Two of the most important factors that go into determining the underwriting risk on motorized vehicles are: performance capability and retail cost. The most commonly available providers of auto insurance have underwriting restrictions against vehicles that are either designed to be capable of higher speeds and performance levels, or vehicles that retail above a certain dollar amount. Vehicles that are commonly considered luxury automobiles usually carry more expensive physical damage premiums because they are more expensive to replace. Vehicles that can be classified as high performance autos will carry higher premiums generally because there is greater opportunity for risky driving behavior. Motorcycle insurance may carry lower property-damage premiums because the risk of damage to other vehicles is minimal, yet have higher liability or personal-injury premiums, because motorcycle riders face different physical risks while on the road. Risk classification on automobiles also takes into account the statistical analysis of reported theft, accidents, and mechanical malfunction on every given year, make, and model of auto.
If a vehicle is to be "laid up" for whatever reason, a Statutory Off Road Notification (SORN) must be submitted to the DVLA to declare that the vehicle is off the public roads and will not return to them unless the SORN is cancelled by the vehicle's owner. Once a vehicle has been declared 'SORN' then the legal requirement to insure it ceases, although many vehicle owners may desire to maintain cover for loss of or damage to the vehicle while it is off the road. A vehicle that is then to be put back on the road must be subject to a new application for VED and be insured. Part of the VED application requires an electronic check of the MID, in this way the lawful presence of a vehicle on the road for both VED and insurance purposes is reinforced. It follows that the only circumstances in which a vehicle can have no insurance is if it has a valid SORN; was exempted from SORN (as untaxed on or before 31 October 1998 and has had no tax or SORN activity since); is recorded as 'stolen and not recovered' by the Police; is between registered keepers; or is scrapped.
A compulsory car insurance scheme was first introduced in the United Kingdom with the Road Traffic Act 1930. This ensured that all vehicle owners and drivers had to be insured for their liability for injury or death to third parties whilst their vehicle was being used on a public road. Germany enacted similar legislation in 1939 called the "Act on the Implementation of Compulsory Insurance for Motor Vehicle Owners."