Colorado requires uninsured motorist coverage, but the law has specific limits on when you can use it

Colorado law requires every auto insurance policy to include uninsured motorist (UM) coverage unless you actively reject it in writing. This coverage pays your medical bills and damages if you are hit by a driver with no insurance or by a hit-and-run driver. The catch: you cannot collect from both the at-fault driver's policy and your own UM coverage for the same injury, and Colorado courts have narrowed when you can stack UM coverage across multiple vehicles.

The law sits in Colorado Revised Statutes § 10-4-609. It sets a floor—your policy must offer UM coverage at least equal to your liability limits, up to the state minimum of $25,000 per person and $50,000 per accident. You can buy more if you want. But the statute also creates a stacking restriction that changed in 2015: if you own multiple vehicles, you generally cannot add up their UM limits to recover more than the highest single limit you chose.

Understanding this law matters because it shapes what your claim is actually worth and what your insurance company can and cannot do when you file. It also determines whether you need a lawyer to push back on a low offer or a coverage denial.

Key Takeaways

  • Colorado requires UM coverage on every policy unless you sign a written waiver, and the minimum must match your liability limits up to $25,000/$50,000.
  • You can recover under UM coverage only if the other driver is uninsured, underinsured, or a hit-and-run—not if they have insurance that covers the claim.
  • Colorado's stacking ban means if you own two cars with $50,000 UM limits each, you recover a maximum of $50,000 total, not $100,000, unless you specifically bought stacking coverage.
  • Your own insurance company becomes the defendant in a UM claim, which creates a conflict of interest and often requires an attorney to negotiate fairly.
  • Disputes over UM coverage—whether the other driver was truly uninsured, whether your injuries exceed the limit, whether you can stack—frequently end up in arbitration or court.

When you can and cannot use uninsured motorist coverage

UM coverage only applies in three specific situations. First: the other driver has no insurance at all. Second: the other driver has insurance, but their policy limit is lower than your damages, and you have bought underinsured motorist (UIM) coverage—a separate add-on that Colorado does not require but many people buy. Third: the other driver fled the scene (hit-and-run) and you cannot identify them.

You cannot use UM coverage if the at-fault driver has insurance and their policy limit covers your claim. Even if their insurer is slow to pay or disputes liability, you must pursue that policy first. Your own UM coverage sits in the background. This is called the anti-stacking rule in practice: you get one recovery, not two.

The exception is underinsured motorist coverage. If the other driver has $25,000 in liability insurance but your damages are $75,000, UIM coverage (if you bought it) bridges the gap—up to your UIM limit. Colorado law requires insurers to offer UIM at the same limits as UM, but you can refuse it in writing, just as with UM.

Colorado's stacking restriction and what it costs you

Before 2015, if you owned two cars, each with $50,000 UM coverage, you could "stack" those limits and recover up to $100,000 from an uninsured motorist claim. Colorado changed this. Under the current law, stacking is banned by default. If you own multiple vehicles, your recovery is capped at the single highest UM limit across all your policies, even if you paid premiums on each one.

Example: You own a sedan with $50,000 UM and an SUV with $50,000 UM. You are hit by an uninsured driver while in the sedan. Your damages are $80,000. You can recover only $50,000 under the stacking ban, not $100,000. The second vehicle's coverage does not add to the first.

You can opt out of this ban, but you have to ask your insurer for stacking coverage as a separate endorsement, and it costs more in premiums. Few people know this option exists, and insurers do not advertise it. If you own multiple vehicles and have significant assets, stacking coverage is worth discussing with an agent or attorney.

How uninsured motorist claims work in Colorado

When you file a UM claim, your own insurance company becomes the party you are negotiating with—not the other driver's insurer. This creates a built-in conflict: your insurer has a financial incentive to pay you as little as possible. Colorado law requires them to act in good faith and handle the claim fairly, but disputes are common.

