In NJ as in most cities and states across the nation, the likely answer is “it depends.” A person who walks their bike is considered a pedestrian in all jurisdictions and therefore the simple fact that they have a bicycle in their possession would not prohibit them from using a sidewalk. There is no NJ State statute which expressly prohibits one from riding a bicycle on a sidewalk, and the definitions applicable to Title 39 (NJ’s motor vehicle act) expressly exclude devices “moved by human power or used exclusively upon stationary rails or tracks or motorized bicycles” from its definition of “vehicle”. See N.J.S.A. 39:1-1. As such any prohibition against vehicular traffic on sidewalks should not apply to bicycles. This position is in accordance with statements on the NJ DOT’s website, which indicate that bicycles are not expressly prohibited from being ridden on sidewalks absent an applicable municipal ordinance.
Irrespective of legality, bicyclists should take note of the fact that that the principal purpose of a sidewalk is for pedestrian travel. The presence of a bicyclist on a sidewalk can place the cyclist in a position which others do not expect; a fact which may lead to increased risks to the cyclist and others and may lead to conflicts with pedestrians. As such, except for young cyclists riding under parental supervision, or situations in which the sidewalk offers the only safe refuge to the cyclist, a sidewalk should generally not be viewed as a primary path for the cyclist.