One type of regulatory signs are traffic sign

Traffic sign

Traffic signs or road signs are signs erected at the side of roads to provide information to road users. With traffic volumes increasing over the last eight decades, many countries have adopted pictorial signs or otherwise simplified and standardized their signs to facilitate international travel...

s intended to instruct road users on what they must or should do (or not do) under a given set of circumstances. Other types may be signs located on streets and in parking lots having to do with parking, signs in public parks and on beaches or on or in architectural facilities prohibiting specific types of activities. The term regulatory sign describes a range of signs that are used to indicate or reinforce traffic laws, regulations or requirements which apply either at all times or at specified times or places upon a street

Street

A street is a paved public thoroughfare in a built environment. It is a public parcel of land adjoining buildings in an urban context, on which people may freely assemble, interact, and move about. A street can be as simple as a level patch of dirt, but is more often paved with a hard, durable...

 or highway

Highway

A highway is any public road. In American English, the term is common and almost always designates major roads. In British English, the term designates any road open to the public. Any interconnected set of highways can be variously referred to as a "highway system", a "highway network", or a...

, the disregard of which may constitute a violation, or signs in general that regulate public behavior in places open to the public.

Examples of non-traffic types of regulatory signs might be tow-away signs for vehicles without disabled parking stickers or no-smoking signs where there are laws prohibiting smoking.