Adding lanes to I-15, upgrading interchanges and building the West Davis Highway.

That's what has to be done to avoid gridlock along a 20-mile stretch of I-15 between 600 North in Salt Lake City and 200 North in Kaysville, a study says.Planners from the Wasatch Front Regional Council presented the findings Friday to the Utah Transportation Commission.

The study emphasizes the significance of maintaining traffic flow within the south Davis County corridor served by I-15. "The existing and future economic vitality of the corridor depends to a large degree on the capability of

I-15 to effectively link the corridor with the rest of the Salt Lake-Ogden metropolitan area," the study said.

The worst area of traffic congestion along I-15 is between the I-215 and Parrish Lane interchanges, where stop-and-go traffic is common during rush hours. Also, the study said traffic often stalls on several interchange ramps, and lane changing between the closely spaced 500 South and 400 North ramps poses safety problems.

Most traffic accidents in the study area occur in segments from 2300 North to Beck Street and from I-215 to 2600 South as well as the 600 North, 2600 North and Parrish Lane interchanges.

According to the study, it can only get worse. Planners predict traffic in the next 20 years will grow by 35 percent near Kaysville and 100 percent near the Salt Lake County and Davis County line.

To prevent certain gridlock, the study offers short-term and long-term solutions.

In the next 10 years, state and local transportation officials should plan on adding one lane in each direction along I-15, between the I-215 and 2600 South interchanges and between the 500 South and 400 North interchanges. Several interchanges also need improvements.

Interchange improvements include extending on-ramps, upgrading off-ramps, relocating frontage roads and installing traffic signals where warranted, the study said.

Short-term costs for the highway improvements are estimated at $12.82 million.

Responding to the Utah Transit Authority, the study also recommends expanding bus service in Davis County at a cost of $1.6 million to put in place and $540,000 a year to operate.

In the long run, the study recommends spending $142.24 million on adding one lane in each direction of I-15 between 600 North in Salt Lake City and U.S.-89 in Farmington, construction of a West Davis Highway from I-215 to Farmington, upgrading several interchanges, and a new interchange at Glover's Lane in Farmington.

The Wasatch Front Regional Council staff is working with government leaders in Davis County to pin down the alignment of the West Davis Highway, then start purchasing land to preserve the right-of-way.

In addition to further expansion of bus service in the next 20 years, transit officials should also study the feasibility of a light-rail transit system or freeway lanes dedicated to buses in the next 20 years, the study said. Transit capital costs are estimated at $5 million and annual operating costs would be $3 million.

UTA officials didn't disagree with the study's conclusion that more transit service is needed in south Davis County. But UTA does wonder where the funding will come from. "It will be difficult to do under the current circumstances," UTA general manager John Inglish said.

The results of the study, sponsored by the Utah Department of Transportation and Utah Transit Authority, didn't surprise the commission.

UDOT planning director Clint

Topham said the study's recommendations are incorporated in UDOT's "needs assessment" document, which outlines billions of dollars in highway projects needed to accommodate future traffic growth.



Davis County's traffic flow

Short-term solutions


- Add lane in each direction of I-15, between I-215 and 2600 South.

- Improve interchanges at 600 North (Salt Lake); 900 West (Salt Lake); 2600 South (Woods Cross); 500 North (Bountiful); 500 West (Bountiful); Parrish Lane (Centerville); South Farmington; and Burke Lane (Farmington).

- Additional lane on I-15 between 500 South and 400 North.

- Extend three I-15 northbound lanes through Beck Street interchange.


- Increase frequency on routes 55 (Salt Lake-Weber State), 70 (Salt Lake-Ogden), and 72 (Golden Spike Express).

- Add new peak hour routes for East Layton/Fruit Heights Express to Salt Lake; Farmington/Centerville Express to Salt Lake; and West Bountiful to Salt Lake.

Long-term solutions


- Construct West Davis Highway from I-215 to Farmington. Alternatives for location are existing Redwood Road alignment or build new road just west of Redwood Road.

- Add one lane in each direction from 600 North in Salt Lake to U.S. 89 in Farmington.

- Upgrade interchanges at 600 North (Salt Lake); Beck Street;

I-215; 2600 South (Woods Cross); 500 South/400 North (Bountiful); Parrish Lane (Centerville); Burke Lane/U.S.-89 (Farmington).

- Build new interchange at Glover's Lane and close Farmington interchange.

- Close southbound off-ramp at Center Street in North S.L.


- Expand bus service.

- Construct additional park-and-ride lots.

- Study potential rail corridors and dedicated freeway bus lanes.