Driving of motor vehicles - Colorado

Federal regulations

Colorado has adopted Part 392 of the Federal Regulations.

Applicability

Part 392 applies to a self-propelled or towed vehicle bearing an apportioned plate or having a manufacturer’s gross vehicle weight rating or gross combination rating of at least 16,001 pounds. Part 392 also applies to a vehicle used on a public highway to transport a placardable amount of hazardous materials.

Engine idling

A commercial diesel vehicle with a gross vehicle weight rating of greater than 14,000 pounds that is designed to operate on highways may not idle for more than 5 minutes within any 60-minute period.

Exceptions — A vehicle may idle for up to 20 minutes in any 60-minute period when the outside temperature is less than 10°F.

A passenger bus is exempt from the prohibition when idling for up to five minutes to maintain passenger comfort when non-driving passengers are on board.

A vehicle may idle to heat or cool a sleeper berth during a sleep or rest period at a safety rest area, fleet trucking terminal, commercial truck stop, state-designated location designed to be a driver’s rest area, or a location where the vehicle is legally permitted to park that is at least 1,000 feet from residential housing, a school, daycare facility, hospital, senior citizen center, or medical outpatient facility providing primary, specialty, or respiratory care.

There are also exceptions for:

• Traffic conditions;
• Operation of defrosters, heaters, or air conditioners to prevent a safety or health emergency;
• Emergency vehicles;
• Vehicle maintenance or repair;
• Vehicle inspection;
• Operation of power take-off equipment if necessary for operating work-related mechanical or electrical equipment;
• Armored vehicles when a person remains inside to guard contents or while loading/unloading; and
• A critical service or a utility provider, when performing the functions of the provider’s duties.

Speed limit

The speed limit is 75 mph on specific sections of rural interstate, 65 mph on surfaced 4-lane interstates, 55 mph other highways, 40 mph open mountain highways.