What is Closing Speed?
Closing speed is essential in situations where collision avoidance is a concern. Drivers must know the closing speed between their vehicle and others to ensure safe driving and appropriate reaction times.
Closing speed is often used to explain the potential damage caused by two vehicles having a head-on collision. If vehicle A is doing 60mph and vehicle B is doing 60mph, the closing speed would be 120mph.
120mph can be given as a rough example to emphasise the dangers, though other factors would have to be taken into consideration to provide an exact closing speed, such as:
- The angle of the two vehicles on impact
- Vehicle types – if vehicle A is a lorry and vehicle B is a Mini Cooper, vehicle B would suffer more
- If the incident occurs on an incline/decline
- Where the vehicles finished after the collision
Another factor to consider when looking at closing speed is the weight of the vehicles involved. Someone driving a large lorry doing 60mph will likely come away with fewer injuries than someone driving a small car if they both hit each other at 60mph. On top of that and after impact, the small car would go backwards as the lorry’s weight would follow through.
The best way to avoid having this type of collision is to know about the following:
- Vanishing points/Dead ground
- How to an emergency stop and be fully aware of your stopping distances.
- Fully understand good car control and how to control your car. For example, when driving someone else’s car, the brakes may respond very differently to your car. This is normal, so until you have grasped the new car’s controls, drive with much more caution.
Where do most head-on collisions happen?
Most head-on collisions happen on rural roads, usually near a bend in the road. One of the leading causes of this type of accident is the speed of at least one of the vehicles involved. When a vehicle is approaching a bend too fast, it’s common for the driver to position their vehicle closer to the centre of the road. Incidents like this increase the chances of an accident, especially if a larger vehicle, such as a lorry, is around the corner.
Another reason is poor overtaking decisions. The two most common overtakes that end in a head-on collision is when the driver thinks they can make it when an oncoming vehicle is approaching, on the brow of a hill or on a bend again.
Top tip from Lee Serwatka – Providing driving lessons in Leeds:
“Closing speed accidents can be avoided if everyone driving thinks, ‘What if?’
If you are thinking of overtaking a large combine harvester approaching a slight bend 200 meters away, you should ask yourself: what if a fast car came flying around that bend? Could I 100% make it without affecting the car on the bend, the combine harvester or any other road users? If the answer is 100% yes, then proceed with the overtake. If the answer is 99% yes, then don’t do it.”
