When driving on Austrian Motorways you are obliged to buy a sticker which is valid for one year and costs EUR 92.50 (you can buy it from December of the year before). The 2021 Vignette comes in apple-green. The new years's Vignette must be applied by 31st of January 2021 and is valid until 31st of January 2022.
The Vignette is available in post offices, Tabak Trafiken and gas stations. You can also get a 2-month-sticker which costs EUR 27,80 and a 10-days-sticker which costs EUR 9,50 (suggestive if you buy a car at the end of the year).
(In the picture: Vignette for 2021.)
There is also the option to buy a Digital Vignette at this link: https://shop.asfinag.at.
Calling with the mobile phone is prohibited by law while driving a car in Austria. If you like to call although you have to buy either a handsfree set or park the car. Watch out: Also when you are waiting at traffic lights or in a traffic jam calling on the mobile phone is forbidden.
It is obligatory to use winter tires from 1.11. to 15.4.. Drivers who violate this law will get fines from € 35,00 to € 5.000,00. In case of an accident, when driving without winter tires during winter season, although the driver isn't guilty, the insurance company won't pay any damages and the driver will be criminally prosecuted.