The early reports are in on the first year of Idaho’s increased 75 mph speed limit on interstate highways.
And even though the new limit allows drivers to travel 10 mph faster, most are going only about 3 mph faster. That is because they did not obey the old 65 mph limit.
It also appears the number of speed-related deaths are down.
The speed limit on Interstate 90 fluctuates six times in the relatively short 73 miles between Washington and Montana. And only one stretch - from the Rose Lake junction just east of Fourth of July Pass to Osburn - permits the maximum 75 mph.
According to Idaho Department of Transportation figures, more than half of the state’s drivers ignored the old 65 mph speed limit on interstate highways, choosing instead to drive at what they thought was a safe speed, about 72 mph.
When Congress lifted the federal 65 mph limit, Idaho and other expansive Western states considered raising the limit to 75. Overnight, the more lenient speed limit would turn the more than half lead-footed Idaho drivers into law-abiding motorists, the experts argued.
Opponents said a 75 mph speed limit would turn Idaho’s interstates into a German autobahn, with motorists traveling up to 90 mph.
But Transportation engineers predicted that would not happen. Most people drive at speeds at which they feel in control. Traveling at 80 mph or faster would not appeal to sensible drivers, they said.
A year later, it looks as if the experts were right.
The 85th percentile speed - the speed 85 percent of drivers travel at or below - after the new speed limit was enacted, was 75.9 mph. The 85th percentile speed for the same six-month period before the new speed limit, was 72.2.
“My initial reaction based on what we’ve seen nationally is that the impact of a 10 mph increase was that the average speed would go up 2 to 4 miles per hour,” state engineer Greg Laragan said.
Total fatalities are up in Idaho with 60 through April 18, compared with 48 during the same period a year ago, said Lt. Da’nny Bunderson, deputy Idaho State Police commander in eastern Idaho.
Prior to the study period, there were about 3.2 fatal Idaho accidents per 100 million vehicle miles either partly or completely caused by high speeds. That dropped to 2.3 deaths from May 1996 through October 1996, the Transportation Department said.
Laragan cautions against early conclusions.
Another negative to the new speed limit law, Bunderson said, is that many drivers are not slowing down after they leave an interstate to state highways not built for that speed.
Bunderson also said too many drivers are not slowing down when road or weather conditions warrant. He said the 75 mph speed limit is being strictly enforced.
, DataTimes MEMO: IDAHO HEADLINE: Most drivers in Idaho go only slightly faster
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