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Safety Recommendation Details

Safety Recommendation H-11-007
Details
Synopsis: 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.
Recommendation: TO THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION: Develop stability control system performance standards for all commercial motor vehicles and buses with a gross vehicle weight rating greater than 10,000 pounds, regardless of whether the vehicles are equipped with a hydraulic or a pneumatic brake system. This recommendation supersedes Safety Recommendation H-10-5.
Original recommendation transmittal letter: PDF
Overall Status: Open - Unacceptable Response
Mode: Highway
Location: Indianapolis, IN, United States
Is Reiterated: Yes
Is Hazmat: No
Is NPRM: No
Accident #: HWY10MH001
Accident Reports:
Rollover of a Truck-Tractor and Cargo Tank Semitrailer Carrying Liquified Petroleum Gas and Subsequent Fire
Report #: HAR-11-01
Accident Date: 10/22/2009
Issue Date: 9/2/2011
Date Closed:
Addressee(s) and Addressee Status: NHTSA (Open - Unacceptable Response)
Keyword(s): Stability

Safety Recommendation History
From: NTSB
To: NHTSA
Date: 7/12/2019
Response: We previously recognized your progress toward addressing heavy vehicle stability control in your June 23, 2015, final rule; however, we noted that it was limited to truck-tractors and certain buses over 26,000 pounds GVWR. We are disappointed that you excluded other vehicles—including school buses—from the rule, and we urge you to reconsider your position and extend the mandate. A stability control system is an important component of effective automatic emergency braking and collision avoidance systems. In our school bus transportation safety report, we recommended that school bus manufacturers install stability control systems on their new vehicles as an interim measure until your rulemaking is complete, and some have informed us that they are working to accomplish this for both pneumatic- and hydraulic-braked vehicles. In the 4 years since you published the final rule, this technology has changed rapidly and is now widely available and in use. A federal mandate creates a level playing field and will keep school districts from having to choose to implement this important safety technology. Pending such action, Safety Recommendations H-11-7 and -8 remain classified OPEN--UNACCEPTABLE RESPONSE.

From: NHTSA
To: NTSB
Date: 3/4/2019
Response: -From Heidi R. King, Deputy Administrator: On June 23, 2015, NHTSA issued Federal Motor Vehicle Safety Standard (FMVSS) No. 136, Electronic Stability Control (ESC) systems for heavy vehicles. It applies to truck tractors and buses with a GVWR greater than 11, 793 kilograms (26,000 pounds), with some exceptions. NHTSA stated that including buses with hydraulic brakes in the final rule will spur the development of ESC systems for other hydraulic-braking vehicles, including trucks with a GVWR greater than 4,536 kilograms (10,000 pounds) but not more than 11,793 kilograms (26,000 pounds). School buses were excluded from the ESC final rule because the crash statistics indicate that most school bus crashes are not rollover or loss-of-control crashes that ESC systems can prevent. Despite the exclusion of these vehicle types, we note that several manufacturers do offer ESC systems as optional equipment for school buses and heavy vehicles not covered by FMVSS No. 136. For these reasons, we request that Safety Recommendations H-11-007 and H-11-008 be closed.

