I-40 California Road Conditions

I-40 crosses 155 miles of California, from the Arizona line to its end in the state. That is 6% of I-40's 2,555 miles.

Inside California it meets I-15 at Barstow.

By mile marker, I-40 passes Barstow 0. It is the only city on this stretch that the mileposts name.

6 current reports along the route. The 3 most serious are listed below. Always check with the responsible state DOT before setting off.

• Lanes blocked

  I-40 mainline closure (lanes 1)

  Mainline closure. Work: Pavement Repair. Lanes closed: 1. Near Yermo, San Bernardino County.

  Yermo • East • CA • Until Oct 9, 11:59 AM

• Lanes blocked

  I-40 off ramp closure

  Off Ramp closure. Work: Pavement Repair. Lanes closed: All. Near Yermo, San Bernardino County.

  Yermo • East • CA • Until Oct 9, 11:59 AM

• Lanes blocked

  I-40 on ramp closure

  On Ramp closure. Work: Pavement Repair. Lanes closed: All. Near Newberry Springs, San Bernardino County.

  Newberry Springs • East • CA • Until Oct 9, 11:59 AM

Towns Along I-40 in California

From Barstow to Needles, with the position of each town measured along this stretch itself — counted from the Barstow end, not from a state milepost, so it will not match the numbers on the signs.

1. 0 mi Barstow 2.2 mi off the road
2. 143 mi Needles 1.8 mi off the road

Places from the US Census Gazetteer and population estimates, both public domain; distances measured along this page's own route geometry.

California Chain Controls: R-1, R-2 and R-3

The sign states the rule; R-1, R-2 and R-3 are what you hear on the radio. Caltrans does not post signs with those designations — they are shorthand it and the CHP use internally, which traffic reports then repeat. What is posted at the roadside is the requirement and the list of who is exempt, and which of the three levels is up decides whether snow tires are enough — or whether anything is. Caltrans is explicit that the sign wins: follow it, and any instruction from Caltrans or CHP staff at the checkpoint, even where it differs from a broadcast report or from a page like this one.

What R-1, R-2 and R-3 require

A snow-tread tire here carries MS, M/S, M+S or the words MUD AND SNOW on the sidewall and has at least 6/32-inch of tread — the same depth as Colorado's 3/16-inch, written the other way round. Chains means any approved traction device: link chains, cable chains, textile snow chains, hub-mounted and automatic chains all count, and Caltrans and the CHP can turn away a vehicle whose device does not meet the Vehicle Code.

R-1

Chains on everything except a car or light truck under 6,000 lbs with snow tires on at least two drive wheels — and that car still has to be carrying chains.

R-2

Chains on everything except four-wheel drive under 6,500 lbs with snow tires on all four wheels, again only if a set of chains is in the vehicle. This is where two-wheel drive stops being enough however good the tires are.

R-3

Chains on all vehicles, no exceptions, four-wheel drive included. Caltrans notes a highway is often closed before it goes this far, so R-3 usually means the road is about to shut.

Enforcement

Non-compliance is a citation from the California Highway Patrol, which is who enforces chain control rather than Caltrans; no fixed amount is published.

How you will know it is active

• Signs posted along the controlled stretch, stating the requirement and who is exempt from it — not the R-number, which Caltrans does not sign
• QuickMap, which carries statewide chain controls and refreshes them every minute
• The Caltrans Highway Information Network on 800-427-7623, which covers California and western Nevada, the Lake Tahoe and Reno area included

Which requirement is posted changes with the storm and with the elevation. This page does not carry it — QuickMap ↗ is the authority before you set off.

Source: Caltrans, checked September 22, 2026.

Related Roads

I-40 in California Road Weather FAQ

Is Interstate 40 in California closed right now?

No full closures are reported on I-40 in California as of Oct 8, 2026 8:47 PM PDT. 6 lane closures, roadworks or restrictions are in force. They are listed under closures and road blocks on this page.

What are I-40 in California road conditions today?

The map on this page colors the route along I-40 in California by what is on the pavement right now — dry, wet, slush, snow or ice — from radar and surface data, last updated Oct 8, 2026 8:33 PM PDT. Right now temperatures run from 84°F to 92°F and the strongest wind is 7 mph.

What do R-1, R-2 and R-3 mean in California?

A snow-tread tire here carries MS, M/S, M+S or the words MUD AND SNOW on the sidewall and has at least 6/32-inch of tread — the same depth as Colorado's 3/16-inch, written the other way round. Chains means any approved traction device: link chains, cable chains, textile snow chains, hub-mounted and automatic chains all count, and Caltrans and the CHP can turn away a vehicle whose device does not meet the Vehicle Code.

What happens if you ignore a California chain control?

Non-compliance is a citation from the California Highway Patrol, which is who enforces chain control rather than Caltrans; no fixed amount is published.

Do I need chains to drive I-40 in California in winter?

Not always. It depends which of 3 requirements is posted: "R-1" — chains on everything except a car or light truck under 6,000 lbs with snow tires on at least two drive wheels — and that car still has to be carrying chains. "R-2" — chains on everything except four-wheel drive under 6,500 lbs with snow tires on all four wheels, again only if a set of chains is in the vehicle. This is where two-wheel drive stops being enough however good the tires are. "R-3" — chains on all vehicles, no exceptions, four-wheel drive included. Caltrans notes a highway is often closed before it goes this far, so R-3 usually means the road is about to shut.

Do I need chains in California with four-wheel or all-wheel drive?

You have to carry them either way. All-wheel drive counts as four-wheel drive here, and no vehicle may enter a chain control area without a set of chains for one drive axle in it. Under R-2 a four-wheel or all-wheel drive vehicle under 6,500 lbs with snow tires on all four wheels may drive without them fitted; under R-3 there is no exemption for anyone. Towing a trailer means chains on a drive axle whatever you are driving, and a trailer with brakes needs them on at least one axle of its own.

Are there live traffic cameras on I-40 in California?

Yes. This page shows one live view on I-40 in California from the state transportation departments' own camera feeds, further down the page, refreshed each time you load it.

How often are I-40 in California road conditions updated?

The road surface and weather layers are rebuilt whenever this page is opened with data more than ten minutes old, and refreshed on a schedule in between, so nothing here is more than about two hours old even on a road nobody has looked at. Closures and road blocks are re-imported from the state 511 feeds every fifteen minutes, and the written state-by-state summaries are refreshed daily. Every section on this page carries the time its data was fetched.