Road Traffic Act Only Insurance differs from Third Party Only Insurance (detailed below) and is not often sold, unless to underpin, for example, a corporate body wishing to self-insure above the requirements of the Act. It provides the very minimum cover to satisfy the requirements of the Act. Road Traffic Act Only Insurance has a limit of £1,000,000 for damage to third party property, while third party only insurance typically has a greater limit for third party property damage.
You’ll notice that none of that liability coverage pays for your car or injuries, nor for any injuries your passengers sustain if you cause a wreck. This is why many people — particularly those whose car isn’t yet paid off — want “full coverage” car insurance. This isn’t actually a type of coverage, but instead typically refers to policies that include liability coverage, plus comprehensive and collision coverages.
The cheapest car insurance, period, will likely carry the minimum coverage required in your state. In most states, this is liability insurance only, which covers property damage and medical bills for others due to accidents you cause. Some states also require uninsured and underinsured motorist coverage, which pay for your injuries or damage if an at-fault driver doesn’t have enough insurance.
But liability coverage levels come in threes — you’ll probably see something like 50/100/50 up to 250/500/250 in typical policies. You can think of these limits like: individual injuries / total injuries / property damage. Insurers are a little more technical, calling them bodily injury liability, total bodily injury liability and physical damage liability.
Providers can also offer sub-divisions of auto repair insurance. There is standard repair insurance which covers the wear and tear of vehicles, and naturally occurring breakdowns. Some companies will only offer mechanical breakdown insurance, which only covers repairs necessary when breakable parts need to be fixed or replaced. These parts include transmissions, oil pumps, pistons, timing gears, flywheels, valves, axles and joints. 
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."