Final answer:
Turn signals must be used before you plan to turn or change lanes to effectively communicate your intentions to other drivers and maintain road safety.
Step-by-step explanation:
You must use your turn signals before you plan to turn or change lanes. It is crucial for maintaining road safety and communicating your intentions to other drivers. The specific timing for signaling varies by jurisdiction, but a common rule is to activate your turn signal at least 100 feet before the turn or lane change in urban or residential areas, and a longer distance on faster roads. This helps to ensure that drivers behind and alongside you have sufficient notice and can respond accordingly to avoid collisions.
Aside from being a legal requirement, using turn signals is an essential part of defensive driving. It allows other road users to anticipate your actions, thereby making driving more predictable and reducing the chances of accidents. A good driver habitually signals well in advance, checks mirrors, and looks over the shoulder if necessary, before making a turn or changing lanes.