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 Wisconsin, state statutes require drivers to make lane changes safely and in accordance with the law. Drivers must stay within a single lane and only change lanes when it is safe to do so, ensuring not to cross multiple lanes of traffic at once and maintaining a safe distance from other vehicles. Wisconsin law mandates the use of turn signals when changing lanes. Failure to adhere to these rules can result in a citation for an unsafe lane change, which typically carries a fine and may add demerit points to the driver's license record. Law enforcement officers have discretion in issuing citations, and prosecutors have discretion in bringing charges. However, if the case goes to court, it is up to the judge or jury to determine if the prosecution has met its burden of proof to convict the driver of a criminal offense or find them responsible for a civil infraction.