MileCheckWhy does I-70 close so often in Colorado?
I-70 in Colorado closes for crashes and for vehicles stuck on steep grades in snow, often around Vail Pass or the Eisenhower Tunnel. CDOT also slows traffic on purpose with metering at the tunnel, the Traction Law and the Chain Law, which it calls the last step before closing the highway.
Construction at Floyd Hill adds holds and overnight closures through 2029. (CDOT) Check live CDOT events on our Eisenhower Tunnel and Vail Pass pages before you leave.
Why does traffic stop before the Eisenhower Tunnel?
That is safety metering. When traffic is heavy, or after a crash or bad weather, a signal on the approach lets cars in every four to eight seconds. The goal is to keep the 1.7-mile tunnel from filling with stopped cars, because emergency crews could not reach a problem inside it. (CDOT)
CDOT says drivers may sit about 20 minutes at the signal, but the trip only takes about 3.5 minutes longer, because traffic past the tunnel is slow anyway. On busy days the eastbound on-ramps at Copper Mountain, Frisco, Silverthorne and Loveland are metered too. (CDOT)
Why does Vail Pass close?
Vail Pass is a long, steep grade, and one car or truck that can't climb in snow can block a lane. That is why CDOT fines drivers more when a car without proper tires closes a lane. Avalanche control can also close mountain roads at any time. (CDOT) See the camera and current events on our Vail Pass page.
What is the Traction Law on I-70?
- When. Sept. 1 to May 31 between Morrison and Dotsero, and any other time CDOT turns it on.
- Tires. At least 3/16 inch of tread and an M+S, M/S or mountain-snowflake rating. 4WD or AWD with that tread meets it.
- Or carry chains. Chains or an approved traction device also meet it.
- Chain Law. In a severe storm every vehicle needs chains or an approved device. CDOT calls this the final step before closing the highway.
Breaking either law is $100 plus a $33 surcharge. If your vehicle causes a lane to close, it is $500 plus a $157 surcharge. (CDOT) Our Colorado chain law page has the full rules.
Why is I-70 closed at Floyd Hill?
CDOT is rebuilding I-70 from Floyd Hill to the Veterans Memorial Tunnels, west of Denver. The work brings overnight closures in one direction at a time and holds for bridge work and rock blasting. Westbound moves to its new alignment by the end of 2027, eastbound by the end of 2028, and the project finishes in 2029. (CDOT)
What does our data show?
In September 2026, before snow, MileCheck logged 297 CDOT events on I-70 in Colorado. That is 63 percent of the 471 I-70 events we saw across the ten states where we saw I-70 events. Most were construction. Winter counts go in our monthly road report.
How do I know if I-70 is closed right now?
- Check CDOT. COtrip.org or 511 has closures, metering and Traction Law status. (COtrip) MileCheck reads CDOT's feed on our Colorado road conditions page.
- Look at the tunnel and pass cameras. A camera shows snow and traffic. Read the event list too.
- Check seasonal roads before you plan a detour. Many Colorado mountain roads close for winter. See Colorado seasonal closures.
See the closure before you reach it
Your mile marker shows even offline. Live state DOT feeds and the nearest camera on your route are part of MileCheck Premium and need a connection to update. Runs on CarPlay and Android Auto.
Questions, answered
Why does I-70 close so often in Colorado?
Closures come from crashes and from vehicles stuck on steep grades during snow, often near Vail Pass or the Eisenhower Tunnel. CDOT also meters traffic before the tunnel, holds traffic for construction at Floyd Hill, and uses the Chain Law as the last step before closing the highway.
What is safety metering at the Eisenhower Tunnel?
A signal on the approach lets cars through every four to eight seconds so traffic does not back up inside the 1.7-mile tunnel. CDOT says drivers may wait about 20 minutes at the signal, but the actual delay is about 3.5 minutes.
When is the Traction Law in effect on I-70?
From Sept. 1 to May 31 between Morrison and Dotsero, and at other times when CDOT activates it. Tires need 3/16 inch of tread and an M+S, M/S or mountain-snowflake rating, or you carry chains or an approved traction device. 4WD and AWD with that tread also meet it.
What is the fine for breaking the Traction Law in Colorado?
$100 plus a $33 surcharge. If your vehicle causes a lane to close, $500 plus a $157 surcharge.
Why is I-70 closed at Floyd Hill?
The I-70 Floyd Hill Project is rebuilding the highway between Floyd Hill and the Veterans Memorial Tunnels. It brings overnight closures and traffic holds. CDOT says the project finishes in 2029.
How do I know if I-70 is closed right now?
Check COtrip.org or call 511. MileCheck shows CDOT events on its Eisenhower Tunnel and Vail Pass pages and on the Colorado road conditions page.
Checked against CDOT on October 15, 2026. Conditions change by the hour, so check the live feed before you drive.