RequirementsTo rent a car, you must be at least 21 years old (age may vary by car category) and have held your license for 1 year. All licenses from EU member states and the USA are

recognised in Austria, otherwise an International Drivers License is required. Drivers under the age of 25 may incur a young driver surcharge. Seatbelts are mandatory and children up to age 12 are required to use an appropriate restraint.
TollsAustria requires all vehicles using the autobahn to display a highway toll sticker. Rental cars in Austria should come with a valid toll sticker - check before driving off. Stickers are available at the border or gas stations when entering from another country.
Speed LimitsSpeed limits in Austria are as follows: City - 31mph/50kph, Open Roads - 62mph/100kph, Highways -81mph/130kph.
GasGas stations are generally open 8am to 8pm with some stations in major cities open 24 hours.
Parking“Blaue-Zone” parking areas noted by blue lines on the road. The zones require a time imprinted parking disc, as there is a 3 hour parking limit. Parking discs can be obtained in banks, nearby shops, or from automated disc machines in the parking area.