Critical to the economic vitality of the western United States, the I-15 Corridor moves people to and from major trade gateways, tourist destinations, and population centers via:

Highway Travel

I-15 is a major transcontinental north-south highway in the western United States that extends more than 1,470 miles through the states of California, Nevada, Arizona, Utah, Idaho, and Montana. It is the principal artery linking coastal ports to inland population centers and connects with the nation’s three coast-to-coast east-west highways: I-10, I-80, and I-90 in addition to other east-west interstates including I-40, I-70, I-84, and I-86.

Currently, the primary obstacle for seamless movement on I-15 is congestion, which is casued by commute traffic, safety incidents, emergency conditions, natural disasters, and numerous other factors. The map below shows annual average daily traffic (AADT) volumes along I-15, paired with future traffic volumes, if no improvements are made. Green lines represent free flowing traffic, whereas red lines represent congestion. Even with planned improvements in place, congestion delay during peak times on I-15 between Southern California and Las Vegas is projected to grow from 3.19 hours per vehicle in 2012 to 7.03 hours in 2022.

Map of average daily traffic flows in project area.


Passenger Rail

Demand for passenger rail is expected to grow as highway and aviation systems reach their capacities. In particular, California has one of the busiest air markets and some of the most congested highways in the nation, making it a prime candidate for high-speed rail. Various passenger rail systems operate within the metropolitan regions served by I-15; however, no system currently connects the regions.

The Southwest Multi-State Rail Planning Study, led by Federal Railroad Administration (FRA) was completed in 2014 and included the states of Arizona, California, and Nevada. Conceptual planning analysis performed in the study indicates there are several multi-state corridors in the Southwest that could address increasing constraints on the transportation network and thus warrant further study in advance of possible new rail investments. The link between San Diego and Las Vegas through the Inland Empire is considered a high-priority route.

The southwest network could provide rail access to more than 92% of all Californians, Nevadans, and Arizonans.
The southwest network could alleviate future demand for the highway system equivalent to: 2 lanes on I-5 from Los Angeles to San Francisco or 6 billion vehicle miles traveled per year by 2050.

Map of rail corridors being considered in the project area.


Local Transit

Building supportive local transit systems to I-15 has been tremendously successful in removing short distance trips from the highway, both providing an alternative transportation option for local residents and freeing up capacity on the interstate, thereby providing additional benefits such as reduced greenhouse gases, less congestion, and improved safety.

Public transportation saves fuel, reduces congestion
Public transportation has a proven record of reducing congestion.
In 2011, U.S. public transportation use saved 865 million hours in travel time and 450 million gallons of fuel in 498 urban areas.
Without public transportation, congestion costs in 2011 would have risen by nearly $21 billion – or 18% - in 498 urban areas.
Public transportation reduces carbon footprint
Public transportation use in the United States reduces our nation’s carbon emissions by 37 million metric tons annually.
A single commuter switching their commute to public transportation can reduce a household’s carbon emissions by 10 percent, and up to 30 percent if a second car is eliminated.
Households near public transit drive an average of 4,400 fewer miles than households with no access to public transit.



Airports within the study area serve as major national and international gateways for leisure and business activities as well as significant hubs for goods movement.

Within the southwest region, the busiest air travel corridors exist between metropolitan areas and are consistent with travel along the I-15 corridor. Most of these metropolitan areas are separated by 300 to 500 miles. The long distances between major markets and lack of competitive service for this distance offered by the existing passenger rail network have led to a disproportionate reliance on short-haul flights for travel within the region. The busiest air travel corridor is between Los Angeles and Las Vegas.

Map of popular air travel corridors in the project area.