From: NTSB
To: NHTSA
Date: 6/21/2018
Response: From the NTSB Special Investigative Report “Selective Issues in School Bus Transportation Safety: Crashes in Baltimore, Maryland, and Chattanooga, Tennessee.” Report Number SIR-18-02. 7.1.2 Safety Recommendations In the absence of CAS and ESC requirements for school buses, some manufacturers—such as Thomas Built Buses and Blue Bird—are moving ahead on developing these technologies for their vehicles. Since 2015, they have offered ESC as an option and have installed the feature on 230 pneumatically braked vehicles. NTSB crash investigations and industry research have shown that CAS with AEB and ESC is an effective countermeasure to prevent or mitigate the severity of crashes and to reduce the frequency of rear-end or loss-of-control crashes. The Baltimore school bus driver was medically incapacitated when the school bus struck the car, entered the oncoming traffic lanes, and struck the transit bus. The NTSB concludes that had the newly manufactured Baltimore school bus been equipped with a forward CAS with AEB, the initial impact with the car would likely have been mitigated; and the subsequent impact between the school bus and the transit bus would not have occurred. In the Chattanooga crash, the driver lost control of the 2008 Thomas Built school bus in a situation in which ESC systems might have mitigated the outcome.141 NTSB investigators used simulations to evaluate the potential effects of an ESC system on a school bus traversing this roadway at the same speed as the Chattanooga bus. Results of these vehicle dynamic simulations showed that an ESC system would have activated and reduced the speed of the bus on the curve immediately preceding the crash location. The simulated ESC activation achieved speed reductions of about 10 mph (to 42 mph from 52 mph). Although it was not possible to determine if the driver could have successfully negotiated the curve at the reduced speed, the simulations showed that the associated changes in handling characteristics would have made the bus more controllable during the maneuver. Further, if a crash still resulted, the reduced speed would have decreased the severity of the crash forces. The NTSB concludes that had the vehicle instability—caused by the Chattanooga bus driver’s excessive speed and steering input—occurred in a newly manufactured school bus equipped with an ESC system, the technology could have assisted the driver in maintaining vehicle control and mitigated the severity of the crash by reducing the speed of the vehicle. Although statistics show that school buses offer the safest transportation to and from school, CAS, AEB, and ESC offer large safety benefits in helping to prevent or mitigate the severity of crashes. According to NHTSA, when it was developing the final rule for FMVSS 136, school buses were excluded from the performance standard because ESC technology was not available on the vehicles being researched and tested. Since that time, the NTSB has met with NHTSA to discuss that ESC-equipped school buses are now available and can be tested. Therefore, the NTSB reiterates Safety Recommendations H-11-7 and -8 to NHTSA. Furthermore, the NTSB also recommends that NHTSA require all new school buses to be equipped with CAS and AEB technologies.

From: NTSB
To: NHTSA
Date: 11/13/2017
Response: Although we recognize your progress toward addressing heavy vehicle stability control in your June 23, 2015, final rule, we noted that it was limited to truck-tractors and certain buses over 26,000 pounds GVWR. Please send us an update outlining your planned actions and a timeline for addressing stability control in the remaining vehicle categories included in these recommendations. Pending such information, Safety Recommendations H-11-7 and -8 are classified OPEN--UNACCEPTABLE RESPONSE.

From: NTSB
To: NHTSA
Date: 6/7/2016
Response: We are pleased that, on June 23, 2015, you published a final rule mandating stability control systems for truck tractors and certain buses with a GVWR greater than 26,000 pounds. We are encouraged by your progress, and note that you continue to collect information on other commercial vehicle types in preparation for additional rulemaking. Accordingly, we look forward to NHTSA’s issuing electronic stability control rulemaking for the remaining vehicle categories addressed in these recommendations. Pending completion of the recommended actions and our review of the resulting final rules, Safety Recommendations H-11-7 and -8 remain classified OPEN—ACCETPABLE RESPONSE.

From: NTSB
To: NHTSA
Date: 3/21/2016
Response: -From Mark R. Rosekind, Ph.D., Administrator: We request that these recommendations be classified as "Closed- Acceptable Response." On June 23, 2015, NHTSA published a final rule establishing Federal Motor Vehicle Safety Standard Number 136 to require electronic stability control (ESC) systems on truck traitors and certain buses. We believe that publication of this final rule fully addresses the safety needs identified in these two recommendations.

From: NTSB
To: NHTSA
Date: 6/8/2015
Response: The NTSB reiterated Safety Recommendation H-11-007 in its special investigative report "The Use of Forward Collision Avoidance Systems to Prevent and Mitigate Rear-End Crashes" (SIR-15-01, PB2015-104098, Notation 8638, adopted May 19, 2015). The NTSB continues to be concerned with the issue of stability control for commercial vehicles and has made seven recommendations pertaining to ESC technology since 2002 (see appendix A for recent recommendations pertaining to ESC). In its most recent recommendation (H-11-8), the NTSB asked NHTSA to require all new commercial vehicles to be equipped with such systems. In its most recent correspondence on this recommendation, dated December 2014, NHTSA responded that it was preparing a final notice to consider mandating stability control systems in truck-tractors and motorcoaches. This recommendation, as well as the accompanying recommendation to NHTSA to develop ESC performance standards for commercial vehicles (H-11-7), is currently classified “Open—Acceptable Response.” Because of the importance of ESC in the application of forward CAS with AEB, the NTSB reiterates Safety Recommendations H-11-7 and -8.

