If the younger driver is covering his own costs, it might be cheaper for him to take out his own policy but include one of the older, lower risk drivers from the household as a named driver (as long as the older drive will use the car). However, if the older driver is footing the bill for both policies, multi-car insurance may still work out cheaper.
Metromile also uses an OBDII-based system for their mileage-based insurance. They offer a true pay-per-mile insurance where behavior or driving style is not taken into account, and the user only pays a base rate along with a fixed rate per mile. The OBD-II device measures mileage and then transmits mileage data to servers. This is supposed to be an affordable car insurance policy for low-mileage drivers. Metromile is currently only offering personal car insurance policies and is available in California, Oregon, Washington, and Illinois.
In case there are any changes that need to be made in the policy such as address change or any particular changes regarding the automobile or its usage, it could be done by an endorsement by the insurance provider. You need to submit a letter to your insurance provider along with the proof of the changes so that you could obtain the endorsement. There are few endorsements that might charge an extra premium from you.
Yes, motor insurance is transferable to the purchaser of the automobile. All you have to do is inform in writing about the transfer to its insurance provider. The original owner of the car needs to fill out a new proposal form. A nominal fee is charged for the insurance transfer along with the recovery of No Claim Bonus from the transfer date till policy expires on a pro-rata basis.
 Availability varies. Enrollment discount applies during data collection; final discount is calculated on driving behavior and could be zero. Discounts do not apply to all coverage elements; actual savings vary by state, coverage selections, rating factors and policy changes. Final discount applies at the next policy renewal and remains until drivers or vehicles on the policy change.
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. 
State legislators set limits on how much a company can increase your rates after a crash. Our hypothetical accident resulted in only $2,000 worth of damage. That caused average annual rates to spike by $1,000 or more in some states, while others jumped by far less. One thing’s for sure: Your rates will definitely increase after an at-fault accident, so be sure to compare car insurance rates if you have one on record.
Any car insurance comparison tool you look at should have your state’s minimum car insurance requirements pre-loaded into its options. States requiring PIP or medpay are generally referred to as “no-fault” states, meaning that when injuries occur, each driver in a crash makes a claim with their own insurance company to pay for them. Beyond the PIP or medpay limit, the at-fault driver’s liability insurance kicks in to cover the rest.