BOISE — Some stretches of freeway in Idaho could see speed limits rise to 80 mph, under legislation that won final passage in the Idaho House on Tuesday and headed to the governor’s desk.

The House was closely divided, approving the measure on a 34-31 vote, with opponents citing safety concerns.

Backers said the Idaho Transportation Department (ITD) would only up the top speeds on sections where it determines, after engineering and traffic studies, that it would be in the public interest. Attention is aimed squarely at the southern end of the state, where Interstate 84 across the Utah state line already is at 80 mph, while Idaho remains at 75.

Rep. Marc Gibbs, R-Grace, the bill’s House sponsor, said, “I think it can safely be done in Idaho.”

Utah did a three-year experiment with 80 mph top speeds and found that accident rates didn’t rise with the higher limit, in part because drivers on the selected stretches of freeway mostly went no faster than they had before.

The bill, SB 1284a, also would allow Idaho to raise top speeds from 65 mph to 70 mph on selected stretches of state highway, under the same conditions. If Gov. Butch Otter signs the bill into law, it would take effect July 1; it would then be up to the ITD to decide when, or if, any speed limits would rise.

Utah is currently the only state with an 80 mph top speed limit, but Texas is at 85 mph.