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Speed Limit Laws

Congress repealed national maximum speed limit laws in 1995. As of May 2005, 32 states raised speed limits to 70 mph or higher on some portion of their roadway systems, with legislation pending in a few others. Table 1 provides state rural and urban interstate speed limits.

Speed studies and impact on crashes

The average speed of drivers in the US is on the increase and most traffic safety researchers agree that raising speed limits is harmful.

Most motorists speed occasionally, straying a few miles per hour over the posted limit. Then there are the more serious violators, who substantially exceed speed limits and maintain speeds that are way out of sync with nearby motorists.

In 2005, Insurance Institute for Highway Safety (IIHS) researchers measured speeds at 13 locations on northern Virginia roads, identifying vehicles going at least 15 mph faster than posted limits and at least 5 mph faster than 3 of 4 surrounding vehicles. These parameters helped to ensure that the identified motorists weren’t inadvertent or occasional speeders.

Researchers found 5% of drivers exceeding the limits by 15 mph or more. Three percent also were going faster than nearby cars. These proportions aren’t large, but they translate into millions of problem speeders on US roads every day.

Analysis of photos of motorists in the group of problem speeders, snapped as they went by photoradar units, plus information obtained from authorities revealed characteristics of these drivers. They were more likely to be men younger than 30 and to drive newer vehicles and SUVs, compared with motorists who stayed within 5 mph of posted speed limits. As a group, the problem speeders averaged 60% more crashes per year and had twice as many violations on their records. For more information, download “Status Report, Vol. 40, No. 9, November 19, 2005” at http://www.iihs.org/sr/2005.html.

A study released in November 2003 by the Insurance Institute for Highway Safety shows that in the six states studied where rural interstate speed limits were raised, more than two-thirds of the vehicles on these roads were going 70 mph or faster. The states studied were CO, GA, CA, MA, MD and NM. The study also found that higher travel speeds translated into nearly 1,900 more deaths in 22 states between 1996–99.

Another component of the IIHS report includes highlights from a study by the Land Transport Safety Authority of New Zealand. The New Zealand study examined the number of deaths per million vehicle miles driven in 22 US states that immediately raised their limits to 70 or 75 mph after the repeal of federal speed limits. Trends from those states were compared with 12 states that kept their limits at 65. The study found states with increased speed limits to 75 mph had 38% more deaths per million vehicle miles than expected for an estimated 780 deaths. States with speed limits raised to 70 mph experienced a 35% increase, resulting in 1,100 more deaths.

Safer cars and highways may serve to encourage higher speeds, but no study to date has determined that driving faster than posted speed limits or prevailing road conditions is safer than driving at moderate speeds.

Ohio speed limit legislation and five-year crash statistics

In 1996, the Ohio General Assembly approved legislation allowing the Ohio Department of Transportation to raise speed limits to 65 mph on designated urban interstates and rural highways for passenger vehicles and commercial buses. Previous state law set the speed limits at 55 mph on urban interstates and rural highways, and 65 on rural interstates. (See Table 2 for history of Ohio’s speed limit laws.)

Ohio is one of 11 states with differing speed limits on cars and heavy trucks (see Table 1). In September 2004 the Ohio Turnpike Commission’s higher speed limits for trucks went into effect. Speed limits for commercial trucks using the Ohio Turnpike increased 55 mph to 65 mph.  It was part of the commission’s plan to get more trucks to use the Ohio Turnpike. Truck traffic began spilling over to smaller roads after an 82% toll increase took full effect in 1999.

According to a safety and traffic report on the change in Ohio Turnpike speed limits for trucks, (www.statepatrol.ohio.gov/publications/2004-05 Turnpike Report.pdf) issued in October 2005, comparing speed and crash statistics for September 8, 2004 to September 7, 2005 when truck speeds were first increased to 65 mph compared to the averages for same period for the three previous years, there was a:

• 24% increase in total crashes since the speed limit change (524 crashes)
• 40% increase in commercial crashes (230 crashes)
• 123% increase in at-fault speed-related commercial crashes during “dry” road conditions (38 commercial crashes)
• 100% increase in commercial fatalities during “dry” road conditions (3 fatal crashes)
• 49% increase in commercial injury crashes during “dry” road conditions (28 commercial injury crashes)
• 17% increase in commercial volume (1.5 million vehicles)
• 10% decrease in heavy commercial vehicles [over 80,000 lbs.] on the turnpike  (24,374 heavy commercial vehicles)
• 21% increase in commercial vehicle miles traveled (169 million VMT)
• 7% increase in average commercial speed to 66 mph (4 mph increase)
• 46% increase in total crashes on the turnpike between mile posts 140 and 174 (240 crashes)

In Ohio, fatalities declined following the passage of the 55 mph speed limit law in 1974, the oil crisis era. Fatalities in the Buckeye state have been under the 2,000 mark since then with the exception of three years, 1978–1980. Worth noting is the fact that there was a 6% increase in Ohio fatalities in 1987, the year after Congress raised speed limits to 65 mph on rural interstates.

Trends in Ohio’s fatal crashes, according to the Ohio Department of Public Safety (ODPS), show they have remained relatively stable over the past five years, with 2006 reporting the least in the most recent five-year period. There were 1,142 fatal crashes in 2006 and 1,229 fatal crashes in 2005, compared to 1,162 fatal crashes in 2004; 1,168 fatal crashes in 2003 and 1,284 fatal crashes in 2002. Injury crashes have been on the decline during the same five-year period, down over 13% between 2002-06. ODPS figures show 83,297 injury crashes in 2006, 88,641 injury crashes in 2005, 94,058 injury crashes in 2004, 94,970 in 2003 and 95,374 injury crashes in 2002.

Table 3 provides 2004–2006 figures regarding speed and crashes in Ohio.

According to the Ohio State Patrol, driver inattention and drivers who were fatigued or tired caused more than 11,600 crashes in Ohio in 2006. (WCMH TV 4-Columbus,11/6/07)

¹ Effective 06/25/07, the speed limit may be increased to 70 mph on specific segments of highway upon the basis of an engineering and traffic investigation. On 07/10/07, highway officials increased the speed from 65 mph to 70 mph on Interstate 75 south of US 42, Interstate 71 west to the split to Louisville, and portions of Boone Carroll, Gallatin, and Grant Counties.
² In sections of I-10 and I-20 in rural West Texas, the speed limit for passenger cars and light trucks is 80 mph. For large trucks, it is 70 in the daytime, 65 at night.
³ Effective 07/01/06, the posted limit on I-85 may be as high as 70 mph
NA = Not applicable
Source: Insurance Institute for Highway Safety, June 2007
http://www.iihs.org/laws/speedlimits.aspx

Source: Excerpts from Ohio Historical Society

Source: Ohio Department of Public Safety, Ohio Traffic Crash Facts, 2004–2006 editions