On the outskirts of downtown Las Vegas, I-515 makes a big curve to the west, as seen in the photo above. This section of I-515 is known as the Charleston Curve and experiences high levels of traffic. Notably, it has been the site of an elevated number of accidents – four times higher that statewide averages, so the goal of the I-515/Charleston Interchange Project was to significantly reduce a hazardous traffic environment and reduce collisions.

In addition to working to remedy traffic and safety issues, air quality was also addressed in the project. The problem: Air quality becomes unhealthy when traffic backs up in the Las Vegas basin. In 2022, the annual average daily traffic (AADT) on Charleston Boulevard was 76,500, and on I-515, the AADT was 133,000. NDOT projects the 2040 AADT will reach 83,000 on Charleston Boulevard east of the interchange and 37,000 west of the interchange. Keeping traffic moving at a steady pace will significantly help to alleviate the carbon dioxide emissions.

The addition of an auxiliary lane and the widening of the Charleston Boulevard on-ramp required structural expansion to support the new lanes.

To resolve the issues of the Charleston Curve, NDOT initiated the I-515/Charleston Interchange Project. Some features of the project include:

  • Widening and reconstructing Charleston Boulevard from Honolulu Street to Sacramento Drive;
  • Increasing the number and length of turn lanes from Charleston Boulevard to I-515 ramps;
  • Constructing new traffic signals at ramp terminals and adjacent local road intersections;
  • Installing new LED street lighting on Charleston Boulevard and high-mast lighting on I-515;
  • Adding one auxiliary lane in each direction on I-515 from Charleston Boulevard to Eastern Avenue;
  • Widening I-515/Charleston Boulevard interchange ramps;
  • Widening the I-515/Eastern Avenue interchange northbound off-ramp;
  • Reconstructing the existing sound wall along northbound I-515; and
  • Adding a new sound wall on Charleston Boulevard.

NDOT awarded the $75-million project to Granite under a Construction Manager-at-Risk (CMAR) contract. In this Alternate Delivery Method, the owner contracts a construction manager to handle a project during the design phase and to oversee it until project completion. Granite was selected during preconstruction in 2017.

The Granite team at work preparing the grade for a new, widened off-ramp.

“I think NDOT chose the CMAR method to get a handle on the risks and control the costs,” said Pablo Chavarria, Project Manager with Granite Construction. FHWA provided 95% of the financing, and the State of Nevada provided the remaining 5%.

New structural support beams are lowered into place in the expansion of I-515.

Chavarria reported that 12,105 square yards of 11-inch Portland Cement Concrete Pavement (PCCP) went into the paving of the two auxiliary lanes and the widening of the interchange ramps. Additionally, 783 square yards of PCCP went into repairs of deteriorating existing pavement. All of the PCCP was performed using a Bunyan Roller Screed.

Charleston Boulevard is temporarily closed as new lanes are constructed on I-515.

Substantial completion for this project’s construction 460-day phase was reached last year on July 30, 2024.

Project Partners/Personnel

  • Owner:  Nevada Department of Transportation
  • General Contractor:  Granite Construction, Inc., Watsonville, California; Pablo Chavarria, Project Manager
  • Construction Manager:  AECOM/Stantec augmenting NDOT
  • Crew 915:  Susan Doucet, NDOT Assistant Resident Engineer; Tony Colagiovanni, Stantec Assistant Resident Engineer
  • Designer:  CA Group, Las Vegas, Nevada

Big thanks and a tip of the hard hat goes out to Granite Construction Project Manager Pablo Chavarria for all of his help with this story, along with Granite MarCom Manager Mark Phillips for the completion photos