If its an official vehicle, how can it be personal?
For all official purposes you will be allotted a vehicle. Sometimes, you would have to car pool and sometimes a single vehicle will be allotted. It depends on the station and the availability of the car. It is not to be used for your personal needs.
As per government rules, vehicles are not allotted on a personal basis until the JS rank.
Accommodation is available quite easily to IA&AS officers. In most places they have exclusive IA&AS colonies and don’t have to wait for the central pool.