NEW YORK (Reuters Health) - Higher speed limits led to about 12,500 more deaths on US roads between 1995 and 2005, a new study in the American Journal of Public Health shows.
Earlier studies had suggested that any effects of an act of Congress that eliminated all federal controls on speed limits would be temporary. The findings debunk those claims, Dr. Lee S. Friedman of the University of Illinois in Chicago, one of the study's authors, told Reuters Health.
To date, Friedman and his team note in their report, most studies of the effects of speed limit changes on highway fatalities and injuries have looked at only a couple of years' worth of data, in only a few states. In their analysis, the researchers looked at traffic fatalities in every US state except Massachusetts and Hawaii over the decade after the change in Federal law.
The National Maximum Speed Law, passed in 1974, put a 55 mph speed limit on all interstate roads. The law was intended to cut fuel consumption in the wake of the 1973 oil embargo, but it also led to a 16.4% reduction in car crash mortality from 1973 to 1974, Friedman and his colleagues note in their report.
In 1987, Congress passed the Surface Transportation and Uniform Relocation Assistance Act allowing states to lift the speed limit on rural interstates to 65 mph, which 41 states did. In 1995, Congress passed the National Highway Designation Act, which wiped out all federal speed limits.
Overall, Friedman and his team found that increased speed limits led to a 3.2% jump in road deaths. On rural interstates, car crash deaths increased 9.1%, while the increase for urban interstates was 4%.
The biggest increases in deaths due to increased speed limits were seen in states that had 55 mph speed limits before 1995 and raised them to 65 afterwards.
In states that kept the same speed limits, the number of deaths and injuries in fatal car crashes actually declined.
Overall, Friedman and his colleagues estimate that the federal law change led to 12,545 more deaths on US highways, and 36,583 more injuries in fatal crashes.
Bringing back a federal speed limit could not only save lives, Friedman noted; it could also reduce carbon emissions and dependence on foreign oil. The Surface Transportation and Uniform Relocation Assistance Act is coming up for renewal this November, which could offer an opportunity to put a new federal speed limit in place, he said.
More speed cameras could also help make roads safer, Friedman added. These are automated systems that take photos of speeders and their license plates, and then send the offender a ticket in the mail.
"You don't have the fun of having a police officer pull you over and take your license," Friedman said. Nevertheless, he added, "these systems are very effective for reducing and controlling systematic speeding."
SOURCE: American Journal of Public Health, September 2009.