What's covered: There are two coverages (1) collision (2) other than collision (which used to be called comprehensive coverage.) You can chose to purchase both coverages or only other-than-collision, yet you can not purchase collision coverage alone.
What exclusions apply: Many exclusions apply to Part-D. You should always refer to your specific policy.
Who are the insured: Part-D applies to both covered and non-owned autos. This items has a rather legal explanation where it is recommended that you should consult your insurance agent or a legal consultant.
What happens when other insurance covers a claim: Generally, insurance company limits the coverage the lesser of (1) the actual cash value of of stolen or damaged property or (2) the amount necessary to repair or replace the property with other property of like kind and quality. Insurance company has a right to pay for the damages in money or to repair or replace damaged or stolen property.