From: NTSB
To: NHTSA
Date: 3/30/2015
Response: We note that you are preparing a final rule mandating stability control systems for truck tractors and motorcoaches, and continue to collect information on other commercial vehicle types in preparation for additional rulemaking. We are encouraged by your progress. As you pointed out, electronic stability control (ESC) systems are effective for Class 7 and 8 pneumatic braked single-unit trucks, and appropriate technology is currently available; however, these large trucks were excluded from your proposed rule. Accordingly, we look forward to NHTSA’s issuing ESC rulemaking for single-unit trucks. Pending completion of the recommended actions and our review of the resulting final rules, Safety Recommendations H 11 7 and -8 are classified OPEN—ACCEPTABLE RESPONSE.

From: NHTSA
To: NTSB
Date: 12/3/2014
Response: -From David J. Friedman, Deputy Administrator: NHTSA is currently preparing the final notice to consider mandating electronic stability control systems (ESC) on truck tractors and motorcoaches. NHTSA has also performed significant research on single unit truck and bus (SUT) ESC. Our past research has shown that ESC is effective for Class 7 & 8 pneumatic-braked SUTs. Unfortunately, there is a whole segment of SUTs for which this technology does not exist- hydraulic-braked Class 4- 7 SUTs. We are tentatively planning a research program to try to address this group in fiscal year 2015. While this technology exists for Class 3 SUTs, we have only tested it on one vehicle.

From: NTSB
To: NHTSA
Date: 2/10/2014
Response: We support your ongoing testing and evaluation of electronic stability control systems for commercial vehicles and the rulemaking effort that you have initiated for heavy trucks and motorcoaches; we further encourage you to continue your work to develop objective test procedures and performance metrics for stability control systems for single-unit trucks and medium-size buses. Pending completion of the recommended performance standards and implementation of a stability control requirement for all commercial vehicles weighing over 10,000 pounds, Safety Recommendations H-11-7 and -8 remain classified OPEN—ACCEPTABLE RESPONSE.

From: NTSB
To: NHTSA
Date: 7/3/2013
Response: From the Safety Study: Crashes Involving Single-Unit Trucks that Resulted in Injuries and Death, NTSB/SS-13/01, PB13-106637, adopted June 17, 2013, published July 3, 2013: Rollovers and single-vehicle run-off road crashes are two types of crashes that can be reduced by electronic stability control (ESC) systems. Prior research by Woodrooffe et al. (2012) reported that single-unit trucks were involved in more fatal loss-of-control crashes than tractor trailers, and that annual cost savings from preventing crashes by installing ESC on all single-unit trucks would be $1.2 billion to $1.5 billion. The fatal loss-of-control crashes usually resulted from single-unit truck drivers overcorrecting after encroaching upon roadway shoulders. The NTSB has previously recommended that all large commercial vehicles have electronic stability control systems (NTSB 2011b). ESC systems use automatic computer-controlled braking of individual wheels to assist the driver in maintaining control of the vehicle in critical driving situations. The NTSB’s previous recommendation is further supported by this study, which found a large number of rollovers and single-vehicle run-off road crashes among both types of trucks. During 2005–2009, an estimated 1,003 single-unit trucks and 3,667 tractor-trailers were involved in rollovers and an estimated 8,914 single-unit trucks and 16,359 tractor-trailers were involved in single-vehicle run-off road crashes nationwide. Data from the participating states indicated an average of 630 annual involvements of single-unit trucks in both rollovers and single-vehicle run-off road crashes. The NTSB concludes that single-unit trucks are involved in at least one-third of all large truck rollovers and single-vehicle run-off-road crashes, two types of crashes that can be mitigated by electronic stability control systems. As noted in the introduction of this study, NHTSA proposed mandating electronic stability control for tractor-trailers and motorcoaches in 2012 but not for single-unit trucks. The NTSB is aware of NHTSA’s concern about there being no electronic stability control systems currently on the market for hydraulically-braked, medium-weight trucks; however, as noted in the 2012 comments submitted to NHTSA in response to the proposed rule, the NTSB continues to advocate this safety technology for single-unit trucks (2012). Additionally, single-unit trucks with air brakes were not included in the proposal, although electronic stability control systems are available for them. The NTSB therefore reiterates its prior recommendations to the NHTSA to (1) develop stability control system performance standards for all commercial motor vehicles and buses with a gross vehicle weight rating greater than 10,000 pounds, regardless of whether the vehicles are equipped with a hydraulic or a pneumatic brake system (Safety Recommendation H-11-7); and (2) once the performance standards in Safety Recommendation H-11-7 have been developed, require the installation of stability control systems on all newly manufactured commercial vehicles with a gross vehicle weight rating greater than 10,000 pounds (Safety Recommendation H-11-8).

