speeds in appropriate platforms. Improvement in retention of braking ability during grade descents is desired.
Rollover. Reduce the incidences of heavy vehicle rollover through the application of advanced technology brake control systems and other complementing technologies.
Vehicle position. Develop and implement driver aid systems that promote safe following distance and inlane tracking.
Visibility enhancement. Develop and implement systems that provide the operator with 360 degree visibility (direct and indirect) in day and night conditions.
Work with tire manufacturers to improve truck tire performance and reduce tire debris. Incorporate tire advancements with improved braking technologies to achieve substantial vehicle handling improvements.
Determine the feasibility of enhanced occupant survivability in collisions (offset, frontal, and angle/ sideswipe) at differential speeds up to 35 mph between heavy vehicles and passenger vehicles weighing approximately 4,000 pounds. Also, improvements will be sought in truck occupant seat belt use rates by harmonizing restraint systems requirements to enhance comfort and, therefore, driver acceptability.
The committee asked DOE and DOT to provide a list of projects and related funding, prioritized by potential impact on reducing fatalities and injuries relevant to large truck and bus accidents. This request yielded only partial project lists, prioritized at the agency level (NHTSA, FHWA, and FMCSA), with too little information to give an overall picture of the safety programs or their funding trends.3 As a result, it was not possible for the committee to integrate the patchwork of information to produce a clear picture of DOT’s safety programs relevant to the 21CTP. This is another reason the committee elected the approach of discussing the DOT safety program at a high level, as mentioned above.
The committee understands that individual agencies and departments have responsibilities far beyond the subject of large-truck safety. Yet it appears that there is no single integrated list of truck safety projects prioritized by potential benefit. The committee addresses that topic later in this chapter.
Before discussing progress toward achieving these DOT safety goals, the committee first reviews heavy-duty truck and bus accidents, to characterize their general nature. It then discusses how such accidents lead to traffic congestion and slowdowns, whose ultimate impact is increased fuel consumption and vehicle emissions.
The main focus of the committee’s discussion is large trucks, because they contribute to an overwhelming majority of accidents compared to buses. For example, in 2005 there were 5,510 fatalities due to accidents involving large trucks and buses, but 5,212 of those fatalities were due to large trucks (DOT, NHTSA, 2006a).
In 2004, 12 percent of the total number of highway fatalities involved large trucks (over 10,000 pounds gross vehicle weight), resulting in the death of 5,190 people (DOT, NHTSA, 2005a). In 2005 the number of fatalities due to large-truck crashes rose to 5,212, while another 114,000 people were injured in large-truck accidents (DOT, FMCSA, 2007a). In 2006, the number dropped to 5,018 fatalities (Transport Topics, 2007). Although the most serious results of highway accidents are the fatalities and injuries, there is also a significant cost to society associated with large truck and bus accidents. In one study, the medical costs, emergency service costs, property damage costs, lost productivity costs, and the monetized value of the pain and suffering incurred 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 $60,000, while the average cost due to an inter city bus crash was over $32,000, based on 2000 dollars (Zaloshnja and Miller, 2002).
Large trucks pulling semi-trailers (Class 8) accounted for almost two-thirds of the truck-involved fatal crashes in 2005 (DOT, FMCSA, 2007a). The majority of fatal accidents involved vehicle–to-vehicle crashes rather than single-vehicle accidents. In 2005, the causes of fatal crashes were (1) large truck rear-ending passenger vehicle, 5 percent; (2) passenger vehicle rear-ending large truck, 16 percent; (3) large truck striking passenger vehicle (other than rear-ending), 35 percent; and (4) passenger vehicle striking large truck (other than rear-ending), 38 percent (DOT, FMCSA, 2007a). However, it is noteworthy that in 61.4 percent of the large truck fatality accidents, the initial point of impact with the large truck was the front of the truck (DOT, FMCSA, 2007b, Table 42).
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. For example, in 2005, 92 percent of the fatalities due to such accidents were the occupants of the lighter vehicle (DOT, NHTSA, 2005a).
Although the number of heavy-duty trucks involved in fatal crashes per miles traveled declined, the total number of large trucks involved in fatal crashes increased from 4,472 to 4,932 from 1995 to 2005, and the total number of fatalities increased from 2004 to 2005 as noted above.