Big interchange project near Allegiant Stadium grows in cost

The planned overhaul of the Tropicana Avenue-Interstate 15 interchange near Allegiant Stadium has seen two new features added and its price increased.

Originally pegged at up to $230 million, the project’s price tag has grown to $273 million, of which $243 million is tied to construction on the project, according to Tony Illia, Nevada Department of Transportation spokesman.

Part of the increase is tied to adding a $30 million project that was already in the works — repaving I-15 between Warm Springs Road and Hacienda Avenue — to the Tropicana overhaul. Illia said this will save the state money in the long run by not having to carry out the project separately at a later time.

“Keep in mind that the department was going to do the pavement preservation project whether it was a part of the interchange makeover or not,” Illia said. “Technically, we will be saving money and reducing traffic impacts by folding this work into the project. There is a significant savings by avoiding the creation of another separate project. It cuts down on department and management expenses as well as contractor mobilization fees, which are typically around 10 percent of the total contract cost.”

The other addition is upgrading the sewer lines under Tropicana within the project’s scope. The work is for the Clark County Water Reclamation District, which will pay for the project’s costs.

Planned to get underway in early 2022, the project marks the first major upgrade to the Tropicana-I-15 interchange since it was constructed in the 1960s.

“This is a location where traffic really starts to back up. The reason for that is we widened I-15 from the south to this point, but the Tropicana bridge is too short to allow any future widening,” NDOT Project Manager Lynnette Russell said at last week’s Clark County Commission meeting. “We need to make the bridge longer in order to continue widening to the north.”

Russell also noted the bridge as it stands is too low and has been struck by tractor-trailers several times over the years.

“For that reason, we need to make the bridge taller,” Russell said.

The project’s scope includes I-15 between Russell and Flamingo roads and Tropicana between Las Vegas Boulevard and Valley View Boulevard.

Tropicana over I-15 is deteriorating because of unanticipated volumes of traffic, so the capacity needs to be increased on the freeway ramps and the bridge over the interstate, Russell said.

Plans call for reconstructing the interchange, creating a diamond on-ramp and offramp configuration and a flyover at Tropicana.

Dean Martin Drive will be reconfigured to go underneath the Tropicana freeway ramps, removing a traffic signal at the intersection near the In-N-Out restaurant. Circular roads will be added to maintain access to the northwest and southwest quadrants.

“You don’t need a traffic model to recognize one of the things that contributes to the operational breakdown of the interchange is the current density of signals along Tropicana, in particular the signal at Dean Martin, which is very close to the signal for the southbound ramps,” Russell said. “To remedy this issue, this project will eliminate the signal at Dean Martin.”

Sidewalks on Tropicana over I-15 will be widened from 5 feet to 10 feet, and a new pedestrian walkway will be built from the north side of Tropicana down to Frank Sinatra Drive, opening a new pedestrian access point to T-Mobile.

High occupancy drop lanes are also planned to be added to and from Harmon Avenue, which would be located on the south side of the bridge.

With I-15 and Tropicana leading to the south end of the Strip, T-Mobile Arena and Allegiant Stadium, mitigation measures are in place to ensure traffic will be able to travel in and out of the area during construction.

“At no time will business access be completely closed off,” Russell said. “The department has been proactive in meeting with and working with stakeholders throughout the design development process. We will continue to work closely with stakeholders immediately adjacent to the project as well as business in the surrounding areas.”

As part of the project, 10 more active traffic management signs are planned to be installed on I-15 between Russell Road and the 215 Beltway, which will help with event traffic to Allegiant Stadium and T-Mobile Arena.

Five of the signs will be installed on both the north and southbound sides of I-15.

The dynamic traffic management signs can display real-time traffic information including lane closures, crashes and backups. They also can change the posted speed limit as needed to decrease the chance of crashes.

With the timeline calling for construction to take at least 26 months, the project’s earliest anticipated completion would be mid-2024. If Las Vegas is awarded the Super Bowl that year, as it’s rumored to be a possible site, construction would be occurring during the major event.

Commissioner Michael Naft aired concerns about the impact the project could have on an event the magnitude of the Super Bowl.

Jack Sjostrom of the CA Group that is assisting NDOT on the project, said it will ensure that no major closures or lane reductions are planned around any special event in the area.

“We will be working with the design builder to identify any future special events … to make sure there’s adequate capacity on I-15 to move travelers from California back and forth from home to the events, as well as locals,” he said.

Contact Mick Akers at makers@reviewjournal.com or 702-387-2920. Follow @mickakers on Twitter. Send questions and comments to roadwarrior@reviewjournal.com.