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7 Safety of Heavy Vehicles High-Level Technical Targets and Timetables truck safety support the 21CTPâs vision of truck safety. Therefore, as a compromise, the committee elected to use Introduction the DOT safety goals, and to review selected DOT projects that support them. Moreover, this review of DOT programs The vision of the 21st Century Truck Partnership (21CTP) is at a high level, because it is beyond the scope of this is that the nationâs trucks and buses safely and cost-Âeffectively study to provide an in-depth review of all the DOT programs move larger volumes of freight and greater numbers of pas- covering commercial truck safety and safety regulation. The sengers while emitting little or no pollution and dramatically review is also restricted to projects related to on-board large reducing the dependency on foreign oil. Safety is a vital ele- truck technologies and systems. Nevertheless, the commit- ment of the program. The U.S. Department of Energy (DOE) tee suggests future work and outlines areas in which DOE transports hazardous materials across the nation in large and DOT collaboration might lead to improvements in large trucks. Ensuring the safety of these special trucks is critically truck safety. DOT defines a âlarge truckâ as one with a gross important to DOEâs mission. However, the majority of the vehicle weight rating (GVWR) of more than 10,000 pounds 21CTP budget is devoted to energy efficiency and vehicle (which includes vehicles that may be known in other contexts emissions reduction, and only a relatively small portion has as medium and heavy trucks). Finally, the committee notes been dedicated to safety-related technology. that its discussion focuses mainly on large trucks due to the Recent reductions in the overall 21CTP budget (discussed fact that the number of bus accidents and fatalities is much in Chapter 1) have limited the funding provided by DOE smaller in comparison. for safety research going forward. As such, DOE relies on the Department of Transportationâs (DOTâs) initiatives for Âprogress in the area of truck safety, since DOT has his- Goals and Timetables torically had responsibility for transportation safety. Indeed, DOT has established several specific goals for commer- although DOE and DOT have worked collaboratively in cial truck safety: certain areas with respect to truck safety, DOT has estab- lished a number of specific commercial truck safety goals, â¢ Reduce the fatality rate for heavy-duty trucks and but these goals have been established independent of the buses to 0.160 fatalities per 100 million total vehicle 21CTP. FurtherÂmore, DOT budget allocations in support of miles of travel by 2011. commercial trucks come from the various DOT agencies â¢ Develop and implement technologies for better brak- including the National Highway Traffic Safety Administra- ing, rollover protection, vehicle position, and visibility tion (NHTSA), the Federal Motor Carrier Safety Adminis- enhancement: tration (FMCSA), and the Federal Highway Administration âBraking. Advanced braking technologies will be (FHWA), and are also independent of the 21CTP. Each of sought with the research goal of achieving a reduction these DOT agencies has broad responsibility well beyond of stopping distances by 30 percent from operational the goals of the 21CTP. Consequently, the committee encountered some difficulty Personal communication (e-mail), Tim Johnson, DOT, NHTSA, June in addressing the subject of commercial truck safety. By vir- 12, 2008. tue of the future DOE budget allocation, the 21CTP includes Michael S. Griffith, FMCSA, âFederal Motor Carrier Safety Administra- very little on truck safety. Yet, DOT goals for commercial tion Safety Research Overview,â Presentation to the committee, Washington, D.C., February 9, 2007. 87
88 REVIEW OF THE 21ST CENTURY TRUCK PARTNERSHIP speeds in appropriate platforms. Improvement in and slowdowns, whose ultimate impact is increased fuel retention of braking ability during grade descents is consumption and vehicle emissions. desired. âRollover. Reduce the incidences of heavy vehicle The Nature of Heavy-Duty Truck and Bus Accidents rollover through the application of advanced technol- ogy brake control systems and other complementing The main focus of the committeeâs discussion is large technologies. trucks, because they contribute to an overwhelming majority âVehicle position. Develop and implement driver aid of accidents compared to buses. For example, in 2005 there systems that promote safe following distance and in- were 5,510 fatalities due to accidents involving large trucks lane tracking. and buses, but 5,212 of those fatalities were due to