ST. GEORGE – More than a week ahead of schedule, the Interstate 15 – St. George Boulevard interchange will be switched over from a traditional diamond interchange to a diverging-diamond-interchange configuration beginning this Saturday. Crews will close St. George Boulevard between the freeway on- and off-ramps from Saturday at 11 p.m. until Tuesday at 6 a.m. in order to make the switch.
Originally, the new interchange was scheduled to be open before Black Friday on Nov. 29 to accommodate holiday shopping at area businesses. Now, Utah Department of Transportation is pleased to open the interchange more than a week ahead of schedule.
“It is important to UDOT and the City of St. George to make sure that the construction of this project doesn’t adversely affect area businesses,” UDOT Project Manager Kim Manwill said. “We want to make sure that the economy in the area stays strong throughout the project duration. I think, so far, we have met this goal.”
What is a diverging-diamond interchange, or DDI?
A DDI briefly swaps traffic to the opposite side of the road as it passes over the interstate, this allows left turns to be made on and off the freeway without the need for a signal. This provides more efficient signal operations, which significantly reduces delay; increases the capacity at the existing overpass by removing the need for turn lanes; increases the capacity of turning movements to and from the ramps; substantially reduces the number of conflict points, which improves safety; and improves pedestrian safety.
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Navigating the new St. George Boulevard Diverging Diamond Interchange
“There are several DDIs in operation in Utah and we are excited to have the first DDI in Southern Utah,” Manwill said. “This new interchange type will keep traffic flowing and allow for future growth in St. George.”
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Making the switch to a DDI will require the closure of St. George Boulevard between 1000 East and River Road. Right turns will still be permitted at each ramp. The northbound off-ramp is scheduled to close the nights of Saturday, from 11 p.m. to 8 a.m., and Sunday, from 10 p.m. to 6 a.m., but will remain open during the day. There will be no east-west access on St. George Boulevard across the bridge throughout the duration of the closures. Motorists should use 100 South as an alternate east-west route. St. George Police Department will be present to assist motorists and protect the work zone.
During the two-day closure, crews will place new signal poles, excavate existing concrete islands, install new traffic signs, install sidewalk barrier and curbing, pave the bridge, and paint new striping. When the interchange re-opens Tuesday morning, traffic will be in the new DDI configuration. Minor construction activities will continue in the project corridor and on I-15 through December 2013.
Road closure and alternate route details
- St. George Boulevard Bridge, between 1000 East and River Road | Saturday at 11 p.m. until Tuesday at 6 a.m.
- Motorists should use 100 South as an alternate east-west route.
- St. George Boulevard northbound off-ramp closure | Saturday from 11 p.m. to 8 a.m. | Sunday from 10 p.m. to 6 a.m.
- Motorists who want to exit the northbound off-ramp should use Dixie Drive (Exit 5) or Bluff Street (Exit 6) as alternate exits.
Road restriction details
- I-15-St. George Boulevard on- and off-ramps | Saturday at 11 p.m. until Tuesday at 6 a.m.
- Only right-turn movements will be allowed.
Resources and contact information
- Contact: Project Hotline – 435-216-9313 | Project email
- Website: Visit UDOT for more information about the project, construction activities, and road closures.
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