To measure a 2-second following distance, choose a stationary object along the side of the road, such as a sign or tree. As the vehicle in front of you passes the object, start counting seconds. Your vehicle should reach the same object approximately 2 seconds later. If your vehicle reaches the object before 2 seconds have elapsed, you are following too closely and should increase the following distance.
It's important to note that the 2-second following distance is just a guideline, and you may need to adjust the distance depending on the conditions, such as visibility, road conditions, and the speed of traffic. For example, in adverse weather conditions or when driving on unfamiliar roads, you should increase the following distance to give yourself more time to react.