We all see the speed-limit signs on the side of the road, and even roadside memorials, serving as reminders to drive safely and at the proper speed. There is good reason to heed their guidance, thereby reducing injury risk and fuel consumption. Speeding is a factor in about one-third of all fatal crashes and causes more than 1,000 American deaths per month. Beyond the human tragedy, the National Highway Traffic Safety Administration (NHTSA) estimates that speed-related crashes cost over $40 billion a year.
Speed limit laws date back to 1901 and have traditionally been the responsibility of the states, except for a period between 1974 and 1995 when the federal government stepped in to help regulate. Speed limits were then set to 55 mph, but as the oil shortage and fears of fuel availability faded, the numbers headed back up. In 1987, states were allowed to increase the limit on rural highways to 65 mph and in 1995, the National Highway System Destination Act repealed the maximum speed limit, allowing and all states were allowed to go back to determining their own limits on all roads. Currently, 33 states have limits of 70 mph or higher.
Research by the Insurance Institute for Highway Safety (IIHS) has shown that when the speed limit increases, people drive faster. In a recent study, the Institute looked at eight metropolitan areas and found that on urban interstates, travel speeds exceeded the limits. On those roads, speeds greater than 70 mph ranged from 1 to 38 percent in the eight areas. Speeds over 75 mph on all types of roads (suburban and rural) ranged from 6 to 49 percent. The reverse also happens. Four years after the 1995 repeal, Montana reinstated the 55 mph speed limit and travel speeds plunged. (Read the IIHS Q&A on speeding.)
How does speeding affect crash data?
Deaths on rural roads increased 25-30 percent in 1987 after the states increased the speed limits from 55 to 65 mph. In 1999, IIHS estimated a 15 percent increase in fatalities due to the 1995 repeal of the speed limit law. In 2007, speed was a factor in 26 percent of crashes with injuries.
Who is speeding?
A 2002 survey by the NHTSA found that three-quarters of drivers admit to speeding the previous month. Speeding is a problem for all drivers, but men are 50 percent more likely than women to drive over the posted limit. The biggest offenders are males under 30 years old. Incidentally, the proportion of deaths from speed-related crashes decreases with rising driver age.
Can technology help?
Radar detectors have been used for years to warn drivers to slow down before they were caught by police officers, but now many portable GPS devices use speed warnings to help monitor driving. Rather than warn that you may get caught speeding, some GPS navigators help drivers obey the law by displaying the posted speed limit and issuing a warning when you are over the limit at user-selectable intervals.
Speeding vs. fuel costs
Besides the risks of driving over the limit, speeding reduces fuel economy, as well. Our tests with a Toyota Camry found that when we increased the Camry's highway cruising speed from 55 mph to 65, the car's fuel economy dropped from 40 mpg to 35. Speeding up to 75 mph cost the car another 5 mpg.
The bottom line
We all know the statistics—speeding increases the risk of crashes, causes reduced fuel economy, and can get you a ticket. So, what can be done? Last summer, Senator John Warner of Virginia expressed interest in a return to a federally mandated speed limit to conserve fuel, but public and state support would be unlikely. Many states are putting money into speeding awareness campaigns or setting up speed cameras to help curb the problem.
What are your thoughts? Do you think the government should reinstitute a national speed limit in order to decrease fuel economy consumption and save lives? Are speed warnings via GPS or other technology useful? Would you support a return to the 55 mph limit? Please post your comments below.