One of the more complex and subjective traffic violations is an unsafe lane change. It can occur only when a road has at least two lanes traveling in the same direction, and the lanes have clearly marked boundaries separating them. For an officer to issue this type of ticket, the driver must have weaved out of their lane into another lane without taking precautions.
The main example of an unsafe lane change is when a driver is veering from one lane to another without signaling. An officer may spot a series of brake lights on cars in various lanes and reach the conclusion that a driver is behaving recklessly. There are certain defenses to this type of argument. A driver might point out that drivers around them were driving too fast, which required them to step on the brakes when a car moved into the lane in front of them. Or a driver might have needed to make a sudden lane change if a car in front of them braked abruptly. It can be challenging for an officer to make this type of judgment if they have an imperfect view of the scene. A driver can cross-examine the officer to establish gaps or flaws in their view.
A related violation to unsafe lane changes is improper passing, which can be defined in different ways depending on the state. Sometimes an officer will stop a driver for improper passing on the basis that their maneuver endangered one or more vehicles in the vicinity. This could be the vehicle that you were passing or a vehicle approaching from the opposite direction. Proving this type of violation is difficult unless an accident occurs, or the passing driver forces another driver off the road. If the vehicle being passed slows down to let the passing vehicle back into the lane, this does not necessarily mean that the passing maneuver was dangerous. The driver being passed may have acted out of excessive caution.
Improper passing based on a blind pass can be a harder violation to defend. This is because it is defined more objectively as passing while approaching the top of a hill or a blind curve. The idea is that the driver’s view of oncoming traffic is obstructed in these situations. A defense might involve challenging the officer’s impression of how far you were from the curve or hill. You might be able to argue that you had enough space to complete the maneuver before reaching the obstructed area, or that the driver being passed increased their speed, forcing you to complete the maneuver further down the road than you expected.
Most states categorically prohibit passing on the right except in narrow situations. A driver can pass on the right when the vehicle being passed is about to turn left, although they cannot drive off the pavement of the road to complete this maneuver. Also, a driver can pass on the right if the road is wide enough to make two lanes of traffic, even though the lane boundaries are not marked. For either of these exceptions to apply, the driver must be able to make the maneuver safely.