According to the European directive for consumer protection, customers can withdraw from the online purchase of a product or service within 14 days – this will also apply to the digital vignette. The day of purchase does not count as one of these 14 days. Plus: Since withdrawing from the purchase is also possible by post (not just email), the withdrawal notification can arrive at ASFINAG up to three days later.
The digital vignette is thus valid from the 18th day after the purchase; only then does it become valid for use on Austria’s motorways and expressways.
In other words: If you buy a digital vignette on 1 February 2018 through the ASFINAG web shop or the app, then the toll not valid until 19 February 2018.
This is to prevent drivers from purchasing the digital vignette online, using the motorway network and then getting their money back for the toll.