This guide is for general information only and is not legal advice. Laws change — verify current rules with your state DOT or a licensed attorney before relying on this for any legal matter. Read full disclaimer.
The rule
New Jersey requires front headlamp emitting a white light visible from at least 500 feet to the front. For the rear, red rear lamp visible from at least 500 feet to the rear (a reflector alone does not satisfy the statute — a lamp is mandatory). a red reflector may be added on top of the lamp. The rule applies whenever it is dark. See N.J. Stat. § 39:4-10.
The cheapest way to stay legal in New Jersey is a USB-rechargeable front white light and a rear red light or reflector that meets the spec above. A $30 light set covers it.