In 1930, the UK Government introduced a law that required every person who used a vehicle on the road to have at least third-party personal injury insurance. Today, this law is defined by the Road Traffic Act 1988, (generally referred to as the RTA 1988 as amended) which was last modified in 1991. The Act requires that motorists either be insured, or have made a specified deposit (£500,000 in 1991) and keeps the sum deposited with the Accountant General of the Supreme Court, against liability for injuries to others (including passengers) and for damage to other persons' property, resulting from use of a vehicle on a public road or in other public places.
Auto insurance isn’t only great protection for your vehicle, it’s also the law. All states require some degree of insurance for your vehicle to protect you and other motorists. Coverage requirements will vary based on your financial responsibility for your car and your state’s requirements. Some states even require you to have liability insurance before you even get a license.
Yes, you surely can avail the NCB if you change your insurance provider at the time of renewing the policy. All you would need to do is producing a proof of the earned NCB from your current insurance provider. You can produce the original copy of your expiring policy and a certification that you haven’t filed any claim for the (expiring) insurance plan. A renewal notice or a letter stating that you’re entitled to the NCB from your previous insurance provider can be a proof for this.
In 1998, the Progressive Insurance company started a pilot program in Texas, in which drivers received a discount for installing a GPS-based device that tracked their driving behavior and reported the results via cellular phone to the company. The program was discontinued in 2000. In following years many policies (including Progressive) have been trialed and successfully introduced worldwide into what are referred to as Telematic Insurance. Such 'telematic' policies typically are based on black-box insurance technology, such devices derive from a stolen vehicle and fleet tracking but are used for insurance purposes. Since 2010 GPS-based and Telematic Insurance systems have become more mainstream in the auto insurance market not just aimed at specialised auto-fleet markets or high value vehicles (with an emphasis on stolen vehicle recovery). Modern GPS-based systems are branded as 'PAYD' Pay As You Drive insurance policies, 'PHYD' Pay How You Drive or since 2012 Smartphone auto insurance policies which utilise smartphones as a GPS sensor, e.g. . A detailed survey of the smartphone as measurement probe for insurance telematics is provided in 
For instance, if your automobile is registered in Chennai, the applicable charges for Zone A would be charged. Even if you shift to another town or city, the same charges would be applied. Likewise, if an automobile is registered in a town, Zone B premium charges are applicable. Later on, in case the vehicle own moves to a metro city, he would be charged the rate of the Zone B only
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.