Which of the following is a common cause of a rear-end collision?

Following too closely behind another vehicle, often referred to as tailgating, is a primary cause of rear-end collisions. When a driver does not maintain a sufficient distance from the vehicle in front, they may not have enough time to react to sudden stops or slowdowns. This lack of stopping distance can lead to a collision if the vehicle ahead brakes unexpectedly. It's important for drivers to keep an adequate following distance, allowing them ample time to respond to the actions of the car in front of them and thus avoid these types of accidents.

While changing lanes without signaling, turning left in front of oncoming traffic, and driving above the speed limit can all contribute to various types of collisions, they do not specifically address the scenario of a rear-end collision as directly as following too closely does.