Route comparison websites

Very soon, it will be time for the ROSS Summer School. This is a nine-day event where participants put on a significant extract from a stage musical. It is the theatrical equivalent of drinking from a fire hose and, to carry the water analogy further, the pleasure of total immersion in the subject helps make it a fantastic event for all involved.

But that's not the point of the posting.

I wanted to work out how best to get there. So I tried a couple of route planning websites. What interested me was the different routes that they took, and the journey time that they predicted.

• Google Maps sent me down the A68 along this route. The journey would be 220 miles and take 5hr 1minute
• Microsoft's live.com kept me on the A1. Its journey was 235 miles, but only took 4hr 15minutes
• The AA decided that the M74/M6/A66 was a better route (as indeed did my Tom Tom on my phone). I can't make a link to its route, but it weighed in at 253 miles, 4hr 57minutes.

So obviously Microsoft's route is the one to go for. But I got slightly suspicious.

Google will let me modify the route by dragging the route onto roads that I choose. So, what happens if I modify the Google-calculated route to the same route as Microsoft chose? Does the journey miraculously become forty-six minutes faster?

Er, no. It becomes one minute faster. Five hours, zero minutes.

So the question has to be where the data comes from for expected speeds? Do the websites use real, time-of-day-weighted average speeds, or is it a more naive approach? You're on a dual carriageway, so you're expected to be doing 60mph?

I tried asking for information on the live.com feedback form, but got nothing in response. I think I'll ferret around a little more, though. I'll post any results here.