Children must use a child restraint system suitable for their weight and/or height until their seat belt can be properly fastened (this is usually the case when they are 150 cm tall). We may travel across countries with stricter or more lax rules, or with tighter or more lenient legislation when it comes to traveling with small children in the car. If we are driving in a country where there is no clear legislation or it is far too lenient, safety should always come first and we recommend that children travel in a suitable child car seat even if it is not compulsory to do so.