Final answer:
Generally, a proper turn signal must be given at least 100 feet before making a turn or changing lanes, but it's important to confirm with local traffic laws as this distance can vary.
Step-by-step explanation:
You must give a proper turn signal at least 100 feet before turning or changing lanes. This is a general traffic rule to ensure safety and communication with other drivers on the road. However, it's important to note that this distance can vary by jurisdiction, so it's essential to check local traffic laws for the exact requirement. The rule of giving a turn signal in advance allows other drivers and pedestrians to anticipate your actions and react accordingly, reducing the risk of accidents.