Even at lower speeds, the Idaho Transportation Department expects that motorists can make a daily northbound commute through the Wood River Valley faster once the state Highway 75 expansion project is finished.
In fact, according to the project's environmental impact statement, "peak hour driving time" should be 11 minutes faster for anyone driving the entire 27-mile highway stretch involved in the expansion. Peak-hour driving from Timmerman Junction south of Bellevue to Saddle Road in northern Ketchum now takes an average of 60 minutes. Once the highway project is completed, the drive should take only 49 minutes, ITD says.
ITD project engineer Mike Scott said average "peak hour driving time" estimates were extensively studied and calculated from northbound morning commute traffic.
According to the EIS, the 11 minutes will be saved at various intervals along the route, but the biggest time reduction will be realized from McKercher Boulevard in northern Hailey to Elkhorn Road south of Ketchum. Peak-hour driving time now for that stretch of road averages 21 minutes. The EIS estimates that once the expansion project is completed, the drive will take only 16 minutes.
Somewhat controversial in the valley is the fact that ITD, as stated in the EIS, intends to reduce the speed limit between Hailey and Hospital Drive south of Ketchum from 55 mph to 45 mph once the expansion project is completed. Scott said the new roadway design is for lower speeds, but that the speeds could be raised if an engineering study after the project is built shows that safety would not be compromised.
Even with the lower speed limit, Scott said, the improved drive times will be realized from traffic being spread out more evenly, allowing motorists to stay at more consistent speeds. Also, many traffic signals and intersections will be rebuilt to alleviate congestion and the need to reduce speed. For example, Scott said, some intersections will be rebuilt similar to the one at East Fork Road, where there are multiple lanes and drivers are given notice well in advance of coming signal changes.
He pointed out that the overall purposes of the expansion project are to better accommodate "peak-hour vehicle traffic" and to "increase transportation safety."
Scott acknowledged that non-peak-hour drive times, especially when traffic is light, may be a few minutes longer.
Once completed, the project will expand much of the highway to four lanes, with many areas having an additional center turn lane.
According to the EIS, speed limits will change in some areas and remain the same in others. The stretch of highway from Timmerman Junction to the Bellevue city limits will remain at 55 mph. The EIS also assumes that the cities of Bellevue, Hailey and Ketchum will retain city speed limits at 25 mph.
The speed limit from Bellevue to Hailey will be reduced from 55 mph to 45 mph, as will the limit from Hailey to Hospital Drive. The speed limit from Hospital Drive north to Serenade Lane will be 35 miles per hour.
When the entire project will be finished is still a big question.
"I need a big crystal ball for that one," Scott said. "I wouldn't even want to venture a guess based on how funding is these days. It's long term—that's the best way to say it."
The project is expected to cost about $250 million. ITD currently has $29 million in hand, which is enough to complete Phase 1, the 3.25-mile stretch of highway north of East Fork Road to the Big Wood River Bridge near St. Luke's Wood River Medical Center.
Construction on Phase 1 is scheduled to be started in 2013.
Terry Smith: firstname.lastname@example.org