Auto collision covers losses due to collision with another car or object.  If you have a claim due to collison the insurance company will pay to repair or replace your vehicle (less your deductible).  Collision coverage will pay to repair or replace your vehicle regardless of fault. 

If you are involved in an accident with an uninsured motorist and they are at-fault,  your deductible would be waived if you selected (UDW),  which is waiver of deductible.

If you are financing your vehicle you may be required to have both collision and comprehensive coverage.

If you have any questions, contact your insurance agent or this author.