A 30 km/h zone is also known as a ‘zone 30’ or a 'residential area'. The zone is mostly situated within an urban area and consists of connected access roads with a 30 km/h speed limit. The areas have a residential function where slow traffic and motorized traffic mix. For this reason speeds must be low (30 km/h maximum).

A progressive penalty system encompasses heavier or more far-reaching sanctions being imposed as one commits more offences. A progressive penalty system is often called a progressive fines system if it involves increasingly higher financial penalties (fines), but (other) recidivism schemes such as demerit points systems can also be seen as a progressive penalty systems.