Auto collisions are a sad fact on California highways, and not all at-fault motorists own enough insurance—or any insurance—either. To help shield motorists and passengers from being left financially exposed following an accident, California law makes it possible to include Uninsured Motorist (UM) and Underinsured Motorist (UIM) coverage as optional features of a typical auto insurance policy. These types of coverage offer essential protection when the party at fault in an accident does not have the means to pay for the damage or injuries they’ve inflicted.
This article describes what UM and UIM coverage is, when it applies, how it functions in California, and why it is so vital in personal injury cases.
What Is Uninsured Motorist (UM) Coverage?
Uninsured Motorist (UM) coverage protects you if you are injured in an accident caused by another driver who does not have auto liability insurance. Despite California law requiring all drivers to maintain minimum coverage, a significant number of motorists on the road remain uninsured.
UM coverage typically applies to:
- Drivers and passengers in your vehicle
- You, as a pedestrian or cyclist hit by an uninsured driver
- Hit-and-run accidents where the at-fault driver cannot be identified
In these cases, your own UM policy steps in to cover your damages up to the limits of your policy.
What Is Underinsured Motorist (UIM) Coverage?
Underinsured Motorist (UIM) coverage applies when the at-fault driver does have insurance, but not enough to cover the full extent of your injuries and losses. If their liability limits are too low to compensate you fairly, your UIM policy may cover the difference—up to your own policy limit.
For example, if your damages total $100,000, and the at-fault driver’s insurance only covers $30,000, your UIM coverage can potentially provide the remaining $70,000 (assuming your policy limit is high enough).
California Requirements for UM/UIM Coverage
In California, insurance companies are required to offer UM and UIM coverage when selling a new auto policy. The minimum limits offered must be at least:
- $15,000 per person
- $30,000 per accident
However, drivers are not legally required to purchase UM or UIM coverage. If a policyholder declines the coverage, they must do so in writing.
Many drivers mistakenly waive this important protection to save money on premiums—only to regret it when they are injured by someone who is uninsured or underinsured.
How Does UM/UIM Coverage Work?
If you’re injured in an accident caused by an uninsured or underinsured driver, the UM or UIM portion of your own insurance policy may step in to pay for:
- Medical expenses
- Lost wages
- Pain and suffering
- Future care needs
- Other economic and non-economic damages
You do not have to sue the uninsured driver (who may have no assets) to receive this compensation. Instead, you file a claim with your own insurer under the terms of your UM/UIM policy.
In the case of UIM coverage, you must first exhaust the other driver’s policy limits before your own coverage will apply. This means that the other driver’s insurer must pay their full policy limits before you can collect the difference from your UIM policy.
Who Is Covered by UM/UIM Insurance?
California UM/UIM policies typically cover:
- The named insured
- Family members living in the insured’s household
- Passengers in the insured vehicle
- The insured person while walking or biking (if struck by an uninsured or hit-and-run driver)
Coverage is generally vehicle-specific, meaning it applies to injuries involving the covered vehicle or policyholder.
Hit-and-Run Accidents and UM Coverage
UM coverage can also apply in hit-and-run cases, but there are specific requirements:
- The accident must be reported to law enforcement promptly (typically within 24 hours)
- There must be physical contact between vehicles
- You must notify your insurer of the accident within a reasonable time
Without meeting these conditions, your insurer may deny the UM claim.
Common Disputes in UM/UIM Claims
Even though you’re dealing with your own insurance company, these claims can be adversarial. Common issues include:
- Disagreements over who was at fault
- Disputes about the extent or value of injuries
- Delay or denial of claims
- Low settlement offers
In many cases, claimants need legal representation to compel their insurer to pay fair compensation under the terms of the policy.
Stacking of Policies
California does not allow stacking of UM/UIM policies across multiple vehicles or policies. This means you cannot combine the limits of two separate policies to increase your payout unless explicitly permitted by the contract.
Arbitration Requirement
Most UM/UIM policies in California include mandatory arbitration clauses. If there is a dispute over the value of your claim, it will often be resolved through binding arbitration rather than a jury trial.
While arbitration can be faster, it also limits procedural rights and appeals. Having an attorney who understands arbitration is critical to achieving a favorable outcome.
Statute of Limitations
The statute of limitations for UM/UIM claims is more nuanced than regular personal injury claims. While a personal injury lawsuit in California generally has a two-year limitation period, UM/UIM claims are subject to contractual limitations based on the insurance policy terms.
Typically, you must:
- File a claim with your insurer promptly
- Begin arbitration (or litigation, if permitted) within a specified period after exhausting the other driver’s policy or learning the driver is uninsured
Delays in filing can lead to the denial of otherwise valid claims.
Why UM/UIM Coverage Matters
UM and UIM coverage provides a vital financial safety net. Without it, you may be left to pay for medical bills, lost wages, and other damages out-of-pocket, especially if the at-fault driver has no insurance or insufficient limits.
Given the high cost of serious injuries and the number of uninsured drivers in California, carrying adequate UM/UIM coverage can be one of the most important choices you make when purchasing auto insurance.
How an Attorney Can Help with UM/UIM Claims
Insurance companies often dispute UM/UIM claims even when coverage clearly applies. An experienced personal injury attorney can:
- Review your policy and determine coverage limits
- Handle communications with your insurer
- Prove the uninsured or underinsured status of the at-fault party
- Gather medical and accident evidence to support your claim
- Represent you in arbitration or litigation if necessary
An attorney can also help you avoid common pitfalls, such as accepting low offers or missing filing deadlines.
About the Author
Neil Bhartia
Neil Bhartia isn’t your typical, stuffy attorney that you see on TV. While some have their sights exclusively on money and treat their clients like a number, Neil takes a personal interest in every single client he has. As an empath, Neil understands that people that seek legal help are typically in an involuntary, and stressful situation, and he goes out of his way to diffuse the stress and educate clients on each every detail of the legal process.
