Skip Ribbon Commands
Skip to main content
Safety Recommendation Details

Safety Recommendation H-13-015
Details
Synopsis: There are 8.22 million single-unit trucks1 registered in the United States, which travel more than 110.7 billion miles each year. Although single-unit trucks comprise three percent of registered motor vehicles and four percent of miles traveled, they are involved in nine percent of fatalities among passenger vehicle occupants in multivehicle crashes. Crashes involving single-unit trucks and passenger vehicles pose a hazard to passenger vehicle occupants due to differences in weight, bumper height, and vehicle stiffness.2 The National Transportation Safety Board (NTSB) undertook this study because of concerns about the safety record of single-unit trucks and an interest in identifying countermeasures to address the risks posed by these vehicles. Single-unit trucks are excluded from some safety rules applicable to tractor-trailers. Single-unit trucks do not have to meet the requirements for improved rear underride guards (mandatory in 1998 for new trailers) and conspicuity treatments to enhance visibility (mandatory in 1993 for new trailers; in 1997 for new truck-tractors; and in 2001 for trailers manufactured before 1993). Further, in 2012, the National Highway Traffic Safety Administration (NHTSA) proposed mandating electronic stability control for tractor-trailers and motorcoaches but not for single-unit trucks. Many studies of truck safety have examined fatalities as the sole outcome of interest. Tractor-trailers result in a larger proportion of fatal injuries from large truck crashes, which is one reason why some truck safety regulations have been limited to tractor-trailers and trailers. However, this study shows that there are substantial societal impacts resulting from non-fatal injuries arising from single-unit truck crashes. Emergency department visits, inpatient hospitalizations,3 and hospital costs4 that result from the crashes provide measures of the adverse effect of non-fatal injuries on the public. This study also shows that federal and state databases frequently misclassify single-unit trucks and thus undercount the total number of fatalities resulting from single-unit truck crashes by approximately 20 percent. The primary focus of this study was on the risks of single-unit truck crashes, and these risks were compared with those of tractor-trailer crashes. This study used a variety of data sources. Crash Outcome Data Evaluation System (CODES) data, which links hospital discharge records with police accident reports, were obtained from five participating states (Delaware, Maryland, Minnesota, Nebraska, and Utah) and served as the primary source of data for injury severity and hospitalizations in relation to truck and accident characteristics. Additional databases used include Trucks in Fatal Accidents (TIFA) and the Fatality Analysis Reporting System (FARS) (fatal crashes); the National Automotive Sampling System (NASS)/General Estimates System (GES) (national estimates of non-fatal injuries); and the Large Truck Crash Causation Study (LTCCS) (truck crash investigations with details not available from the other sources). To improve the quality and accuracy of CODES data, the NTSB developed and used a program to decode truck vehicle identification numbers (VIN); this program was used in conjunction with VIN-derived gross vehicle weight ratings (GVWR) supplied by NHTSA. Additionally, the CODES staff used statistical procedures to impute missing values for critical variables in the data sent to the NTSB and thereby maximize the data available for analysis. This approach avoids the bias introduced by omitting records with missing values. This comprehensive approach resulted in a detailed characterization of single-unit truck crash types and the associated fatalities and injuries.
Recommendation: TO THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION: Develop performance standards for rear underride protection systems for single-unit trucks with gross vehicle weight ratings over 10,000 pounds.
Original recommendation transmittal letter: PDF
Overall Status: Open - Unacceptable Response
Mode: Highway
Location: Washington, DC, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: HVYTRUCKSTUDY
Accident Reports:
Report #: SS-13-01
Accident Date: 5/17/2011
Issue Date: 7/3/2013
Date Closed:
Addressee(s) and Addressee Status: NHTSA (Open - Unacceptable Response)
Keyword(s):

Safety Recommendation History
From: NHTSA
To: NTSB
Date: 11/8/2019
Response: -From James C. Owens, Acting Administrator: NHTSA requests that safety recommendations H-13-15 and H-13-16 be classified as "Closed Acceptable Action" for the following reasons: On July 23, 2015, NHTSA published an Advance Notice of Proposed Rulemaking (ANPRM) requesting comment on NHTSA's estimate of the costs and benefits of requirements for rear impact guards on single-unit trucks (SUTs). NHTSA's cost-benefit analysis concluded that a requirement to equip SUTs with rear impact guards would not be cost effective. NHTSA is working to withdraw this ANPRM. (https://www.reginfo.gov/public/do/eAgenda ViewRule?publd=20181O&RIN=2l27-AL57).