The process typically starts with notice to your insurer. You report the accident, provide police reports, medical records, and proof that the other driver was uninsured. Your insurer investigates. If they accept the claim, they may offer a settlement. If you disagree with the offer or if they deny coverage, you can demand appraisal or arbitration—a process where a neutral third party reviews the dispute.

Many UM claims settle without court. But if the amount in dispute is large, or if your insurer denies coverage outright, litigation becomes likely. Colorado courts have upheld insurer denials in cases where the claimant could not prove the other driver was actually uninsured, or where the claimant's injuries did not match the damages claimed.

Hit-and-run claims and the uninsured motorist exception

If you are hit by a driver who leaves the scene, your UM coverage applies even though you cannot identify the other vehicle. But Colorado law imposes strict conditions. You must report the accident to police within a reasonable time and cooperate fully with the investigation. You must also have a reasonable basis to believe you were hit by another vehicle—not just that your car was damaged.

Insurers frequently deny hit-and-run UM claims because they argue the claimant did not meet the reporting requirement or did not prove contact with another vehicle. If you are in a hit-and-run, document everything: the time, location, any witnesses, damage patterns, and the police report number. Report to police before you report to your insurer. This creates an independent record that strengthens your claim.

If your insurer denies a hit-and-run claim, you can challenge the denial in arbitration or court. The burden is on you to show you were hit, but Colorado courts have been relatively generous in allowing UM recovery when the evidence suggests a collision occurred.

Disputes over uninsured motorist coverage and when to involve an attorney

Common disputes arise over three issues: whether the other driver was truly uninsured, whether your damages exceed the UM limit, and whether you can recover under UM at all (versus being required to pursue another avenue first).

Your insurer may claim the other driver had insurance when you say they did not. This requires investigation—police reports, DMV records, the other driver's statements. If the evidence is unclear, arbitration or court decides. You may also dispute the value of your claim. Your insurer offers $30,000; you believe your injuries are worth $60,000. This is a damages dispute, not a coverage dispute, and it often requires informed testimony from doctors or economists.

You should consider hiring an attorney if your insurer denies coverage outright, if the gap between their offer and your damages is large (generally $10,000 or more), or if the claim involves a hit-and-run or stacking dispute. Attorneys who handle UM claims work on contingency in many cases, meaning they take a percentage of the recovery rather than an upfront fee. This makes representation affordable even if your claim is modest.

Frequently Asked Questions

Can I reject uninsured motorist coverage in Colorado?

Yes, but only in writing. Your insurer must offer UM coverage on every policy. If you want to decline it, you sign a waiver. Few people do this because UM coverage is relatively inexpensive and protects you against a real risk—roughly one in eight Colorado drivers is uninsured. Rejecting it is usually a mistake unless your financial situation is very tight.

What if the other driver has insurance but it does not cover the accident?

That is different from being uninsured. If their policy excludes the accident (for example, they were using the car for commercial purposes and their policy excludes that), you may still have a claim against them personally, but UM coverage does not explore. You would need to sue the driver directly or pursue underinsured motorist coverage if you have it and their policy limit is below your damages.

Do I have to go to arbitration before I can sue over a UM claim?

Colorado law allows your insurer to require arbitration for UM disputes, but you can refuse and go to court instead. Arbitration is usually faster and cheaper, but a court judgment is binding on both sides. Arbitration awards can sometimes be challenged. Discuss this choice with an attorney if the amount in dispute is significant.

If I settle a UM claim, can I still sue the uninsured driver later?

Once you settle with your insurer, your insurer has a right to recover what they paid from the uninsured driver (called subrogation). But you generally cannot pursue the driver separately for the same injury. Read your settlement agreement carefully—it should specify what rights you retain.

Does Colorado require me to buy underinsured motorist coverage?

No. Colorado requires UM coverage but not UIM. However, UIM is worth considering if you have significant assets or high medical expenses. Many accidents involve drivers with low liability limits ($25,000), and UIM bridges the gap between their limit and your actual damages. Discuss this with your agent when you renew your policy.