New Jersey Tire Regulations

They consider two-thirty-seconds of an inch to be the minimum legal tread depth.

39:3-73. Tire-chains Motor vehicle tires may be fitted with tire-chains of reasonable proportions when roads, streets and highways are slippery, because of rain, snow, ice, oil, manner of construction or other reason; provided, however, that no tire-chains shall be used at any time on improved highways when highway conditions do not make such use necessary for the safety of life or property. No person shall use any tire-chains so constructed or installed as to be likely to be thrown so as to endanger any person or property.

No person shall drive or move any motor vehicle equipped with solid rubber tires unless every such tire shall have rubber on its entire traction surface at least one inch thick above the edge of the flange of the entire periphery. No person shall drive or move any motor vehicle or trailer upon the public highways, unless such motor vehicle or trailer is equipped with tires in safe operating condition in accordance with requirements approved by the director.

The director shall promulgate rules of safe operating condition capable of being employed by a law enforcement officer for visual inspection of tires mounted on vehicles including visual comparison with simple measuring gauges. Said requirements shall encompass effects of tread wear and depth of tread. A tire shall be considered unsafe if it has: (1) any ply or cord exposed; or (2) any bump, bulge or knot affecting tire structure; or (3) any break repaired with boot or patch; or (4) worn so that the tread wear indicators contact the road in any two adjacent major grooves at three locations spaced approximately equally around the outside of the tire. Nothing herein shall apply to farm vehicles registered under section 39:3-24 of this Title. Any law enforcement officer, at any time, upon reasonable cause to believe that a vehicle is unsafe or equipped with tires in violation of the provisions of this section or of the rules promulgated hereunder, may require the operator of such vehicle to stop and submit such vehicle to an inspection. If the inspection discloses the vehicle to be in violation, the officer may issue a summons for such violation. Officers of the Division of State Police shall have the exclusive authority to conduct random roadside examinations of any motor vehicle or combination of vehicles to determine whether their tires conform to the provisions of this section, any other applicable State laws or regulations or Federal rules and regulations pertaining to motor carrier tire safety. State Police officers shall have the authority, with or without probable cause to believe that a motor vehicle or combination of vehicles is unsafe or equipped with tires in violation of State and Federal tire safety provisions, to require the driver, operator, owner, lessee or bailee of the motor vehicle or combination of motor vehicles, to stop, drive or otherwise move to a location for tire inspection.

A person who operates a motor vehicle or combination of vehicles on any public road, street or highway with unsafe tires, as defined in subsection a. of this section, shall be subject to a fine of not less than $100 or more than $1,200, a term of imprisonment not to exceed 15 days, or both.

ftp://www.njleg.state.nj.us/20042005/S1500/1305_I1.PDF