UDOT unveils details on new $1.6B widening of I-15 through SLC

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It’s not sure how many homes and businesses will be demolished.

And the exact cost is still uncertain (though early estimates put it around $1.6 billion).

But the Utah Department of Transportation is planning to widen Interstate 15 from Salt Lake City to Farmington.

The project comes on the heels of UDOT widening I-80 in Sugar House, I-215 in Millcreek, I-15 in Salt Lake and Utah counties, US-89 in Davis County and the Mountain View Corridor in Salt Lake County. The state is also building a new highway in Davis County called the West Davis Corridor.

Like transit, these projects are subsidized by the state’s general fund because the state gas tax hasn’t kept up with the pace of construction and high cost of highway maintenance, and vehicle registration fees aren’t high enough to close the gap. Yet the highway-building, which will lead people to drive more, creating more local and global air pollution, continues.

UDOT on Monday began its latest round of public outreach on its proposals for adding lanes and interchanges to I-15 and reconfiguring streets and roads near the interstate.

This round of highway widening spans from 400 South in Downtown Salt Lake City to Farmington. It has been narrowed down to two options that UDOT is accepting feedback on at a series of open houses and online. (The next open house is Tuesday evening at Rose Park Elementary School from 5 p.m. to 7 p.m. Food and activities for kids are offered.)

One option would include six lanes in each direction, including an auxiliary lane on the sides, plus a single high-occupancy vehicle lane in the middle. Add four more lanes for shoulder space and I-15 would be 18 car-lanes wide under option A.

Option B would also have six lanes in each direction, plus two shoulders. Between both sides of the interstate, UDOT would create two high-occupancy vehicle lanes (plus two shoulders), for a total of 20 lanes across. The set of HOV lanes would be reversed during peak hours, open to southbound motorists in the morning and northbound at night.

When counting auxiliary lanes, the interstate would be nearly two dozen car-lanes wide including shoulders and its width would be nearly the same as a U.S. football field. Building Salt Lake counts shoulder space in lane counts because it is land from the public realm that will indefinitely be unusable for anything but cars.

UDOT officials said they don’t yet know the number of homes and businesses that will be demolished with a wider interstate, though the answer will be revealed in coming months after more engineering work that might account for public comments.

There are streets in Salt Lake City’s Guadalupe and Fairpark neighborhoods that are very near the interstate. 700 West is also within the area of potential impact.

For Rose Park and Marmalade, the 600 North overpass would be widened to eight lanes at its peak from its current six. A painted bike lane is striped across for anyone daring enough to ride on it. Option B also includes a shared use path over the overpass.

The plan includes a number of painted bike lanes that are wedged against the curb next to multiple lanes of high-speed traffic on approach or departure from the interstate.

For both options A and B, UDOT would create an underpass at 500 North that’s open to people walking or riding bikes. That route dead-ends just east of the interstate when it hits the railroad tracks, so users would have to divert to 400 North or 300 North to continue east.

UDOT also plans to create an underpass at 400 North that’s open to motorists and people walking. The east side of Beck Street would get a path that ends in North Salt Lake.

Beck would also become connected to I-15 at a new interchange added at 2100 North in Salt Lake City, which state officials say might divert heavy truck traffic from the gravel companies and refineries so they avoid Marmalade and Capitol Hill.

The Legislature has largely written UDOT blank checks for highway expansion.

“The Legislature is very fiscally responsible in the fact that they program the amount of infrastructure needs appropriately,” said Tiffany Pocock, the project manager. “This has already been appropriated so [it] will not increase your taxes today.”

 “You heard it here first, your taxes will not be increased for this project,” added Dan Adams, a consultant working with UDOT.

But there are more fiscally responsible options for the state to consider and the public to request. For instance, not expanding the interstate.

UDOT says this option would lead to pre-pandemic travel times increasing from about 20 minutes to about an hour without highway expansion.

It’s worth noting that traffic modeling used to project how many people will be driving in three decades is routinely overinflated. In the early 1990s, when the state was working to justify turning US-89 through Davis County into a freeway, the state predicted crippling traffic by 2015.

In some cases, the state’s projections were off by 30 percent, meaning nearly 1 in 3 drivers the state said would be using US-89 in the future never came. The state is wrapping up that project now.

Another consideration would be to increase the requirement for driving a car in the high-occupancy vehicle lane, from at least two people to three.

The Legislature made this change in Senate Bill 2001 in 2019, when it passed a massive omnibus bill that also included a tax hike on groceries. Voters were on their way to passing a ballot measure repealing that law when the Legislature did it themselves, so the high-occupancy vehicle changes went with the rest of it.

Utah could instead spend a fraction of the cost by implementing the Rio Grande Plan, a citizen-led plan to open up developable space on the west side of Downtown Salt Lake City. That plan is expected to generate billions of dollars in ongoing economic impact every year, but the state so far has ignored it.

Utah could focus on more quickly building out its transit network.

For its part, the Utah Department of Transportation and gondolas is pointing to regional transportation planning from the Wasatch Front Regional Council as justification for ongoing highway expansion.

Sweet Streets, a Salt Lake City-based group that includes leaders from Building Salt Lake, is organizing an effort to oppose the proposal.

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Posted by Taylor Anderson

Taylor Anderson grew up near Chicago and made his way West to study journalism at the University of Montana. He's been a staff writer for the Chicago Tribune, Bend Bulletin and Salt Lake Tribune. A move from Portland, Oregon, to Salt Lake City opened his eyes to the importance of good urban design for building strong neighborhoods. He lives on the border of the Liberty Wells and Ballpark neighborhoods.