From: NTSB
To: NHTSA
Date: 11/13/2017
Response: We are disappointed that your December 2015 NPRM, “Rear Impact Guards, Rear Impact Protection,” excluded both rear underride protection systems and side and rear conspicuity treatments for single-unit trucks. We urge you to move forward with rulemaking to address these important safety issues for this overlooked class of vehicles. Pending such rulemaking, Safety Recommendations H-13-15 through -17 are classified OPEN--UNACCEPTABLE RESPONSE.

From: NTSB
To: NHTSA
Date: 2/3/2016
Response: The National Transportation Safety Board (NTSB) has reviewed the National Highway Traffic Safety Administration’s (NHTSA) notice of proposed rulemaking (NPRM) titled “Rear Impact Guards, Rear Impact Protection,” which was published at 80 Federal Register (78418) on December 16, 2015. The NPRM requests comments on NHTSA’s proposal to upgrade Federal Motor Vehicle Safety Standard (FMVSS) No. 223, “Rear impact guards,” and FMVSS No. 224, “Rear impact protection.” Specifically, NHTSA proposes adopting (1) the Canada Motor Vehicle Safety Standard (CMVSS) test and performance requirements for rear impact guards, CMVSS No. 223, “Rear impact guards,” and (2) Transport Canada’s definition of “rear extremity,” which specifies where aerodynamic fairings should be placed on a trailer to avoid posing a safety hazard in rear underride crashes. The NTSB supports these proposed rule changes; however, the NTSB is concerned about the continued exclusion of some large truck trailers and single-unit trucks (SUT) from FMVSS No. 224. Additionally, the exclusion of SUTs from FMVSS No. 224 has been a consistent NTSB concern. In its 2013 safety study, Crashes Involving Single-Unit Trucks that Resulted in Injuries and Deaths, the NTSB found that the adverse effects of SUT crashes have been underestimated in the past because these trucks are frequently misclassified and thus undercounted in federal and state databases (about 20 percent in the case of fatalities). There are substantial societal impacts resulting from SUT crashes, including deaths, non-fatal injuries, hospitalizations, and hospital costs. As a result of this 2013 safety study, the NTSB issued the following recommendations to NHTSA: Develop performance standards for rear underride protection systems for single unit trucks with gross vehicle weight ratings over 10,000 pounds. (H 13 15) Once the performance standards requested in H-13-15 have been developed, require newly manufactured single-unit trucks with gross vehicle weight ratings over 10,000 pounds to be equipped with rear underride protection systems meeting the performance standards. (H-13-16) On July 23, 2015, NHTSA published an advanced notice of proposed rulemaking (ANPRM) requesting comments on NHTSA’s estimated costs and benefits of underride guards as well as conspicuity treatments on SUTs. On September 21, 2015, the NTSB stated in its comments in response to the ANPRM: The NTSB supports the NHTSA proposal to examine strategies that both increase crash protection and increase the likelihood of avoiding a crash into SUTs. Further, the NTSB supports an upgraded performance requirement for rear impact guards that would improve safety for light vehicle occupants in the event of a rear end impact crash into either a trailer or an SUT. Lastly, the NTSB supports NHTSA’s proposal to revise FMVSS No. 224 to adopt Transport Canada’s definition of rear extremity, which specifies where aerodynamic fairings should be placed on a trailer so that they do not compromise the safety of occupants in a striking vehicle during a collision. The NTSB appreciates the opportunity to comment on this notice.

