All states have laws that prohibit drivers from making unsafe lane changes. State laws generally require a driver on a road with marked lanes to operate the vehicle within a single lane and to move to another lane only at a time and in a manner that is safe.

This means a driver may not cross more than one lane of traffic at a time, must allow a safe distance between the driver’s vehicle and other vehicles, and must signal the lane change with a blinker, as required by law. The failure to do so may result in a ticket or citation for an unsafe lane change.

The penalty for making an unsafe lane change usually includes a fine and demerit points on your driver’s license or record.

As with many traffic violations, the officer issuing the citation and the prosecutor have significant discretion in determining whether there was a violation of a traffic law and whether the violation constitutes a certain offense, as defined by the state legislature in the traffic code or in a municipal ordinance.

This discretion to issue a ticket or citation and prosecute the charge against the driver is balanced by the discretion of the jury or judge in determining whether the prosecution met its burden of proof sufficient to convict the driver (for a criminal offense) or find the driver responsible (for a civil infraction, violation, or offense).

In New Jersey, laws governing unsafe lane changes are outlined under Title 39 of the New Jersey Statutes. Specifically, N.J.S.A. 39:4-88 requires drivers to stay within a single lane and only change lanes when it can be done safely. Drivers must use turn signals to indicate their intention to change lanes, allowing sufficient time for other drivers to react. Failing to adhere to these rules can result in a traffic citation for an unsafe lane change. Penalties for such an offense typically include fines and may also result in points being added to the driver's license, which can affect insurance rates and driving privileges. The discretion of law enforcement officers and prosecutors plays a role in the issuance and prosecution of citations, while judges or juries determine the outcome of the case based on the evidence presented.