Chicago, Illinois – The repeal of the U.S. federal speed control law in 1995 has resulted in an increase in road fatalities and injuries, according to researchers at the University of Illinois at Chicago School of Public Health.

The research, published in the September issue of the American Journal of Public Health, is the first long-term study to evaluate the impact of repealing the National Maximum Speed Law on road fatalities and injuries in fatal crashes between 1995 and 2005.

The law restricted the maximum speed limit to 55 mph (88.5 km/h) on all interstate roads in the U.S. It was initiated in 1974 in response to the oil embargo and had an immediate impact.

“During the first year, there was a drop of almost 17 per cent in fatalities after the speed laws were reduced to 55 miles per hour,” said Lee Friedman, lead author of the study.

The law was modified in 1987 and allowed states to raise the legal speed limits to 65 mph (104.6 km/h) on some interstates. In 1995, the federally-mandated 55 mph speed law was revoked, allowing states to set their own speed laws.

“The primary finding of our study was that over the ten-year period following the repeal of the National Maximum Speed Law, there were approximately 12,500 deaths due to the increased speed limits across the U.S.,” Friedman said.

The researchers used a mixed-regression model, taking into account when the speed limits changed in each state and such factors as car volume density, population density, variations in fleet sizes, types of vehicles on the road, vehicle age, and driver characteristics. Friedman said the primary flaw of previous studies is that they have only focused on selected states or regions, or have used a simple analysis to look at before-versus-after implementation of the law during a very short period of time.

The researchers suggest that policy makers reevaluate national policy on speed and road safety, and consider reduced speed limits and improved enforcement with speed camera networks. Such programs have been implemented in England, France and Australia and have shown immediate reductions in motor vehicle crash fatalities, Friedman said.


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