large âVisibility enhancement. Develop and implement sys- trucks (DOT, NHTSA, 2006a). tems that provide the operator with 360 degree visibil- In 2004, 12 percent of the total number of highway ity (direct and indirect) in day and night conditions. fatalities involved large trucks (over 10,000 pounds gross â¢ Work with tire manufacturers to improve truck tire vehicle weight), resulting in the death of 5,190 people (DOT, performance and reduce tire debris. Incorporate tire NHTSA, 2005a). In 2005 the number of fatalities due to advancements with improved braking technologies to large-truck crashes rose to 5,212, while another 114,000 achieve substantial vehicle handling improvements. people were injured in large-truck accidents (DOT, FMCSA, â¢ Determine the feasibility of enhanced occupant sur- 2007a). In 2006, the number dropped to 5,018 fatalities vivability in collisions (offset, frontal, and angle/Â (Transport Topics, 2007). Although the most serious results sideswipe) at differential speeds up to 35 mph between of highway accidents are the fatalities and injuries, there is heavy vehicles and passenger vehicles weighing also a significant cost to society associated with large truck approximately 4,000 pounds. Also, improvements and bus accidents. In one study, the medical costs, emergency will be sought in truck occupant seat belt use rates by service costs, property damage costs, lost productivity costs, harmonizing restraint systems requirements to enhance and the monetized value of the pain and suffering incurred comfort and, therefore, driver acceptability. by the families of those who die or are injured due to crashes were used to estimate the total cost of accidents. It was found that on average, the cost due to a large-truck crash was almost Research Priorities and Budget Allocation $60,000, while the average cost due to an inter city bus crash The committee asked DOE and DOT to provide a list of was over $32,000, based on 2000 dollars (Zaloshnja and projects and related funding, prioritized by potential impact Miller, 2002). on reducing fatalities and injuries relevant to large truck Large trucks pulling semi-trailers (Class 8) accounted and bus accidents. This request yielded only partial project for almost two-thirds of the truck-involved fatal crashes in lists, prioritized at the agency level (NHTSA, FHWA, and 2005 (DOT, FMCSA, 2007a). The majority of fatal accidents FMCSA), with too little information to give an overall pic- involved vehicleâto-vehicle crashes rather than single- ture of the safety programs or their funding trends. As a vehicle accidents. In 2005, the causes of fatal crashes were result, it was not possible for the committee to integrate the (1) large truck rear-ending passenger vehicle, 5 percent; patchwork of information to produce a clear picture of DOTâs (2) passenger vehicle rear-ending large truck, 16 percent; safety programs relevant to the 21CTP. This is another reason (3) large truck striking passenger vehicle (other than rear- the committee elected the approach of discussing the DOT e Â nding), 35 percent; and (4) passenger vehicle striking large safety program at a high level, as mentioned above. truck (other than rear-ending), 38 percent (DOT, FMCSA, The committee understands that individual agencies and 2007a). However, it is noteworthy that in 61.4 percent of the departments have responsibilities far beyond the subject of large truck fatality accidents, the initial point of impact with large-truck safety. Yet it appears that there is no single inte- the large truck was the front of the truck (DOT, FMCSA, grated list of truck safety projects prioritized by potential ben- 2007b, Table 42). efit. The committee addresses that topic later in this chapter. In fatal accidents involving heavy trucks and lighter vehicles, the fatality is most often an occupant of the lighter vehicle, due, obviously, to the size and weight differentials. Accidents Involving Large Trucks For example, in 2005, 92 percent of the fatalities due to such Before discussing progress toward achieving these DOT accidents were the occupants of the lighter vehicle (DOT, safety goals, the committee first reviews heavy-duty truck NHTSA, 2005a). and bus accidents, to characterize their general nature. It Although the number of heavy-duty trucks involved in then discusses how such accidents lead to traffic congestion fatal crashes per miles traveled declined, the total number of large trucks involved in fatal crashes increased from 4,472 to DOE, FCVT, response to committee queries on safety issues, transmitted 4,932 from 1995 to 2005, and the total number of fatalities via eâmail by Ken Howden, March 27, 2007. increased from 2004 to 2005 as noted above.
