All states have laws that prohibit drivers from making an illegal or improper turn. Common examples of illegal or improper turns are:

• U-turns (when there is a No U-Turn sign)

• Making a right or left turn without first moving to the far right or left lane

• Making a right or left turn when there is a sign at the intersection that prohibits such turns (No Right Turn).

The penalty for making an illegal or improper turn usually includes a fine and points on your driver’s license.

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 Idaho, as in all states, there are specific laws that govern the legality of vehicle turns. Idaho state statutes outline the rules for making legal turns, and these rules include prohibitions against U-turns where indicated by signage, requirements to move into the appropriate lane before making a turn, and adherence to any posted signs that restrict turns at an intersection. Violating these rules can result in penalties such as fines and points on the driver's license. The enforcement of these laws is at the discretion of law enforcement officers, who can issue citations based on their judgment of the situation. Prosecutors then decide how to proceed with the charges. If the case goes to court, it is up to the judge or jury to determine if the prosecution has proven the case beyond a reasonable doubt for criminal offenses, or by a preponderance of the evidence for civil infractions. The specific Idaho statutes that detail the regulations for turns and the associated penalties can be found in the Idaho Statutes Title 49 (Motor Vehicles), Chapter 8 (Signs, Signals, and Markings), and Chapter 6 (Rules of the Road).