Rubber-tire trolleys can add to the atmosphere of a neighborhood and provide a quick method of transit in a small, clearly defined area. Also known as tourist trolleys, these are vehicles designed to look like traditional streetcars. They differ from bus systems however, in that they are not designed primarily for commuters, but seek to serve casual riders. In downtowns or other areas where parking is difficult, pedestrians can leave their cars in designated locations and use the trolley service to move more freely around the neighborhood. Rubber-tire trolleys are often used as circulators, moving constantly between points of interest and other public transit stops.