The basic Car Insurance Requirements in Colorado are as follows:

Liability Insurance is a minimum requirement and a low cost car insurance option as long as the vehicle is not financed.

The liability Minimums are 25/50/15 (Bodily Injury and Property Damage)
25/30/5 Explained:

The first 15 represents $25,000, the maximum coverage for one person's injuries, $50,000 for the total coverage for all injuries sustained in one incident and last but not least $15,000 for the property damage maximum coverage amount.

Colorado Car Insurance Laws:
Insurance proof is a requirement at registration and of course after an accident. The First Offense Penalty is a $500 fine.