It would also allow 80 mph zones in any areas that engineers decide are safe on I-15 from Brigham City to the Idaho border, on Interstate 84 from Tremonton to Idaho and on Interstate 80 from Nevada to the Tooele-Stansbury exit.
Sen. Margaret Dayton, R-Orem, suggested Monday also perhaps adding a just-rebuilt stretch of I-15 in Utah Country from Lehi to Spanish Fork, since most traffic there is already going that fast.
Dunnigan agreed that "the prevailing rate of speed does not match with the posted speed limit" there. "I think that's an area that could be looked at. I'm not sure it needs to be done in this legislation."
Sen. Karen Mayne, D-West Valley City, then suggested that the areas under consideration for higher speeds be broadened.
"I think every area should be looked at" on freeways statewide, she said.
Dunnigan said studies showed that before speed limits were raised in test areas, speeds averaged 82 mph. When the limit was raised to 80 mph, average speed rose by only 1 mph to 83 mph. He said the new limits seemed only to make legal what most drivers felt was the natural flow for those stretches.
Dunnigan said studies show no fatalities occurred in test areas, and accident rates stayed the same or decreased there.
He has also said he does not think more 80 mph zones would worsen urban air pollution because studies show newer cars pollute about the same between 55 mph and 80 mph although older card do and most areas under consideration for higher limits are also in rural areas.
Dunnigan said he could be open to amendments in his bill to add more 80 mph-eligible areas, or other legislation could add them later.
Sen. Kevin Van Tassell, R-Vernal, said he prefers to add only the areas proposed so far, and urged legislators move slowly and cautiously on expanding the higher-speed limits.
"When it was snowing over the weekend and we had a lot of accidents again, I wonder if we know how to drive when it's bad" weather, he said.
Utah and Texas currently are the only states that have any speed limits higher than 75 mph. Most Utah freeways in rural areas have 75 mph limits, while the limit is 65 mph in urban areas.