Two second rule definition
The minimum gap or distance between two vehicles travelling in the same direction. As the vehicle in front of you passes a particular mark on the road or sign along the road, count two seconds and your vehicle should pass the same mark or sign. If road conditions are poor, the gap should be extended to three seconds or more. If you are following less than two seconds, there is not sufficient time to react to emergency evasive manoeuvres to avoid the possibility of hitting the vehicle in front.