When must you signal a turn or lane change?

Answer: B — At least 100 feet before the maneuver

Signaling a turn or lane change at least 100 feet before the maneuver is crucial for maintaining safety and providing adequate notice to other drivers. This advance warning helps other road users, including vehicles and pedestrians, anticipate your movements and respond accordingly. By giving sufficient notice, you allow other drivers to adjust their speed and position, which can significantly reduce the risk of collisions. Choosing this timing aligns with best practices in safe driving and is often a requirement in many traffic laws, including those in Massachusetts. It promotes clearer communication on the road and fosters a safer driving environment. Additionally, signaling too late or not at all can lead to confusing situations for other drivers, increasing the likelihood of accidents. The other options do not represent the best practices for signaling. For instance, signaling less than 100 feet before a maneuver may not provide adequate warning time for surrounding vehicles. Similarly, signaling only in the presence of other vehicles fails to account for situations where you are merging, turning, or changing lanes with no immediate approaching traffic, where clear intent still needs to be communicated to ensure everyone's safety on the road.