SAFETY OF HEAVY VEHICLES 89 Studies suggest that in many cases the accidents between from 1995 through 2005 on average only 21 school age chil- light and heavy vehicles are caused by the driver of the dren were fatalities in school transportation related crashes smaller vehicle. According to data collected by the Federal each yearâof that 21, typically 6 were occupants of school Motor Carrier Safety Administration (FMCSA), DOT, pas- transportation vehicles and 15 were pedestrians (DOT, senger vehicle drivers accounted for 66 percent of fatal NHTSA, 2005c, p. 1). accidents involving large trucks (DOT, FMCSA, 2007a). In a study of 210 accidents reported in 2002 by the University Impacts of Large-Truck Accidents on Fuel Consumption of Michiganâs Transportation Research Institute (UMTRI) and the Environment (Hanowski, 2002), the results suggested that 78 percent of the accidents were initiated by the light-vehicle driver. Fur- As described in the previous section, large truck crashes ther, the study concluded that â[a]ggressive driving on the are a major cause of accident fatalities and injuries in the part of the light vehicle driver was found to be the primary United States each year. That is reason enough for major contributing factor for light vehicle driver initiated incidents. efforts by industry and government to improve heavy truck For heavy vehicle driver initiated incidents, the primary con- highway safety. However, they also have direct impacts on tributing factor was poor driving technique.â fuel consumption and the environment. Accidents involv- In another study of heavy truck accidents, Blower found ing large trucks and buses create significant delays on our that 70 percent of the truck-car accidents were cause by the highways, particularly in congested areas. During these driver of the car (De Groat, 1999). However, in a study of delays, there are increases in fuel usage due to travel at heavy truck accidents in North Carolina, Council et al. (2003) low speeds and while sitting in traffic at idle. There is a found a more even distribution of fault, reporting that across corresponding increase in tailpipe emissions during these a broad spectrum of accident types, including accidents such times. In some cases, the accidents involve vehicles carry- as low-speed backing accidents, truck drivers account for ing hazardous materials, creating an even more dangerous slightly more accidents than car drivers: 48 percent for truck situation, and in certain cases, potential issues related to drivers and 40.2 percent for drivers of cars. national security. Accident causation has been a focus of research for Of course, accidents also contribute to costs associ- many years. It is well known that for accidents leading to ated with lost work time by commuters. Indeed, highway fatalities, considering all vehicle typesânot just heavy congestion, even in the absence of an accident, is a serious trucksâÂalcohol or speeding are often causal factors, with problem in the United States and in many large cities around a Â lcohol involvement cited in about 40 percent of fatal acci- the world. The Texas Transportation Institute (TTI) tracks dents during the past 10 years, and speeding a factor in about congestion data for the 85 largest cities in the United States 30 percent of fatal accidents over the same period of time (http://tti.tamu.edu/). According to TTI, in 2003, in the com- (DOT, NHTSA, 2006a). However, alcohol and speeding are bined total of the 85 cities, there was travel delay of about most often attributed to the driver of the vehicle other than 3.7 billion hours, associated with which there was excess the heavy truck (e.g., 22 percent of car drivers involved in fuel consumption of 2.258 billion gallons of fuel. Elements fatal accidents were speeding while 7 percent of large truck contributing to congestion include heavy traffic, highway drivers involved in fatal accidents were speeding). A recent construction and repair, and roadway incidents including report on large truck accident causation cites a variety of accidents (Texas Transportation Institute, 2007, Table 2). factors including driver fatigue, falling asleep, inattention, A recent report prepared by the Volpe Center, DOT driving too fast for conditions, and physical impairment due (Flieger et al., 2007), the authors provide estimates of the to illness (DOT, NHTSA, 2006c). impact of commercial vehicle crashes on fuel economy and Compared with heavy-duty trucks, the number of people emissions. The authors project that each commercial motor killed in accidents involving medium-duty single-unit trucks vehicle (CMV) crash leads to additional fuel consumption of is much smaller than the aforementioned case of large-truck from almost 800 gallons to as much as 1,200 gallons depend- accidents (300 fatalities in 2005 for classes 5 and 6 com- ing on the level of congestion prior to the crash. Estimating bined, for example) due to the fact that these medium-duty extra emissions caused by CMV crashes is extremely dif- trucks typically operate at lower speeds, in an urban area, and ficult due to the variation of the factors involved. However, during daylight (DOT, NHTSA, 2006c, p. 59). the Volpe report estimates that over a year, CMV crashes in Bus accidents account for a much smaller percentage the major metropolitan areas in the United States produce of fatalities and injuries. For instance, in 2005, there were significant levels of emissions: CO on the order of 100,000 a total of 278 bus accident related fatalities, representing tons, and NOx on the order of 14,000 tons. Perhaps of more only 0.5Â percent of all highway vehicle fatalities for that consequence, most of these emissions are localized in urban year (DOT, NHTSA, 2005a). Moreover, school-bus travel areas, thereby aggravating local health issues. Clearly, continues to be quite safe compared to travel in most other improvements in CMV safety will contribute to reduction in highway vehicles. Although any child fatality is a tragedy, fuel consumption and exhaust emissions.
