Bangerter Highway Expansion Improves Mobility in Western Salt Lake Valley
Southwest of Salt Lake City, the communities of Kearns, Taylorsville, West and South Jordan are home to around 250,000 people, making it a major population center in the Salt Lake Valley. The communities are also gateways to expected development farther west in Herriman and Eagle Mountain.
Other than growth, the thing these communities have in common is a heavy reliance on the Bangerter Highway. The roughly 25-mile-long, north-south road runs parallel to Interstate 15 to the east and stretches from Salt Lake International Airport on the north end to an intersection with I-15 on the south.
Adan Carrillo, a community relations spokesman for the Utah Dept. of Transportation, says studies on improving traffic flow on the highway had been under way since 2005.
"We are always looking for ways to improve mobility and safety, and Bangerter Highway has become increasingly important to people in that part of the valley, and for expected future growth," he says.
The studies pointed to several problem areas along the highway. They were bid as separate projects, but all were corrected using innovative approaches. Carrillo says the department's engineering team hopes to improve mobility on Bangerter and several of its heavily congested crossroads—5400, 6200, 7000 and 7800 South—with two solutions that are new to the state: continuous flow intersections, or CFIs, and signalized flex-lanes.
North-South Flow
UDOT's studies on how to increase mobility on 6200, 7000 and 7800 South, near the popular Jordan Landing Shopping Center, pointed to the increased use of CFIs, says UDOT engineer Matt Zundell. A CFI takes the left-turn lanes from two opposing streets and moves them several hundred feet down the road. It creates two dedicated left-turn lanes and allows traffic to flow through an intersection longer without the conflict of cars waiting in the intersection to turn left.
"We did our first CFI in 2005-06, further north on Bangerter at 3500 South, and we had success with that," Zundell says. "We determined that using CFIs was the best way to relieve the backups at 6200 and 7000. It would give us more green (light) time for east-west movement. We also knew we wanted a grade-separated interchange on 7800. That is one of the busiest intersections in the state."
Draper, Utah-based Ralph L. Wadsworth design-builders was awarded the $49-million contract and began work in early 2011. Work on the CFIs at 6200 and 7000 South was carried out almost simultaneously and was nearly complete before crews began moving earth and preparing to build the grade-separated structure at 7800 South.
In addition to the CFI at 7000, crews extended the pedestrian overpass to access the Jordan Landing Shopping Center. A similar pedestrian overpass was replaced just south of 7800 to allow access to neighborhoods and a school on the east side of the intersection. The pedestrian bridge at 7800 was saved and re-used at a nearby project on Utah-111.
Construction of the 7800 South overpass and intersection was the most complex part of the project, says Brandon Squires, project manager for Ralph L. Wadsworth. "We had a school right there next to us. We had a moratorium on lane closures around the holiday shopping season," Squires says. "But the biggest thing was an aqueduct that runs along that part of 7800 South. It supplies more than half of the water for the valley. If something happened to that, it would be catastrophic."
The 78-in. pipe, managed by the Jordan Valley Water Conservancy District for the U.S. Bureau of Reclamation, handles around 20 million gallons of water a day. Squires says the design-build team worked to ease the fears of water managers by performing some reinforcing work on the pipe before beginning major construction of the intersection and the overpass.
"The pipe was in better shape than the managers had thought it would be when we got it uncovered," says Squires. "It's steel with a concrete-mortar lining that has been there since the late '60s or early '70s."
In November, the time of lowest water demand, the line was drained. "We installed 72 rubber gasket seals along about 1,000 feet of the pipe," Squires adds. "The seals at the joints allow the pipe to move a little without leaking. We had to get that done before we got started on any work at the intersection."
Other utilities, including natural gas and communications lines, were also relocated during construction. A temporary signaled "through U-turn" several hundred feet north and south of the 7800 South intersection was used to allow traffic to turn east or west off Bangerter during construction of the new intersection.
Now complete, the overpass allows six lanes of traffic (three each north and south) to pass over the 7800 South intersection on Bangerter. Traffic turning on or off the highway will use separate lanes similar to freeway ramps.
Carrillo says that in the coming years, the department will repeat the use of overpasses and CFIs at all of the intersections south of 7800. Eventually, north-south traffic will be able to move without stopping until the highway's intersection with I-15.
Opening a Clogged Arterial
Beginning at Redwood Road in the east and extending west across Bangerter, 5400 South runs east-west through the towns of Taylorsville and Kearns.
"Fifty-four-hundred South is one of the arterials that is highly utilized. Whether you want to go to Kearns, West Valley or West Jordan, there are a lot of people who use that road," says Carrillo.
Increasing capacity on 5400 South involves two strategies, Carrillo says, outright widening of the roadway from Redwood Road west and something altogether new to the Beehive State: signalized flex-lanes.
Because widening 5400 South from Redwood Road was not an option, engineers from UDOT and consulting firm Stanley Consultants, Salt Lake City, created flex-lanes—a system to utilize the existing lanes more efficiently during peak-use hours.
A series of 17 signal gantries was installed along a 2.1-mile, east-west section of the road. Each traffic lane has a signal indicating when it is open or closed or operating as a turning lane. A red x or green arrow will indicate whether traffic is permitted in a specific lane.
In the morning, during heavy traffic going east, more lanes will be turned into eastbound lanes, with the opposite occurring in the evening with heavier traffic westbound.
Vance Hanson, a project manager with Stanley Consultants, says the team looked at similar projects in British Columbia and Arizona, but the final design is unique to 5400 South.
"Nothing we were doing here was off-the-shelf," Hanson says.
The roadway proceeds up a grade from Redwood Road, so Hanson says engineers had to decide on the optimal placement of the gantries.
"We decided drivers should be able to see at least three lights ahead of them at all times," he says. "That should be far enough in advance so everyone would know what they were doing."
Hanson says the largest challenge of the project has been getting equipment to interface with existing systems at the UDOT Traffic Control center, where they will be monitored and controlled. The system is in its final phase of testing and is expected to begin operating before October.
West of Bangerter to 4800 West, 5400 South is being widened to seven lanes from five. The project involved acquiring property along the south side of the road, relocating residents and demolishing 38 homes.
Currently, contractors are placing new utility lines. Four new traffic signals will be installed as well as new warning lights at the fire station located along the road. Sidewalks will be widened and a sound barrier wall erected along the south side. The widening project is expected to be completed this fall.
PROJECT TEAMs Bangerter 6200, 7000 and 7800 South Owner: Utah Dept. of Transportation, Salt Lake City General Contractor: Ralph L. Wadsworth. Draper, Utah Civil/Earthwork: Hadco Construction, Lehi, Utah Design Engineer: Michael Baker Jr. Inc., Salt Lake City Utility engineers: Sorensen Cos. Inc., Syracuse, Utah 5400 South Redwood to Bangerter Owner: Utah Dept. of Transportation General Contractor: Geneva Rock, Murray, Utah Engineers: Stanley Consultants and AECOM, Salt Lake City 5400 South Bangerter to 4800 West Owner: Utah Dept. of Transportation General Contractor: Kilgore Construction, Magna, Utah
