In many European countries, such as Norway and Germany, it is a requirement to always have a reflective jacket in the car.

The following european countries have introduced mandatory reflective jackets in the car:

Austria
Belgium
Bulgaria
Croatia
France
Germany
Hungary
Italy
Luxembourg
Norway
Portugal
Slovenia
Slovakia
Spain

In Austria and Italy, there is a law that there should be as many reflective vests as the number of people traveling in the car.

(Source: Motormännens Riksförbund)