## Sunday, 18 August 2013

### goldfish brain

For the last eleven years and more, I’ve been driving between home near Cambridge, and work in York, nearly every week. I know the 350 mile round trip rather well by now. Despite this, I’ve taken to having the SatNav on during the journey. That’s because there can often be delays due to accidents, or road closures due to roadworks, and a little advance warning can let me choose a route more useful than the suggested diversion.

Last week, the inevitable happened. I was tootling up the A1 to York, when the SatNav advised me: “Road closed at J36 due to roadworks. Calculate alternative route?” Yes.

Whirr, whirr, whirr. “Confirm new route?” The map is very small, but I could see this new route at least approximated the M18 diversion I had already intended to take. So, yes, let’s take that one.

Pause. “Road closed at <somewhere I’d never heard of> due to roadworks. Calculate alternative route?” Okay, that’s a nuisance, so yes, calculate new route.

Whirr, whirr, whirr. “Confirm new route?” The map is very small, but I could see this new route looked close to the original A1 route.  But, hey.  Yes, confirm new route.

Pause. “Road closed at J36 due to roadworks. Calculate alternative route?”  Aargh! it had put me back on the original closed route.  I could guess what would happen next, but I tried it anyhow.  Yes, calculate alternative route.

Whirr, whirr, whirr. “Confirm new route?” Back on the M18 diversion. Yes, confirm. Pause. “Road closed at <somewhere I’d never heard of until a few minutes ago> due to roadworks. Calculate alternative route?”

Clearly the system has a diversion buffer of size one.  I decided to take the M18 diversion. Once I was on that bit of road, the system the quite happily found me a diversion around the diversion.

 (left) intended route, but the A1 was closed around Doncaster; (mid) SatNav suggested alternative, but then found to be closed somewhere south of Selby; (right) final SatNav suggested route, once commited to the M18 east of Doncaster

very #FirstWorldProblems