90 REVIEW OF THE 21ST CENTURY TRUCK PARTNERSHIP Goal 1: Reduce the large-truck and bus unique to large truck accidents; highway fatalities due to fatality rate to 0.160 per 100 million total all types of accidents have remained constant over the past vehicle-miles by 2011 decade. In fact, although the number of fatalities per miles traveled has decreased, the total number of fatalities has The information in this section clearly shows that large increased slightly from 40,716 in 1994 to 43,443 in 2005 truck accidents are a very serious problem in the United (FARS data online). States, causing major loss of life, thousands of serious inju- On the other hand, there has also been a decrease in the ries, and substantial property damage. Moreover, although rate of large-truck-related accidents as the number of vehicle some improvement has occurred since the highs of 1997, miles traveled has increased steadily. Thus, improvements 1998, and 1999, the total number of deaths due to large truck in highway safety have been observed. Figure 7-2 shows accidents seems to remain in the neighborhood of 5,000 per the fatality rate for large truck and bus accidents from 1995 year, and was higher in 2004 and 2005 than it was as long to 2005. The fatality rate has declined from 0.215 to 0.184 ago as 1994, as is shown in Figure 7-1. This trend is not during that time period while the total vehicle miles traveled 5400 5300 Number of Deaths 5200 5100 5000 4900 4800 4700 4600 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Year FIGURE 7-1â Deaths due to large-truck accidents. SOURCE: Data from DOT, NHTSA, Fatality Analysis Reporting System. Available at www.fars.nhtsa.dot.gov/ Accessed May 13, 2008. Fig 7-1 0.250 Fatality Rate per 100 Million Total Vehicle Miles Traveled 0.200 0.150 0.100 0.050 0.000 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Year FIGURE 7-2â Large-truck and bus fatality rate (per 100 million total vehicle miles traveled). SOURCE: Michael Griffith, DOT, FMCSA, August 29, 2007. Large Truck and Bus Fatality Rates, 1995-2005. Personal communication to the committee. Fig 7-2
SAFETY OF HEAVY VEHICLES 91 has increased from 2,422,696 to 2,989,807, a 23 percent Goal 2: Crash Avoidance increase. As noted earlier, compared to bus accident related (e.g., Braking, RollOver Avoidance, Vehicle fatalities, large truck accidents contribute the most to high- Position Control and Monitoring, Visibility way fatalities by a large margin (~95 percent of fatalities). Improvements, and Tire Performance) Although the rate has improved, unfortunately, we have As mentioned above, it may be that we are seeing dimin- not seen a significant decrease in the number of large truck ishing returns with respect to further improvements in crash accident related fatalities in spite of the fact many resources protection; perhaps other, further benefits might come from have been directed at making improvements in vehicle safety. 100 percent seat belt usage on the road. Crash avoidance has Earlier efforts were focused on crash protection, including become, thus appropriately, the overarching next generation improvements in structural crashworthiness and occupant goal. protection. Increased usage of seat belts both in trucks and cars provides enhanced survivability. In light vehicles, the increased usage of air bags further enhances survivability in Programs more severe crashes. One might conclude that crashworthiness improve- Braking ments have merely offset the increase in accidents due to DOE and DOT are working toward improvements in brak- the increase in total miles driven, and that we will have to ing to achieve a reduction by 30 percent in stopping distance, reduce the number of crashes through accident avoidance by considering the application of air disc brakes, more pow- technologies in order to significantly reduce the number erful front-axle brakes, and electronic control (DOE, 2006). of fatalities. To this end, DOT has been putting more focus In addition, work is ongoing at DOE laboratories to develop on accident prevention. Crash avoidance topics relative to improved properties in brake materials. vehicle modifications include improvements in braking; The Department of Transportation is sponsoring several rollover reduction; vehicle position (safe following, lane studies at DOE laboratories (DOE, 2006, p. 52). NHTSA has tracking); visibility enhancement; and tire safety. However, initiated several brake related studies at Oak Ridge National as the committee noted earlier in this chapter, most accidents Lab (ORNL). A study on standardizing the rating of brake are due to driver error. Moreover, in 2005 there were 14,539 friction materials is aimed at maintaining standard capabili- car and truck fatalities due to crashes in which alcohol was ties in new and replacement brakes. Additional research is a factor (DOT, NHTSA, 2006a). Therefore it will be impor- focused on testing brake materials on test tracks to correlate tant to assess the potential benefit of vehicle modifications material properties with brake performance. to determine whether or not DOTâs goals for fatality rate The Federal Highway Administration (FHWA) has initiated reduction can be met. a study at ORNL aimed at improving the accuracy of truck brake simulations by incorporating the effects of temperature, Finding 7-1. The DOE program director of the 21st Century humidity and braking torques on brake performance. Truck Partnership has no direct authority for heavy-duty truck safety projects because there is no budget in the pro- gram itself to support safety projects. The program manager Rollover Prevention will need to continue to work with DOT, because DOT has The objective is to reduce the incidences of heavy vehicle several initiatives with the goal of making improvements in rollover through applications of advanced braking systems and heavy-duty truck safety. They range from driver education other technologies. NHTSA is working with industry using to accident avoidance technology. However, the committee currently available commercial hardware to determine the was unable to determine whether the goals would be met as effectiveness of roll stability systems and yaw stability control a result of these initiatives. systems on tractors, and roll stability systems on Âtrailers (Evans et al., 2005). In addition, NHTSA has sponsored work at the Recommendation 7-1. DOT should develop a complete and University of Michigan Transportation Research Institute on comprehensive list of current and planned heavy-duty truck a hardware in the loop simulation study of electronic control safety projects and initiatives, and prioritize them in order of systems, and has recently awarded an electronic stability con- potential benefit in reducing heavy-duty truck-related fatali- trol (ESC) driving simulator study to the National Advanced ties. The list should provide quantitative projections of fatality Driving Simulator at the University of Iowa. reduction potential attributable to each project. The list should also be used to prioritize budget and resource allocations, in order to expedite heavy-duty truck safety progress. Tim Johnson, DOT, NHTSA, âNHTSA Heavy Vehicle Research Over- view,â Presentation to the committee, Washington D.C., February 8, 2007, Slide 6. Tim Johnson, DOT, NHTSA, âNHTSA Heavy Vehicle Research Over- Tim Johnson, DOT, NHTSA, âNHTSA Heavy Vehicle Research Over- view,â Presentation to the committee, Washington D.C., March 28, 2007, view,â Presentation to the committee, Washington D.C., March 28, 2007, Slide 6. Slide 6.
