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28 submitted a petition in 2006 requesting that FMCSA require icant driver productivity losses if speeds were reduced from 75 manufacturers to allow the adjustment of speed-limiting de- mph to lower levels. For a more detailed discussion of the ef- vices to no more than 68 mph on all new trucks over 26,000 fects of truck speed policies, see Appendix B. pounds GVW.7 Approximately 77 percent of ATA's members have speed limiters set at 68 mph or lower.8 The Province of Unexpected Impacts Ontario recently passed a law requiring trucks with a model year of 1995 or newer to be speed limited at 65 mph, and the The fuel economy impacts of the 1973 law were overesti- Province of Quebec has adopted similar rules.9 mated because lawmakers did not consider the effects of non- compliance. With respect to the recent increase in highway speed limits, the negative effects of differential speed limits Policy Impacts were not fully expected by legislators and policymakers. The The safety impact of lowering speed limits and creating dif- safety benefits of these policies have yet to be conclusively ferential speed limits for cars and trucks has been the subject documented with scientific studies. Nonetheless, many indus- of debate among researchers and policymakers. Research try safety managers are proponents of reducing truck speeds clearly finds that lower vehicle speeds reduce the severity of based on their firms' experience. crashes and the incidence of fatalities.10 Lower speeds also im- A potential unexpected impact of governing speed could be prove truck-braking distances. On the other hand, differen- higher driver turnover, because many drivers oppose the use of tial speeds caused by lower speed limits can increase crash speed governors, especially when drivers are paid by the mile risk. Many researchers have argued that it is the speed differ- or trip. If driver turnover increases and results in experienced ence between vehicles, not the absolute speed, that is most drivers being replaced with inexperienced drivers, this could important for creating crash risk. Trucks traveling at speeds increase safety risk. Surveys of drivers have also suggested that lower than the rest of traffic interact with more vehicles, in- being speed limited at lower speeds can cause fatigue in drivers creasing risk. In addition to the car-truck differential, speed on long trips. Drivers will obviously be on the road for less time limits over 65 mph tend to increase speed differentials be- if they travel at higher speeds. Speed-limited drivers also ex- tween trucks by dividing trucks into company drivers (who pressed frustration at being trapped in the right-hand lane and tend to be speed limited at lower levels) and owner-operators being forced to constantly deal with merging traffic.12 (who typically can travel at higher speeds). Overall, researchers and policymakers have not reached consensus on the impact Aircraft Fuel Tank of differential speeds. Flammability Rules Regarding mandatory truck speed governors, large truck- ing companies, many represented by ATA, are supportive; Policy Description they argue mandatory truck speed governors improve safety, Since 1960, 18 airplanes have been damaged or destroyed reduce fuel consumption, and lower vehicle maintenance as the result of fuel tank explosions. Such an explosion was costs. Small owner-operators represented by the Owner Oper- determined to be the cause of the 1996 crash of TWA Flight ator Independent Drivers Association (OOIDA) have opposed 800 off Long Island, New York. This accident resulted in the the ATA speed limiter proposal, arguing that it is a public re- death of all 230 people aboard. Although investigators have lations stunt by large businesses that could disadvantage not always identified the ignition source of these explosions, small firms.11 There are also regional differences in firms' for some of the most recent incidents, investigators deter- view of truck speeds. Interview respondents noted that truck- mined that the explosion involved empty or nearly empty ing firms with major western operations would suffer signif- center-wing fuel tanks that contained flammable vapors when the fuel tanks exploded.13 In response to these incidents, FAA issued a final rule in July 7ATA, "Petition for Rulemaking before the National Highway Traffic Safety Ad- 2008 that requires manufacturers and operators of certain jet ministration (NHTSA) to amend 48 CFR Part 571 to Require Vehicle Manufac- aircraft (both new and existing) to meet performance require- turers to Install Speed Limiting Devices Set at No More than 68 MPH on New Trucks with a GVWR of Greater than 26,000 Pounds," 2006. ments for reducing fuel tank flammability to an acceptably 8"Truckers Back a National 65-mph Speed Limit," U.S. News and World Report, safe level.14 Although the rule does not direct the adoption of March 26, 2008. 9"Ontario to Require 65-MPH Speed Limiters on Trucks," Transport Topics, June 18, 2008. 10TRB, Safety Impacts of Speed Limiter Device Installations on Commercial Trucks 12Johnson and Pawar, November 2005. and Buses: A Synthesis of Safety Practice, 2008. 13FAA, "Reduction of Fuel Tank Flammability in Transport Category Airplanes," 11OOIDA, "OOIDA Accuses Feds of Pandering to Big Business by Toying with Notice of Final Rule, July 21, 2008, 73 FR 42445. Speed Limiter Idea," press release, January 26, 2007. 14FAA, 73 FR 4244442504.