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New digital speed-limit signs will aid safety, traffic flow in I-84 work zone

CALDWELL - Beginning this week, ITD will deploy variable speed limits within the Interstate 84 construction zone in Canyon County in order to enhance safety for workers and travelers while maintaining good mobility until the project is complete.

Currently, speeds in the work zone are often reduced to 55 MPH or 45 MPH depending on construction activities. The variable speed limit signs posted to inform drivers about every mile in each direction will allow for responsive adjustment to speed limits displayed, in coordination with ITD and ISP, as activities within the work zone allow. When construction crews are not in the work zone or when safety barricades are in place, the speed limits may be raised to 65 mph. This further promotes mobility without sacrificing safety on the Interstate.

To establish the changeable speed limits, ITD will install numerous variable speed limit signs. Upon approval, crews can change the speed limit on these digital signs to actively manage conditions in the work zone. A flashing beacon will notify drivers in advance when speed limits are reduced from 65 mph.


“This project is complex and requires several phases of work,” said ITD Design Construction Engineer Shawna King. “There are numerous crews completing specialized work and the number and location of crews will vary day to day. Implementing the variable speed limits will allow us to keep crews and motorists safe while work is being done, then bring speeds back to normal when it is safe to do so.”

The work on I-84 between Franklin Road (Exit 29) and Karcher Road (Exit 33) will construct an additional third travel lane in each direction. Traffic is currently diverted to the outside lanes while crews construct the inside portion of the future roadway. When that phase of work is complete, traffic will be diverted onto the newly-constructed inside lanes and work will begin on constructing the outside lanes. Crews will also replace numerous bridge structures along the five-mile corridor.

“This technology will allow us to keep traffic moving as efficiently as possible along this key corridor,” said King. “Variable speed limits have a track record of enhancing safety in active work zones.”

Variable speeds have been successfully implemented in many other states, including Washington and Utah. Research shows the system tends to improve driver compliance with posted speed limits. This reduces crashes and improves safety for road crews and the motoring public.

ITD has committed to keeping delay impacts to the traveling public on this corridor to a minimum. This has included restricting major work to evening hours and keeping the existing number of lanes as two in each direction open during peak times whenever possible. The department believes implementing variable speed limits will further enhance safety and mobility of the corridor while completing this critically-needed congestion relief project.

The signs will be removed when construction is complete in summer 2023.

Details about I-84 construction are available at https://itdprojects.org/franklinroadtokarcher/ or by texting 84CORRIDOR to 1-866-ITD-84CC.