92 REVIEW OF THE 21ST CENTURY TRUCK PARTNERSHIP Vehicle Position Control The committee noted in this chapter that 7 percent of heavy truck drivers were speeding in accidents that led to Research in this area includes studies of both forward a fatality. Some trucking companies employ speed control c Â ollision warning to prevent rear impacts, and side-to-side governors to prevent speeding. Reduced speed also reduces lane departure warning. Both NHTSA and FMCSA have fuel consumption. been heavily involved in research in these areas. In coopera- DOTâs Intelligent Transportation Systems Program (ITS) tion with industry, electronically controlled brake systems, is broad in scope, touching on road design and operation, collision warning systems, and adaptive cruise control sys- vehicle technologies, human factors research and in-vehicle tems are being evaluated to determine their effectiveness. In as well as inter-vehicle communications. The ITS programs addition, on-board monitoring systems are being investigated involve not only federal government agencies, but also heavy to determine their effectiveness in alerting drivers who might and light vehicle manufacturers, state and local governments, become drowsy or distracted. and contract research groups including universities. The ITS program is beyond the scope of this report. How- Visibility ever, we note that many aspects of ITS support the objective of accident avoidance. Furthermore, ITS is broad in vehicle According to NHTSA, one of the largest causes of large scope, potentially covering communications among all high- truck crashes results from lane changing and merging with way vehicles; this could be an important element in helping other traffic. In many cases the accident is caused by the to prevent large truck crashes with light vehicles. truck driver not being able to see areas that are blind spots. It is also beyond the scope of this study to evaluate the In cooperation with FMCSA, NHTSA is exploring the use work being done in support of our roads, bridges, and road of video mirrors to eliminate truck blind spots. Longer range infrastructure. However, the road system and its condition potential research topics could include advanced night vision critically influence highway safety. systems and head up displays, according to the 21CTP R Â oadmap (DOE, 2006). Progress Toward Goals Tire Performance Braking The objective is to work with tire manufacturers to improve Several high-technology tractor-trailer trucks have been truck tire performance and to reduce roadway tire debris built that have demonstrated stopping distance reduction on (DOE, 2006). It will be important to couple tire behavior the order of 30 percent. This result has been achieved using with improved braking technology to optimize vehicle stop- air disc brakes. The use of these brakes will also improve the ping distance as well as handling. NHTSA plans to research fade resistance of large truck brake systems. Cost will be an improvements to FMVSS 119 relative to endurance and high issue with respect to rapid deployment (DOE, 2006, p.Â 1). speed tires, with emphasis on identification of the frequency In a DOT Field Operational Test (FOT) involving Volvo, test and failure mode of both new and retread heavy vehicle). results validated the improvement in stopping distance using Additional studies include methods for monitoring tire disc brakes, and also showed that the disc brakes have longer pressure and the effects of replacing standard dual tires with useful life compared with drum brakes (Volvo Trucks North single tires on truck tractors. America, 2005). In the area of tire mechanics, it is important for DOE and DOT to work closely together, to ensure that changes that lead to reduced rolling resistance donât compromise safety. Rollover Prevention In a field operational test involving six Freightliner tanker Other Focuses trucks, an in-cab system was evaluated. The system indicates to the driver what the rollover threshold is of the combina- Improving driver performance is, of course, an important tion truck-trailer, and how close to that threshold the vehicle approach to preventing accidents. Driver fatigue has been is at any instant in time. As a result of data analysis, it was cited as an important factor leading to accidents, and the concluded that the driver advisor system reduced the overall National Transportation Safety Board has proposed the use chance of rollover by from 20 to 30 percent for âtoo fast of on-board recorders to ensure that drivers comply with around the curveâ types of potential rollover (DOE, 2006, rules regarding hours of service. p. 61). Tim Johnson, DOT, NHTSA, âNHTSA Heavy Vehicle Research Over- view,â Presentation to the committee, Washington D.C., February 8, 2007, Slide 4. Michael F. Trentacoste, DOT, FHWA, âSafety R&D Overview,â Mark V. Rosenker, âOn-Board Recorders (EOBRâs) and Truck Drivers P Â resentation to the committee, Washington, D.C., February 8, 2007, Slides Fatigue Reduction,â Presentation to the U.S. Senate, May 1, 2007. 5 and 6.
