Non-owner car insurance is for anyone who drives a car they don't own regularly or needs to prove coverage.

Non-owner car insurance is for persons who do not own a vehicle yet need to drive occasionally.

Perhaps you usually travel by train but sometimes hire a car on vacation or use a shared vehicle for long travel.

Liability car insurance compensates for injuries and property damage caused by you to others in a car accident.

However, the insurance does not cover any damage to the automobile you borrowed or rented. 

It also doesn't cover any injuries caused due to the crash.

Uninsured/underinsured motorist coverage is usually included in a non-owner car insurance policy.

The protection pays if you have been injured caused by a driver who doesn't have enough liability insurance.

It also covers Medical payments or personal injury protection, which you require for paying the medical bills.

Non-owner insurance also doesn't cover comprehensive or crash insurance, which the standard auto policy usually covers.

The policy is best suitable for those who don't have their vehicle. 

Your state may require SR-22 or FR-44 forms as the Insurers file them on your behalf to prove your minimum insurance coverage mandated by the state.