From: NTSB
To: NHTSA
Date: 2/4/2013
Response: We are encouraged that NHTSA is moving forward with its efforts to address stability control for commercial vehicles and buses over 10,000 pounds GVWR. We understand that, because of differences in vehicle dynamics, NHTSA’s initial focus in this area is on truck tractors and motorcoaches; we are further encouraged that a notice of proposed rulemaking was published in May 2012 and a final rule is expected to be published in late 2013. NHTSA continues to evaluate the performance of stability control systems for single unit heavy vehicles, including the use of multiple test maneuvers and loading conditions to develop test procedures and a benefits assessment to support the agency’s decision by 2014 to proceed with rulemaking. Accordingly, pending the development of standards and the issuance of a requirement to install stability control systems on all newly manufactured commercial vehicles with a GVWR greater than 10,000 pounds, Safety Recommendations H-11-7 and -8 are classified OPEN—ACCEPTABLE RESPONSE.

From: NTSB
To: NHTSA
Date: 8/9/2012
Response: Notation 8429: The National Transportation Safety Board (NTSB) has reviewed the National Highway Traffic Safety Administration's (NHTSA) Notice of Proposed Rulemaking to establish Federal Motor Vehicle Safety Standard (FMVSS) No. 136, Electronic Stability Control Systems for Heavy Vehicles, as published in Volume 77 of the Federal Register on May 23, 2012. The proposed rule would require truck tractors and certain buses with a gross vehicle weight rating (GVWR) over 26,000 pounds to be equipped with an electronic stability control (ESC) system meeting specified equipment and performance criteria. The NTSB has long advocated the study and implementation of crash avoidance technologies, such as ESC, to assist drivers in maintaining control of commercial motor vehicles. As a result of our investigation of a multivehicle collision in Slinger, Wisconsin, in February 1997, the NTSB recommended that NHTSA conduct research to evaluate the benefits of adding traction control devices to antilock brake systems (H-98-9). Based on NHTSA research for the current rulemaking effort, the NTSB classified this recommendation "Closed-Acceptable Action" in January 2012. In the investigation of a seven-fatal mid-size bus rollover accident in Dolan Springs, Arizona, in January 2009, the NTSB addressed the benefits of equipping buses with a GVWR greater than 10,000 pounds with stability control systems and issued Safety Recommendations H -10-5 and -6 to NHTSA: Develop stability control .system performance standard) applicahle to newly manufactured buses with a gross vehicle weight rating above 10, 000 pounds. (H-10-5) Once the performance standards from Safety Recommendation H-10-5 have been developed, require the installation of stability control systems in all newly manufactured buses in which this technology could have a safety benefit. (H-10-6) Upon completion of another commercial vehicle rollover accident investigation-in Indianapolis, Indiana, in October 2009, involving the rollover of a cargo tank trailer carrying liquefied petroleum gas and a subsequent fire3-the NTSB closed Safety Recommendations H-10-5 and -6 and issued superseding and broader Safety Recommendations H-11-7 and -8 to NHTSA: Develop stability control system performance standards for all commercial motor vehicles and buses with a gross vehicle weight rating greater than 10, 000 pounds, regardless of whether the vehicles are equipped with a hydraulic or a pneumatic brake system. (H-11-7) Once the performance standards from Safety Recommendation H-II-7 have been developed, require the installation of stability control systems on all newly manufactured commercial vehicles with a gross vehicle weight rating greater than 10, 000 pounds. (H-11-8) In the Indianapolis investigation, the NTSB also concluded that a retrofit for stability control systems would be advantageous given the long service life of cargo tank trailers and the potential safety risks posed by the hazardous materials they typically transport. And, because roll stability control (RSC) systems do not require the same integrated sensors and communication systems as ESC, making them more feasible to install as a retrofit, the NTSB issued Safety Recommendation H-11-3 to the Federal Motor Carrier Safety Administration: Require all in-use cargo tank trailers with a gross vehicle weight rating greater than 10, 000 pounds to be retrofitted with a rollover stability control system. (H-1l-3) The proposed rule has assessed the benefits of ESC versus RSC systems, acknowledging that RSC systems lack the ability to affect the directional control of a vehicle in situations of potential rollover. The NTSB agrees with NHTSA that there are additional benefits of ESC over RSC and applauds the research and testing that NHTSA conducted to come to this conclusion. Although NHTSA found that RSC on trailers would save fewer than 10 lives per year and would not be cost beneficial, the NTSB stands by Safety Recommendation H-1l-3 for cargo tank trailers to be retrofitted with RSC systems due to the high potential they hold for catastrophic damage and loss of