What should you do if you cannot see the vehicle’s taillights in heavy rain?

In heavy rain, visibility can be significantly reduced, making it difficult to see the taillights of the vehicle ahead. Increasing your following distance is the safest action to take in this scenario. This allows for a buffer zone that gives you more time to react to sudden stops or changes in speed. When you're further away, you can better assess the situation, and if the vehicle ahead slows down or stops suddenly, you will have ample space to brake safely without the risk of a collision.

Choosing to follow closely behind is dangerous because it reduces your reaction time and increases the likelihood of an accident if the car in front brakes unexpectedly. Getting off the road immediately can be impractical and may lead to additional hazards, such as blocking traffic or losing visibility to other vehicles. Turning on your hazard lights is useful for alerting others of your vehicle, but it does not improve your ability to see the taillights of the vehicle ahead or provide the additional stopping distance you may need in such poor visibility conditions. Thus, increasing your following distance is the most appropriate and effective choice in this situation.