There are three different types of direction arrow that are painted on the road surface. Those that consist simply of an arrow with one or two heads, those that consist of an arrow with destination or route information (car park, north, ring road etc.), and those that consist of an arrow with a command (turn left, turn right or ahead only). The first two types provide guidance to drivers as to the appropriate lane to be used. The third type may only be used where they indicate the effect of a statutory prohibition. These markings are used to reinforce a green arrow traffic signal or a regulatory turn sign. It is compulsory to obey this form of arrow.