SAFETY OF HEAVY VEHICLES 93 Vehicle Position Control working with suppliers, have developed on-board systems for enhancing roll and yaw stability, for improving straight line Two different field operational tests have been completed braking performance, for collision warning, and for alerting and provide results relative to vehicle position control. drivers relative to lane departure. In cooperation with DOT, A field operational test in cooperation with Mack Trucks many of these systems have been or are being evaluated in studied the performance of on-board lane departure warning FOTs, and results are being reported. systems. The Volvo FOT mentioned earlier included systems for collision warning, adaptable cruise control, and elec- Finding 7-2. Programs are underway to develop and imple- tronically controlled braking systems.10 According to DOT, ment technologies and vehicle systems to support safety the lane departure warning systems, under FOT conditions, goals. Indeed, private industry, through internal research and provided a 21 percent to 23 percent reduction in accidents commercial product development, has produced commer- for single vehicle roadway departure, and a 17 to 24 percent cially available systems for enhanced braking, roll stability, reduction in rollovers (DOT, FMCSA, 2006). The Volvo FOT and lane departure warning. They are beginning to be used (Volvo Trucks North America, 2005) showed that it could in the field. It is now important to determine to what extent be possible to reduce rear impacts by 28 percent by using a these accident avoidance technologies will reduce the num- combination of collision warning, adaptive cruise control, ber of accidents and therefore fatalities and injuries. and electronic braking. Recommendation 7-2. DOT should continue programs in Visibility support of heavy-duty truck onboard safety systems, with an emphasis on accident avoidance and with priorities set Performance specifications for camera/video imaging by a comprehensive potential cost/benefit analysis (Recom- systems are expected to be completed in September 2007. mendation 7-1). Particular emphasis should be placed on In September 2008, the development and assessment of a monitoring the accident experience of heavy-duty trucks as 360 degree vision system capable of operating in all weather these systems begin to be deployed in the field (for example, conditions should be completed. as electronic stability control systems begin to penetrate the fleet). It is the role of the manufacturers to develop safety Tire Performance systems for commercial application. DOT can play important roles in (1) providing support for field tests (known to DOT NHTSA is working with the American Society for Test- as field operational tests), (2) monitoring field data to help ing and Materials and tire companies on the aforementioned substantiate benefit analyses used to prioritize resources, programs. Results are expected in 2007. and (3) implementing regulations that would require the Researchers at ORNL have been studying the benefits of adoption of safety systems that were proved to be effective. using a single tire to replace two thinner tires on heavy duty With adequate field data, DOT should refine and more rig- tractor trailer trucks. They have found that the single tire orously specify and prioritize goals for accident avoidance improves fuel economy by as much as 3 percent and also technologies. allows them to be run with more stability.11 Tire pressure monitoring systems are being developed to ensure proper pressures on truck tires. Keeping tires properly Appropriate Roles for DOT in Accident Avoidance inflated maintains safety performance and improves fuel Technology Development and Deployment, and economy by reducing tire rolling resistance. In a study of Other Areas of Vehicle Safety light vehicle tires, it was found that a 10 percent reduction The Department of Transportation plays an important in average rolling resistance could yield a 1 to 2 percent role in large truck safety by establishing safety requirements improvement in fuel economy and that this could be done for new vehicles, by licensing commercial drivers, and by without sacrificing safety (NRC, 2006). ensuring that safe practices are used once the vehicles are in service. In addition to this regulatory role, DOT can promote Summary of Performance highway safety by working with original equipment manu- facturers, suppliers, other government agencies, including A number of programs are currently in progress to advance DOE, and others in helping to evaluate the effectiveness the individual goals of crash avoidance. These programs are of newly developing large truck safety systems. The field in various states of completion, with some having reached operational tests are an example of how DOT is currently milestones. During the past several years, large truck OEMs, doing this. Furthermore, DOT can play an important and unique role by monitoring the field performance of truck 10Tim Johnson, DOT, NHTSA, âNHTSA Heavy Vehicle Research safety systems to accurately assess the cost-benefit of such Overview,â Presentation to the committee, Washington D.C., March 28, systems and by identifying any deficiencies in the systems. 2007, Slide 6. 11See www.greencarcongress.com/2006/06/single_widebase.html. Finally, DOT can monitor safety initiatives and practices
