Some classes of vehicle ownership, or use, are "Crown Exempt" from the requirement to be covered under the Act including vehicles owned or operated by certain councils and local authorities, national park authorities, education authorities, police authorities, fire authorities, health service bodies, the security services and vehicles used to or from Shipping Salvage purposes. Although exempt from the requirement to insure, this provides no immunity against claims being made against them, so an otherwise Crown Exempt authority may choose to insure conventionally, preferring to incur the known expense of insurance premiums rather than accept the open-ended exposure of effectively, self-insuring under Crown Exemption.
Widespread use of the motor car began after the First World War in urban areas. Cars were relatively fast and dangerous by that stage, yet there was still no compulsory form of car insurance anywhere in the world. This meant that injured victims would seldom get any compensation in an accident, and drivers often faced considerable costs for damage to their car and property.