I-70 Winter Driving Tips: What Every Visitor Should Know

Every winter, thousands of visitors make the drive from Denver to the Colorado mountains along Interstate 70. Most of them arrive safely and have a wonderful trip. But every season, we also see pileups, stranded vehicles, and multi-hour closures that turn what should be a two-hour drive into an eight-hour ordeal, or worse.

Everything below is what we practice daily on our Denver to Vail private car service, dedicated winter tires and all.

We have been driving the I-70 corridor professionally since 2015. Here is what we wish every visitor knew before getting behind the wheel in a Colorado winter.

Understanding Colorado's Traction Law

Colorado's Traction Law is not a suggestion, it is an enforceable law, and violations carry real consequences. There are two levels you need to know:

Code 15, Traction Law

When Code 15 is activated, every vehicle on the highway must meet the requirements for its drivetrain:

AWD/4WD vehicles must have one of the following:

• Winter or mud/snow tires (mountain-snowflake or M+S marking) with at least 3/16" tread depth, or
• Chains or an approved alternative traction device (ATD)

Two-wheel-drive (2WD) vehicles must have chains or an approved ATD, there is no tire-only option. As of the 2025–26 season, 2WD vehicles are required to carry chains or an ATD from September 1 through May 31, regardless of what tires they have.

Code 15 is activated frequently throughout the winter, sometimes multiple times per week. It applies to the I-70 mountain corridor between Morrison and Dotsero, a stretch that runs well west of Vail.

Code 16, Chain Law

When conditions worsen, CDOT escalates to Code 16. Under this order, all vehicles must have chains or an approved traction device, yes, even SUVs and trucks with AWD/4WD. This is the "we mean it" level, and it is activated during heavy snowfall or when the road surface becomes dangerously slick.

The Eisenhower Tunnel: 11,158 Feet Above Sea Level, Bored Through the Continental Divide

The Eisenhower-Johnson Memorial Tunnel is the highest vehicle tunnel in the world at 11,158 feet above sea level. It sits at the Continental Divide and marks a critical weather boundary, conditions can be completely different on either side. You might have clear roads in Summit County and drive into a whiteout heading west toward Vail.

A few things to know about the tunnel:

• No hazardous materials or oversize vehicles are permitted, which means commercial trucks must use Loveland Pass (US-6), this frequently causes delays at the tunnel entrance during storms.
• Speed limits drop to 50 mph approaching and inside the tunnel.
• The tunnel creates a bottleneck that amplifies traffic during peak periods. On busy ski weekends, the backup can extend for miles.

Vail Pass: The Stretch That Demands Respect

Between Copper Mountain and Vail, I-70 climbs over Vail Pass at 10,662 feet. This 15-mile stretch is one of the most accident-prone sections of highway in Colorado, and for good reason. The road is steep, exposed to wind, and frequently covered in packed snow or black ice.

The eastbound descent from Vail Pass toward Copper Mountain is particularly treacherous. The grade is steep enough that CDOT has installed runaway truck ramps, and every winter, vehicles that rely on their brakes instead of downshifting end up in trouble.

Essential Resources for Real-Time Conditions

Before you leave for the mountains, check these sources:

• COtrip.org, CDOT's official travel information site with real-time road conditions, camera views, and closure information. This should be your first stop before any winter mountain drive.
• CDOT Twitter (@ColoradoDOT), Fast updates on closures, traction law activations, and estimated reopening times.
• Colorado 511, Call 511 from any phone for automated road condition reports.
• Waze / Google Maps, Useful for real-time traffic data, but they do not always reflect CDOT closures immediately.

Before You Head Up: A Quick Checklist

Whether you drive yourself or ride with a professional, a little preparation makes the trip smoother:

• Check COtrip.org for current conditions and closures before you set out
• Allow extra travel time on storm days and busy ski weekends
• Pack layers, water, snacks, and a phone charger in case of delays
• If you are driving yourself, verify your tires meet Traction Law requirements and carry chains or an approved traction device, and clear ALL snow off your vehicle before leaving
• If you would rather skip the rental car entirely, book a driver who already carries the right equipment for every condition

Why Many Experienced Visitors Just Hire a Driver

Here is something we have noticed over 10 years of mountain driving: our most frequent clients are not first-time visitors. They are families and groups who have made the Denver-to-Vail drive before, experienced the stress firsthand, and decided it was not worth it.

When you hire a professional mountain driver, you are not just paying for a ride. You are getting someone who has navigated Vail Pass in every condition imaginable, who carries proper chains and traction equipment at all times, and who knows every alternate route when I-70 closes. You are also getting your vacation time back, time to relax, take in the scenery, and arrive at your destination calm instead of white-knuckled.

The Colorado mountains are extraordinary, and getting here should be part of the adventure, not a source of anxiety. Whether you drive yourself or let us handle the road, the most important thing is arriving safely so you can enjoy every moment of your time in the Vail Valley.

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