There is inclement weather; i.e. rain, snow, ice and fog
There is a mechanical defect in one of the involved vehicles
Speed is definitely a factor
Last but not least, the driver of the other vehicle has a medical issue
Avoiding Rear-End Collisions
Allowing a larger spacing in wet conditions
Not overestimating the movement of the vehicle directly ahead of you, as well as recognizing the traffic flow ahead
Allowing a larger spacing when following large vehicles that block your view of the road ahead
Avoiding Rear-End Collisions
Recognizing your vehicle's braking ability and allowing a larger spacing when your vehicle is heavily loaded
Adjusting your speed when entering into an intersection operated by traffic control signals
Avoiding Rear-End Collisions
Allowing a larger spacing when following smaller, lighter vehicles, such as motorcycles, that can stop more quickly than you
Planning your trip to allow for adequate travel time
Allowing an aggressive driver to pass you rather than have him tailgate
Avoiding Rear-End Collisions
Make sure brake lights and turn signals are working, and use them correctly
In emergency stopping situations flash your brake lights to warn drivers behind you
Frequently glance in your rear view mirror, including when stopped at an intersection
Stop a car length short of intersections or crosswalks and keep your wheel straight to allow room to roll ahead if struck from behind. This could give you room for evasive action if required.