response."
Strategic Plan, Performance & Accountability Reports & More
Directions to Conference Center
Web Policies & Notices
Annual Review of Aircraft