Interstate 40 in California

Interstate 40 (I-40) is a major east–west Interstate Highway in the United States, stretching from Barstow, California, to Wilmington, North Carolina. The segment of I-40 in California is sometimes called the Needles Freeway. It passes through the eastern fringe of the Inland Empire metropolitan area, going east from its western terminus at I-15 in Barstow across the Mojave Desert in San Bernardino County past the Clipper Mountains to Needles, before it crosses over the Colorado River into Arizona east of Needles. All 155 mi of I-40 in California are in San Bernardino County.

Route description


I-40 goes through the Mojave Desert on the entirety of its run through California. The highway starts its eastward journey at a junction with I-15 in Barstow. The freeway passes through Marine Corps Logistics Base Barstow before leaving the city limits. I-40 provides access to the town of Daggett but passes south of the town. After passing south of the Barstow-Daggett Airport, I-40 goes through Newberry Springs and Ludlow before traveling along the south end of Mojave National Preserve. Several miles east of the preserve, I-40 intersects U.S. Route 95 (US 95), and the two highways run concurrently into the city of Needles. In Needles, US 95 continues south while I-40 continues east through Mojave National Preserve and across the Colorado River into Arizona. The maximum speed limit for the entire California segment of I-40 is 70 mph.

I-40 is part of the California Freeway and Expressway System and is part of the National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration. I-40 is eligible for the State Scenic Highway System, but it is not officially designated as a scenic highway by the California Department of Transportation. I-40 from I-15 to the Arizona state line is known as the Needles Freeway, as named by Senate Concurrent Resolution 1 in 1968.

History
In 1957, the California Department of Highways proposed that the route be numbered as I-30 because of the already existing US 40 in the state. However, this was rejected, and, eventually, US 40 was decommissioned in favor of I-80.

Today, the Needles Freeway replaced the former US 66 across the Mojave Desert. As a result, a number of communities along the former route, like Amboy, have become ghost-towns.

In the early 1960s, Project Carryall, a component of Project Plowshare, would have detonated 22 nuclear explosions to excavate a massive roadcut through the Bristol Mountains to accommodate a better alignment of I-40 and a new rail line. This proposal was abandoned by the California State Department of Highways in 1968. The section between Ludlow and Needles was constructed using conventional explosives and excavation and designed with culverts for migrating Bighorn sheep and water tanks. It opened to traffic on April 13, 1973.

A sign at that start of I-40 in Barstow showing the distance to Wilmington, North Carolina, had been stolen multiple times.

Related routes
California does not have any auxiliary Interstate Highways associated with I-40.

One business loop of I-40 exists in the state, running through Needles. It is also designated as Historic Route 66 since it follows the former routing of US 66.