life in the event of a hazardous materials release. The NTSB recognizes that FMVSS No.l26 requires ESC systems to be in place on light vehicles, and the proposed rulemaking extends the requirement for ESC systems to a large number of heavy vehicles. However, between the upper bounds of FMVSS No. 126, a GVWR of 10,000 pounds, and the lower bounds of the proposed FMVSS No.136, a GVWR of 26,000 pounds, there is a gap where stability control systems will not be required. A vehicle type within this gap that is of particular interest to the NTSB is mid-size buses. The Dolan Springs bus, a mid-size bus with a GVWR of 19,500 pounds, would not be covered in the proposed ESC rulemaking. During its Dolan Springs investigation, the NTSB estimated that the production volume of mid-size buses was 11,600 units per year, on average. Mid-size buses, which are used to transport groups of 16-40 people, should be held to the same--if not higher standards than vehicles used to transport cargo. Mid-size buses also have higher centers of gravity than many other passenger-carrying vehicles, making them more prone to rollover, and therefore more likely to benefit from rollover prevention technologies. The proposed rule also does not address ESC systems for other types of buses, and instead proposes exemptions for buses with fewer than 16 seating positions, buses with limited forward-facing seating configurations (such as limo-buses), urban transit buses, and school buses. We understand that certain exemptions to the rule may be required for slow-moving or specialty vehicles, but when it comes to vehicles that transport people, especially children, the NTSB encourages NHTSA to be as far-reaching as possible when implementing life-saving safety technologies such as ESC. The proposed rule also excludes medium-duty and single-unit trucks, which could benefit from stability control systems. As pointed out in the proposed rulemaking, a safety benefit study applicable to such commercial vehicles is underway, and ESC systems are still in development for medium-duty trucks and buses equipped with hydraulic brakes. The NTSB is pleased to see that steps are underway to equip the largest populations within the commercial vehicle fleet with stability control systems without waiting for their availability on all types of vehicles, but we will continue to advocate that this safety technology be universal. As recognized in the proposed rule, the NTSB has also issued safety recommendations on collision warning with active braking and adaptive cruise control systems, for which ESC systems are required as a baseline technology to enable vehicle braking without driver input. In 2001, the NTSB published a Special Investigation Report of nine rear-end accidents in which 20 people died and 181 were injured,5 and issued Safety Recommendations H-01-6 and -7 to NHTSA: Complete rule making on adaptive cruise control and collision warning system performance standards for new commercial vehicles. At a minimum, these standards should address obstacle detection distance, timing of alerts, and human factors guidelines, such as the mode and type of warning. (H-01-6) After promulgating performance standards for collision warning systems for commercial vehicles, require that all new commercial vehicles be equipped with a collision warning system. (H-Ol-7) At the conclusion of the investigation of an October 2005 accident near Osseo, Wisconsin-involving the rollover of a truck-tractor semitrailer combination unit, which was subsequently struck by a motorcoach-in which 5 people died and 36 were injured,6 the NTSB reiterated Safety Recommendations H-0l-6 and -7 and issued Safety Recommendation H-08-15 to NHTSA: Determine whether equipping commercial vehicles with collision warning systems with active braking and electronic stability control systems will reduce commercial vehicle accidents. If these technologies are determined to be effective in reducing accidents, require their use on commercial vehicles. (H-08-15) We believe that the advancement of crash avoidance and mitigation technologies is dependent on equipping the entire commercial vehicle population with ESC. The NTSB understands that ESC alone cannot prevent all accidents and that conditions such as aggressive steering inputs, excessive speed, and shifting loads limit its effectiveness. For this reason, we encourage NHSTA to not only continue moving forward on accident prevention technologies, but also to develop rollover performance standards to ensure that the static rollover stability of commercial vehicles is considered and optimized in the design and manufacturing stages. The NTSB appreciates the opportunity to comment on this notice. Although we are encouraged by the proposed rulemaking and its effect on a large population of commercial motor vehicles, our open safety recommendations to NHTSA with regard to stability control systems include all commercial motor vehicles and buses with a GVWR greater than 10,000 pounds. Well-designed technology can improve driver performance and overall highway safety, and we will continue to support the development and requirement of such systems until a universal level of safety is realized.

