Do Higher Speed Limits Cause Accidents, What About All The Studies From The US? 

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Charles Lave and Patrick Elias. "Did the 65 MPH Speed Limit Save Lives?" Accident Analysis and Prevention, 26.1 (1994), p. 49.
"We find that the 65 mph limit reduced statewide fatality rate by 3.4% to 5.1%, compared to those states that did not raise their speed limit."

"As might be expected, there have been numerous studies of the new speed limit.... Most of these studies looked at the number of fatalities, before and after the increase to 65 mph. The number usually increased since traffic usually increased - but we should be looking at rates, i.e. fatalities per vehicle mile traveled..."

Charles Lave and Patrick Elias. "Did the 65 MPH Speed Limit Save Lives?" Accident Analysis and Prevention, 26.1 (1994), p. 61.
"Why did the new speed limit lower the fatality rate? (i) Drivers may have switched to safer roads... (ii) highway patrols may have shifted resources to activities with more safety payoff... (iii) ... it is also possible that the new law caused a decline in speed variance; it might decline on the interstates as law-abiding drivers caught up with the speeders, and it might decline on other highways as their speeders switched to the interstates."

Prahlad D. Pant, Jamal A. Adhami, and John C. Niehaus. "Effects of the 65-mph Speed Limit on Traffic Accidents in Ohio." Transportation Research Record, 1375 (1992), pp. 53+
"It was found that fatal accident rates on rural Interstate highways posted at 65 mph or rural non-Interstate highways posted at 55 mph had not significantly changed after the implementation of the 65-mph speed limit."

Gang-Len Chang, Everett C. Carter, and Chao-Hua Chen. "Safety Impacts of the 65-mph Speed Limit on Interstate Highways" AAA Foundation for Traffic Safety, 1991 August, p. iv.
"...the increased speed limit had significant initial impacts on highways fatalities at the nationwide level. Such impacts, however, decayed over time after about a one-year 'learning period'."

"... the level of impacts is far less than that claimed by some studies reported in the literature."

Nicholas J. Garber and Ravi Gadiraju. "Impact of Differential Speed Limits on the Speed of Traffic and the Rate of Accidents." Transportation Research Record, 1375 (1992), p. 44.
"There is no evidence that the increase in the maximum speed limit to 65 mph for passenger vehicles on the rural Interstate systems in the states studied has directly resulted in a significant increase in fatal, injury, or overall accident rates."

Charanjit S. Sidhu. "Preliminary Assessment of the Increased Speed Limit on Rural Interstate Highways in Illinois." Transportation Research Record, 1281 (1990), p. 78.
"Results indicate that the higher posted speed limit in Illinois did not have a clearly noticeable or an obviously adverse effect on fatal accidents during its first year."

R. C. Pfefer, William W. Stenzel, and Byoung Doo Lee. "Safety Impact of the 65-mph Speed Limit: A Time Series Analysis (Abridgment)." Transportation Research Record, 1318 (1991), p. 32.
"...when traffic volume variations are taken into account, there is no strong evidence that there was an effect on accidents [in Illinois] associated with [the 65 mph law]. ... In fact, the incidence of car-truck accidents decreased after the change."

R. N. Smith. "Accidents Before and After the 65 MPH Speed Limit in California (Supplemental Report)." California Department of Transportation, Division of Traffic Operations, (1990 October).
"It is concluded that raising the speed limit to 65 mph on rural interstate routes did not increase fatal and injury accidents, when traffic volume changes and preexisting accident rate trends are accounted for."

Charles A. Lave. "Speeding, Coordination, and the 55 MPH Limit." The American Economic Review, 75.5 (1985 December), p. 1162.
"... there is no discernible effect of speed on the fatality rate. This conclusion is not contradicted by the observed drop in fatalities following the imposition of the 55 mph NMSL [National Mandated Speed Limit] in 1973, since speed variance fell that year."

Rev: 1998.09.29