Wednesday, 15 April 2009

Laws of Physics Persist: In Crashes, Big Cars Win

These links are to MIT’s Technology Review which reports on a study that shows that even though small cars such as Minis and Smart cars do well in standard “crash into a wall” crash tests, they do less well in “real world” collisions with bigger vehicles because of conservation-of-momentum physics. The actually experienced crash forces on people in the smaller vehicles in head-on impacts are much greater. Click for article - In Crashes, Big Cars Win 

This is interesting. Locally, we already hear people defending their purchase of large 4x4s because they “feel safer”. This study suggests that in certain situations they are right.  This might lead to an “arms race” whereby people, in pursuit of safety for themselves, purchase ever bigger and heavier vehicles.

click for video of crash testing

The problem is, they are purchasing extra safety for themselves at the cost of reducing safety for others who either choose to drive smaller vehicles for environmental reasons or cannot afford a larger one.

In a totally free market which couldn’t care less about the climate one could see that Jersey’ites would all end up driving giant Hummers at enormous cost to our carbon footprint. Surely this new information strengthens the case for the authorities to introduce measures to steer people away from purchasing vehicles which not only use more fossil fuel to do the same job as smaller vehicles (horse box owners and towable boat owners get a free pass on this), but also expose more responsible people to extra risk?

I can’t resist cross posting this comment on the article from “Malkmus”! Watch out X5s and Cayennes!

“If, as the study suggests, large cars present a bigger hazard to other road users, why not restrict the speed of all cars to the same damage potential instead of the same speed. As the example in the study shows, a heavy car at 27 mph would pose the same threat to others as a light car at 50 mph. Hence a speed limit of 30mph for the heavy car and 50 mph for the light car should make them about equally dangerous for other road users. Since speed limits are presumably there for the safety of all road users, tying speed limits to vehicle weight seems a sensible system. Incidentally since fuel consumption is related both to vehicle size and speed this would reduce the consumption of fuel more efficiently by slowing down those cars that consume most fuel. Another thought: If heavy cars inflict larger damages to other road users, shouldn't the insurance premium on those cars reflect this. In particular on a crash where the weight of one of the cars was instrumental in causing harm to the occupants of the other vehicle shouldn't the heavier car be partly responsible for the damages, regardless of the cause of the accident itself. This would be a little like other liability cases where buying and using a product that increases the risk to others makes the user partly liable for damages when they occur”.

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