🇺🇸 United States · All states

Driving in Colorado

The rules foreign visitors most often get wrong — with the official source for every fact. Always verify directly before you drive.

Colorado is the Rocky Mountain state — I-70 carries the main east–west traffic through the Eisenhower Tunnel (11,158 ft elevation, second-highest road tunnel in the US). The Front Range corridor (Denver, Boulder, Colorado Springs) on I-25 is heavy commuter traffic; the mountain corridor on I-70 is heavy ski-resort traffic in winter and recreation traffic in summer.

Colorado's defining seasonal phenomenon is the I-70 ski-corridor traffic between Denver and the resorts (Vail, Breckenridge, Copper Mountain). Friday afternoon and Sunday evening produce 4–5 hour delays on what should be a 90-minute drive. The CDOT chain law triggers at the lowest weather levels and is strictly enforced.

Colorado's hands-free phone law took effect January 1, 2025 — handheld use is now banned for all drivers in all situations.

The headline rule

I-70 Mountain Express Lane (eastbound) — peak-hour-only, dynamic toll

The eastbound I-70 between Empire and Idaho Springs has a peak-period Mountain Express Lane that opens only during heavy-traffic conditions (typically Sunday afternoons returning from ski resorts). Toll is dynamic and signed at entry. Solo drivers must use the ExpressToll transponder or be billed by plate; HOV-3+ rides free with a HOV switch on the transponder. Foreign drivers in rental cars almost always end up paying via the rental company's pass programme.

Key rules

Max rural interstate speed
75 mph[1]

Rural I-70 sections

Right turn on red
Permitted after full stop (unless signed otherwise)[1]
Seatbelt enforcement (front)
Secondary enforcement[2]

Primary for under-16

Handheld phone
Banned for all drivers[3](as of 2025-01-01)
Texting while driving
Banned[3]
Min liability — bodily injury per person
$25,000[4]
Min liability — bodily injury per accident
$50,000[4]
Min liability — property damage
$15,000[4]
Motorcycle helmet
Required for some riders (see notes)[5]

Under 18 only

Move-over law
Yes — required to move over / slow for emergency vehicles[6]
Studded tires
unverifiedSee notes — verify with the state authority.

Allowed seasonally; exact rule needs direct verification from CDOT

Marijuana in vehicle
Open container / consumption in vehicle illegal[7]

CRS §42-4-1305.5 — open marijuana container in passenger area prohibited

Famous driving routes in Colorado

Tips for foreign visitors

Tolls in Colorado

Colorado E-470 (the Denver ring road), Northwest Parkway, and the I-70 / I-25 ExpressLanes use ExpressToll. The I-70 Mountain Express Lane is dynamic-priced peak-only. Rental drivers should sign up for the rental company's pass programme or accept the plate-billing fee.

Primary resources for Colorado

Sources

Every claim above links to its numbered source here. If a link is broken, or you believe a fact is outdated, please let us know.

  1. [1]CDOT — I-70 Deer Trail East Project — CDOT · accessed 2026-04-23
  2. [2]CDOT — Primary Seatbelt Laws — CDOT · accessed 2026-04-23
  3. [3]Colorado Hands-Free Law (SB24-065, eff. 2025-01-01) — CDOT · accessed 2026-04-23
  4. [4]Colorado DORA — Auto Insurance — CO DOI · accessed 2026-04-23
  5. [5]CDOT — Motorcycle Laws — CDOT · accessed 2026-04-23
  6. [6]NHTSA — Move Over, It's the Law — NHTSA · accessed 2026-04-23
  7. [7]CRS §42-4-1305.5 — Marijuana Open Container in Vehicle — Colorado Legislature · accessed 2026-04-23