94 REVIEW OF THE 21ST CENTURY TRUCK PARTNERSHIP around the world, and use this information along with its alter the vehicle configuration and therefore its crashworthi- own studies to suggest future work that might further the ness. Moreover, as new fuel efficient systems emerge, such goals of highway safety. as hybrid electric systems, and vehicles using alternate fuels including, for example, hydrogen, it will be imperative that DOE and DOT work closely to ensure continued progress Goal 3: CrashWorthiness Research toward more fuel efficient vehicles but without compromis- (Survivability) ing highway safety. The crashworthiness of heavy duty trucks is an area in which close collaboration between DOE and DOT is critical. Benefits of 21st Century Truck Partnership Structural changes to the truck for weight reduction might Safety Research be suggested for fuel economy savings as part of the 21CTP. It must also comprehend how the application of lightweight Due to the relatively large number of fatalities and inju- materials would affect the structural crashworthiness of the ries suffered as a result of large truck accidents, it is entirely vehicle. Any modification to the exterior shape for improve- appropriate to consider many different safety technologiesâ ments in safety could also affect the aerodynamic perfor- in fact it may require an integrated system of technologies to mance of the vehicle and thus its fuel efficiency. As a specific make a large impact on the problem. For example, NHTSA example, it was noted (DOE, 2006) that the addition of the has shown that a 30 percent improvement in stopping dis- rear under-ride guard to truck trailers adversely impacted the tance due to enhanced braking capability, could lead to a aerodynamic performance by increasing vehicle drag. reduction of 257 fatalities.12 Unfortunately, this represents In addition to considering the crashworthiness of the only a 4.9 percent reduction in fatalities related to large truck heavy truck for the sake of protecting the truck driver, DOT accidents based upon the number of fatalities reported in should further explore the truck design from the standpoint of 2005, illustrating the point that significant improvements in its aggressiveness in a collision with smaller vehicles. As the truck safety are still needed. committee noted in the section entitled âAccidents Involv- The aforementioned discussion raises the obvious need ing Large Trucks,â more than half of the fatal accidents in for the development of an analysis of the numerous safety which a heavy truck collided with another vehicle involved technologies under consideration, to be used to prioritize contact with the front of the truck, suggesting this as an area projects and funding. FMCSA has provided a list of large for additional study with respect to alternate materials and truck safety systems being applied and their approximate under-ride guards. retail prices.13 Finding 7-3. In spite of extensive improvements in light â¢ Roll stability control systems vehicle crashworthiness made during the past decade, the âTractor based system: ~$500 above cost of traction number of fatalities caused by heavy-duty truck accidents control has remained nearly constant, at approximately 5,000 per âTrailer based system: ~ $1,000-$1,500 year, although the fatality rate has decreased showing that â¢ Electronic stability control systems: ~$1,500-$2,100 progress is being made. In most cases, the occupant(s) of the â¢ Lane departure systems: ~$700-$1,500 light vehicle is the one fatally injured. It appears that to make â¢ Collision warning systems: ~$700-$5,000 depending significant safety progress, it will be necessary to reduce the on options number of accidents substantially by implementing accident avoidance technologies as well as methods for improving Continued development should bring down these costs over driver behavior. In light of this need, DOT future plans have time. However, there is only cursory and incomplete infor- been directed largely at accident avoidance technologies. mation available at this time to indicate to what extent the incorporation of all of these and other safety technologies Recommendation 7-3. The committee agrees with the will lead to the overall safety goals for fatality reduction for apparent decision by DOT to put more emphasis on accident large truck and bus accidents as set by DOT. avoidance technologies than on additional crashworthiness NHTSA has addressed the potential benefits of electronic research. In addition, DOT should continue to focus on stability control (ESC) systems applied to passenger cars, driver education and law enforcement. Furthermore, DOE multipurpose vehicles, and trucks and buses with a gross and DOT should work collaboratively, because there often vehicle weight rating of 4,536 kg (10,000 lb) or less. Based are trade-offs between vehicle safety and fuel economy, on crash data studies, NHTSA estimates that the use of ESC for example, as new fuel efficient systems emerge. There will reduce single-vehicle crashes of SUVs by 59Â percent and are obvious trade-offs between safety and fuel economy in 12DOE, FCVT, response to committee queries on safety issues, transmit- many areas of research such as tire mechanics and braking (especially with respect to hybrid vehicles). Of course, any ted via eâmail by Ken Howden, March 27, 2007. 13DOE, FCVT, response to committee queries on safety issues, transmit- additional work in aerodynamics or weight reduction might ted via eâmail by Ken Howden, March 27, 2007.
