Daily Archives:July 15th, 2008

Below average

In the UK we’re getting more and more stretches of road with ‘average speed checks’. Rather than simply measuring your speed as you pass a particular camera (or a particular policeman), your time over a distance between cameras – typically a few miles – is measured and you’re fined if your average speed exceeds the limit.

I’m not very keen on this, and I have some concerns about the amount of time I then spend looking at my speedometer, but I must admit the system does seem to do its job rather well; I imagine it will become the norm on most of our roads in due course.

Now, averages are funny things, of course. If you’re stuck in traffic for half the distance between two cameras, and moving at half the speed limit, you could then go infinitely fast for the other half and still be within the appropriate average. I imagine the authorities are banking on people not realising this.

Yesterday, as I drove a long stretch of monitored road, I was thinking about creating a system which would let you know what your personal real effective speed limit was at any time. It would need to know the positions of the cameras, but such a database could be built pretty quickly.

And then I realised that my car already has a partial solution built in: a ‘trip’ facility which can tell me the average speed over the length of the trip.

I just needed to press the trip-reset button as I went under a camera, and then I had a nice simple way to keep my average speed within limits until I reached the next one.

So until my next company, Below Average Inc., builds the full all-singing, all-dancing speed management product, this is very handy!

© Copyright Quentin Stafford-Fraser