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 Hawaii, as in all states, laws are in place to ensure that drivers make lane changes safely. Hawaii Revised Statutes Section 291C-123 requires drivers to stay within a single lane and only change lanes when it can be done safely. Drivers must signal their intention to change lanes using their vehicle's turn signals. Failing to adhere to these rules can result in a citation for an unsafe lane change. The penalties for such an infraction typically include a monetary fine and may also result in demerit points being added to the driver's license record. The determination of whether a lane change was unsafe is subject to the discretion of the law enforcement officer who witnesses the maneuver, and the prosecutor who may bring charges. However, a judge or jury has the final say in determining whether the evidence presented meets the burden of proof to convict the driver in a criminal case or find them responsible in a civil matter.