Auto liability coverage is the only coverage required by law.   This shouldn't be the only reason to have auto liability insurance.  Liability insurance covers the one large unknown we have ie.  how much could we be sued for if at fault in an accident resulting in someone's bodily injuries or fatalities.  Understanding the purpose of liability insurance will help you decide how much coverage is needed to cover losses for which you are legally liable.

Legally Liable: Liability Insurance Coverage
Auto insurance can include liability insurance coverage for accidents involving bodily injury and/or property damage for which the policyholder is legally liable. In other words, liability protection is the coverage that pays for injuries and damage sustained by a third party and/or their property for which you are responsible.

Insurance that Covers Bodily Injury (BI)
If you cause an accident and someone is injured, your liability coverage as part of your automobile insurance will pay for their injuries. Minimum amounts of liability insurance are often required by state law, however higher limits are recommended. Policies with split limits (i.e. 30/60/25) of liability separate the amount of insurance coverage available for each injured person and the amount of coverage available for the accident. For example, an insurance policy with split limits of 30/60/25 means $30,000 is the maximum amount payable by the policy for the bodily injury per person; $60,000 is the maximum payable by the policy per accident; the third number deals with property damage, which is discussed below. Other insurance policies have a combined single limit (e.g. $100,000). Combined single-limit policies offer a single amount that is the maximum amount payable by the policy for bodily injury and property damage.

Insurance that Covers Property Damage (PD)
If you cause an accident and someone else's property is damaged, your automobile insurance liability coverage will pay for the damage. In an accident, damaged property often includes the other driver's vehicle. However, property damage insurance coverage will also pay for damage to other types of property, such as a sign or light pole or building.

In insurance policies with split limits (i.e. 30/60/25), the third number indicates the maximum amount payable by the policy for property damage per accident. Combined single-limit policies offer a single amount that is the maximum amount payable by the insurance policy for bodily injury and property damage.

Required Minimums for Liability Insurance Coverage
Some states require drivers to carry a minimum amount of liability insurance for property damage. Higher limits are usually available.

Is there any way to predict the severity of an accident or how many people may be involved before it happens? Because the answer to this question is "no," higher limits of liability insurance coverage are always recommended.