A regional alternate route to I-15 will support long-distance travel, help divert detour traffic from over-congested local detours, and give travelers options. The I-15 Alternate Route Study documents the existing conditions and potential needs of this alternate route to I-15 connecting Salt Lake City, Las Vegas, Inland Empire and San Diego. A prioritized list of needed improvements has been developed and details are provided in the report.

Map of I-15 alternate routes in the project area.

A lack of alternative routes to I-15 exists. Major incidents that close I-15 cripple traffic, causing added congestion and lost economic dollars.

The 2014 Moapa flood forced the closure of 50 miles of I-15, requiring a 223-mile detour for truck traffic bound from Las Vegas to Utah – more than doubling the travel time. This resulted in an extra daily cost of $667,000 - $790,000 in trucking operations, not including the economic impact of delayed freight deliveries (ATRI, 2015).

The July 2015 Cajon Pass fire swept across I-15, resulting in more than 30 destroyed vehicles. Detour options exist, although none are direct and all pose additional hazards, ranging 20 to 50 miles out of direction on rural forest service roads. The Cajon Pass was closed again in August 2016 due to the Blue Cut Fire.