Engineering for safety

Plaxton Premiere Volvo B10M
Originally uploaded by inglian.

Yesterday there was a report about a coach overturning due to dangerous driving - the driver was arrested on suspicion of being drunk. Earlier in the year, another coach overturned. And ten years on, there is still discussion about how Princess Diana was killed. Was it dangerous driving or was there a conspiracy?

What does not seem to get much of a mention is the contribution of engineering design towards safety or the lack of it.

Princess Diana's car could not have ended up running into a concrete column in Britain or other countries where potential hazards are protected by ARMCO barrier. This is the corrugated steel strip used in the centre reservation of motorways and can be seen in the left of the picture.

And now take a look at the coach, which is a standard contemporary design with a high floor.

Single deck buses and coaches from the 1940s and earlier had low floors with the engine at the front. But then came the underfloor-engined single-decker with a higher floor. This was also an essentially sound design as the heavy engine was mounted low.

But for the past couple of decades, coaches have had high floors with a luggage space beneath, and often a toilet as wall. This is obviously an advantage to passengers and operators, but it must inevitably raise the centre of gravity, making the vehicle less stable on curves and in cross-winds, and more easily overturned.

Is this something that needs to be examined?