Speed limits — Colorado Permit Test

Speed is the greatest factor influencing the severity of a crash.

The energy in a crash climbs faster than the speed does. Ten miles an hour less is the difference between a bad day and a funeral.

Speed is the greatest factor influencing the severity of a crash

Unless otherwise posted, the Colorado speed limit is 20 mph on narrow, winding mountain highways and blind curves.

On a blind curve you can only stop within what you can see, and that is a very short distance. The limit is set to match it.

20 mph on narrow, winding mountain highways and blind curves

Unless otherwise posted, the Colorado speed limit in any business district is 25 mph.

A business district is full of people stepping between parked cars. Twenty-five is about the fastest a driver can stop in time for one.

25 mph in any business district

Unless otherwise posted, the Colorado speed limit in any residence district is 30 mph.

Children, driveways and parked cars are all there and all unpredictable. The limit is a little higher than downtown because the crossings are fewer.

30 mph in any residence district

Unless otherwise posted, the Colorado speed limit on open mountain highways is 40 mph.

An open mountain highway still has rockfall, wildlife and curves that tighten without warning. Forty is the speed those leave room for.

40 mph on open mountain highways

Unless otherwise posted, the Colorado speed limit is 45 mph for vehicles in the business of hauling trash.

A loaded trash truck takes far longer to stop and stops often. It gets its own limit for both reasons.

45 mph for vehicles in the business of hauling trash

Unless otherwise posted, the Colorado speed limit on urban interstate and highways is 55 mph.

An urban interstate has traffic joining and leaving constantly. The limit is lower than the rural one because the merging never stops.

55 mph on urban interstate and highways

Unless otherwise posted, the Colorado speed limit on designated rural interstate and highways is 65 to 75 mph.

These are the roads with the fewest crossings and the longest sightlines, so the ceiling is the highest Colorado sets anywhere.

65-75 mph on designated rural interstate and highways

Cities or towns may adopt lower speed limits in their jurisdictions by ordinance.

The statewide figures are defaults, and a town knows its own streets. Where the posted number is lower, it is the one that counts.

City or towns may by ordinance adopt lower speed limits in their jurisdictions.

Some roads such as freeways have minimum speed limits posted, and driving slower than the minimum is a traffic violation unless road or weather conditions require it.

A slow car on a freeway is an obstacle everyone else has to swerve around. That is as dangerous as a fast one.

Driving slower than the minimum speed limit is a traffic violation, unless due to road or weather conditions

Regardless of the posted speed limit it may be necessary to reduce your speed, and signs will show when a reduced speed limit is in effect.

A limit is set for a good day. The driver, not the sign, has to judge what today is like.

Regardless of the posted speed limit, it may be necessary to reduce your speed to keep yourself and others safe

Driving much slower than the posted speed in normal conditions can affect the flow of traffic and create unpredictable, potentially unsafe situations.

Traffic works when everyone moves at about the same speed. A car well below it forces a stream of passes that need not have happened.

However, driving much slower than the posted speed in normal conditions can affect the flow of traffic and create unpredictable, potentially unsafe, situations.

What does the handbook call the greatest factor in how severe a crash is?

The speed of the vehicle. The energy in a crash climbs faster than the speed does. Ten miles an hour less is the difference between a bad day and a funeral. Colorado Driver Handbook, p.12: “Speed is the greatest factor influencing the severity of a crash”