SAFETY OF HEAVY VEHICLES 95 reduce rollovers by 84 percent. Overall, the annual potential DOT, FMCSA. 2007b. Large Truck Crash Facts 2005. Pub. No. benefit of ESC applied to these vehicles is estimated to be FMCSA-RI-07-046. February. Available at http://ai.volpe.dot. gov/ÂCarrierResearchResults/PDFs/LargeTruckCrashFacts2005.pdf. 5,300 to 10,300 lives saved and prevention of 168,000 to A Â ccessed May 13, 2008. 252,000 injuries in all types of light vehicle crashes (DOT, DOT, NHTSA (National Highway Traffic Safety Administration). 2005a. NHTSA, 2006b). No comparable analysis of the potential Traffic Safety Facts. Pub. No. DOT HS 810 616. Available at http:// benefit of ESC applied to heavy trucks has been found. www-nrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/TSF2005/810616.pdf/. However, the fact that there are over 15,000 rollovers of A Â ccessed May 30, 2008. DOT, NHTSA 2005b. Traffic Safety Facts. Large Trucks. Pub. No. DOT HS commercial trucks each year accounting for 12 percent of 809 907. Available at http://www-nrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/ fatalities (UMTRI Research Review, 2000) suggests that TSF2004/809907.pdf. Accessed March 24, 2008. there is a large potential benefit. It is encouraging at this time DOT, NHTSA. 2005c. Traffic Safety Facts. School Transportation-Related that heavy truck manufacturers and component suppliers are Crashes. Pub. No. DOT HS 810 626. Washington, D.C. making stability control systems available on new trucks. DOT, NHTSA. 2006a. Large-Truck Crash Causation Study: An Initial Over- view. Pub. No. DOT HS 810 646. Washington, D.C. August. In addition to the aforementioned systems, it would be DOT, NHTSA. 2006b. Proposed FMVSS No. 126. Electronic Stability helpful to have similar analyses of other technologies under Control Systems. Washington, D.C. August. consideration. For example, the ITS technologies, including DOT, NHTSA. 2006c. Traffic Safety Facts 2005. Pub. No. DOT HS 810 vehicle-to-vehicle communications, will permit communica- 631. Washington, D.C. tion between large commercial trucks and passenger cars and Evans, Jeffrey L., Stephen A. Batzer, and Stanley B. Andrews. 2005. Evalu- ation of Heavy Truck Rollover Accidents. Report prepared by Renfroe trucks, perhaps leading to substantial reduction in accidents. Engineering, Inc., for the National Highway Traffic Safety Administra- But it is important to know what improvements in safety will tion. Paper No. 05-0140. Available at http://www-nrd.nhtsa.dot.gov/pdf/ likely come from these technologies. nrd-01/esv/esv19/05-0140-W.pdf. Accessed June 3, 2008. In conclusion, a benefit analysis for any system under con- Flieger, T. F., A. Klauber, J. Mantilla, and Paul Zebe. 2007. 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University of Michigan Record, News and InforÂ Available at http://mobility.tamu.edu/ums/congestion_data/tables/Â mation Services. November. 8. Available at http://www.ur.umich. national/table_2.pdf . Accessed June 2, 2008. edu/9900/Nov08_99/18.htm. Accessed March 24, 2008. Transport Topics. 2007. Safety Technologies Play Greater Role in Prevent- DOE (U.S. Department of Energy). 2006. 21st Century Truck Partnership ing Truck-Related Crashes. June 4. Roadmap and White Papers. Pub. No. 21CTP-003. Washington, D.C. UMTRI Research Review. 2000. Vol. 31, No. 4 (October-December). December Volvo Trucks North America. 2005. ITI Field Operational Test. Evalu- DOT (U.S. Department of Transportation), FMCSA (Federal Motor ÂCarrier ation of Advanced Safety Systems for Heavy Truck-Trailers. Doc. Safety Administration). 2006. Lane Departure Warning Systems and No. 07-0212. February. 15. Available at http://www.itsdocs.fhwa.dot. Deployment. 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