It is issued automatically if you present your valid state driver's license. Don't leave your U.S. license at home, however. You should carry both your state license and your International Driver's License. Before you decide to drive while abroad, remember that a car can be very isolating. Your reality becomes the inside of the car, not the culture of the country.
Car accidents are the leading cause of death for travelers.
The biggest challenge is driving on the left, which is the custom in the United Kingdom, Australia, Hong Kong and several other countries throughout the world. Allow at least a week to get used to driving on the left. When driving or getting around using public transportation, think in kilometers, if that's the standard measure. Some local rental agencies are cheaper than the big name places. Also, some agencies will not rent cars to people over 70 or under 25.