From: NTSB
To: NHTSA
Date: 9/21/2015
Response: The National Transportation Safety Board (NTSB) has reviewed the National Highway Traffic Safety Administration’s (NHTSA) advance notice of proposed rulemaking (ANPRM), “Rear Impact Protection, Lamps, Reflective Devices, and Associated Equipment, Single Unit Trucks,” which was published at 80 Federal Register (FR) 43663, July 23, 2015. The ANPRM invites public comment on the estimated costs and benefits of requirements for underride guards on single unit trucks (SUTs) and for retroreflective material on the rear and sides to improve the conspicuity of an SUT to other motorists. NHTSA will use the information gathered from this action to assess the benefits, costs, and other impacts of strategies, including rulemaking to upgrade Federal Motor Vehicle Safety Standard (FMVSS) No. 223, “Rear impact guards,” and FMVSS No. 224, “Rear impact protection,” which increase crash protection to the occupants of vehicles crashing into the rear of SUTs or increase the likelihood of avoiding a crash into SUTs. Additionally, NHTSA plans to issue a separate notice of proposed rulemaking to upgrade the requirements for all rear impact guards (both SUTs and trailers). The NTSB supports the NHTSA proposal to examine strategies that both increase crash protection and increase the likelihood of avoiding a crash into SUTs. Further, the NTSB supports an upgraded performance requirement for rear impact guards that would improve safety for light vehicle occupants in the event of a rear end impact crash into either a trailer or an SUT. Rear Underride Protection and Conspicuity NHTSA published this ANPRM following a July 2014 grant of a petition for rulemaking from Marianne Karth and the Truck Safety Coalition and in response to the NTSB safety recommendations issued in the 2013 Safety Study, Crashes Involving Single-Unit Trucks That Resulted in Injuries and Deaths. The NTSB study found that crashes involving SUTs and passenger vehicles pose a hazard to passenger vehicle occupants due to differences in weight, bumper height, and vehicle stiffness. In response to study findings, we recommended that newly manufactured SUTs with a GVWR over 10,000 pounds have rear underride protection systems (Safety Recommendations H-13-15 and -16). In addition, we recommended the installation of conspicuity treatments on the sides and rears of newly manufactured SUTs (Safety Recommendation H-13-17) and the retrofit of existing SUTs with conspicuity treatments (Safety Recommendation H-13-25). As noted in our safety recommendation letter to NHTSA, the installation and use of rear impact guards and conspicuity materials on SUTs would make these trucks more visible to other motorists and reduce the potential for vehicle underride and passenger compartment intrusion crashes due to occupant contact with the rear end structure, resulting in fatalities and injuries to the occupants of light passenger vehicles.

From: NTSB
To: NHTSA
Date: 3/30/2015
Response: We note that you analyzed rear underride truck crash data and, on July 10, 2014, published a grant of petition notice indicating your intent to publish an advance notice of proposed rulemaking (ANPRM) regarding rear impact guards and other safety strategies for single-unit trucks. We are encouraged by the progress you have made toward addressing these recommendations. Accordingly, pending completion of the recommended actions and our review of the final rule, Safety Recommendations H-13-15 and -16 are classified OPEN—ACCEPTABLE RESPONSE.

From: NHTSA
To: NTSB
Date: 12/3/2014
Response: -From David J. Friedman, Deputy Administrator: Last year, the agency completed a two-year research program to collect and analyze crash data on rear underrides in fatal truck crashes. The data on rear-end geometry of single unit trucks, impact characteristics, underride extent, and impact speed was collected as a supplement to the Trucks Involved in Fatal Accidents (TIF A) survey. NHTSA also analyzed technical reports and crash test data from the Insurance Institute for Highway Safety and Transport Canada. On July 10, 2014, we published a grant notice signifying our intent to publish an advanced notice of proposed rulemaking (ANPRM) pertaining to rear impact guards for single unit trucks and other safety strategies not currently applicable to single unit trucks. See 79 FR 39362. As part of its rulemaking effort, NHTSA will take into account currently available data and seek additional information from the public specific to single unit trucks. We plan to publish the ANPRM in 2015.

From: NTSB
To: NHTSA
Date: 5/24/2014
Response: According to Title 49 United States Code Section 1135, “the Secretary [of Transportation] shall give to the [NTSB] a formal written response to each recommendation not later than 90 days after receiving the recommendation.” Nearly a year has passed since we issued Safety Recommendations H-13-11 through -18, and we have not yet received your response regarding actions to address them. Accordingly, Safety Recommendations H-13-11 through -18, which have been classified “Open?Await Response” since their issuance, are now classified OPEN—UNACCEPTABLE RESPONSE.