Managed care
In terms of using such a plan, unlike an HMO plan, which has a copayment cost share feature (a nominal payment generally paid at the time of service), a PPO generally does not have a copayment but offers a deductible and a coinsurance feature. The deductible must be paid in full before any benefits are provided. After the deductible is met, the coinsurance benefits apply. If the PPO plan is an 80% coinsurance plan with a $1,000 deductible, the patient pays 100% of the allowed provider fee up to $1,000. The insurer will pay 80% of the other fees, and the patient will pay the remaining 20%. Charges above the allowed amount are not payable by the patient or insurer but written off as a discount by the physician.
Vehicle insurance in the United States
Uninsured/Underinsured coverage, also known as UM/UIM, provides coverage if an at-fault party either does not have insurance, or does not have enough insurance. In effect, the insurance company pays the insured medical bills, then would subrogate from the at fault party. This coverage is often overlooked and very important. In Colorado, for example, it was estimated in 2009 that 15% of drivers were uninsured. 
Usually the limits match the liability limits. Some insurance companies do offer UM/UIM in an umbrella policy.