From: NHTSA
To: NTSB
Date: 7/19/2012
Response: -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.

From: NTSB
To: NHTSA
Date: 4/30/2012
Response: This correspondence control was closed administratively. No letter was ever sent using CC# 201200223. See CC# 201200359.

From: NHTSA
To: NTSB
Date: 2/2/2012
Response: -From David L. Strickland, Administrator: Background 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. Safety Recommendations H -11-7 and H -11-8 direct NHTSA to develop stability control system performance standards for newly manufactured commercial motor vehicles and buses with a gross vehicle weight rating (GVWR) above 10,000 lb, and to then require the installation of such systems in all newly manufactured commercial motor vehicles and buses, regardless of whether they are equipped with a hydraulic or a pneumatic brake system. With regard to stability control technology, NHTSA's research and rulemaking activities for truck-tractors and motorcoaches have proceeded along a separate (and more advanced) timeline than for medium and heavy single unit trucks and other buses. This is necessary and appropriate given the substantial differences in the availability and technological progress in stability control systems within these industry segments. Therefore, in responding to recommendation H-11-7 and H-11-8, we have presented our activities for truck-tractors and motorcoaches separately from single unit trucks and other buses. Truck-tractors and Motorcoaches NHTSA has completed substantial research on electronic stability control (ESC) and roll stability control (RSC) systems for truck-tractors and for motorcoaches with GVWR over 26,000 lb. This work included evaluating the capability of ESC and RSC for mitigating loss of control and/or rollover events under a variety of vehicles, test maneuvers, loading conditions and trailer types, including a typical tank trailer. When testing with ESC, our data indicates that the technology was effective in reducing rollover crashes even when representative sloshing and surging was present. This work has been summarized in two separate reports that we are enclosing for your convenience. NHTSA has also completed a safety benefits assessment of ESC and RSC based on an analysis of historical crash data and used modeling, simulation and expert engineering judgment to determine the effectiveness of these technologies. This body of work (development of objective tests, safety benefits estimates and cost analyses) has culminated in the agency deciding to proceed with rulemaking and the development of a notice of proposed rulemaking that the agency expects to publish in the Federal Register in early 2012. Single Unit Heavy Vehicles NHTSA is evaluating the performance of available stability control systems on single unit trucks and other buses with a GVWR over 10,000 lb, relative to reducing roll and loss-of-control type crashes. Given the variety of vehicle types represented by this vehicle class, our work must not only include the evaluation of multiple test maneuvers and loading conditions but must also consider bulk liquid tank trucks among other vehicles. Our current efforts include the development of test procedures and a benefits assessment in support of an agency decision on whether to proceed forward with rulemaking. We anticipate making an agency decision on stability control for single unit vehicles (including single unit tank trucks) by 2014.