Tuesday 16 December 2008

The new knowledge

Now that SatNav is affordable, anyone can drive round like they know the secret ways of the city. Whereas before the knowledge gave those who studied it an edge, now there is nothing to stop anyone getting a minicab license and driving round the city with as accurate an understand of the ways round it as you'd gain from years of learning. How then can a commercial taxi driver make money and ensure that there is still a barrier to entry to competitors.

Simple: a new knowledge. The commercial SatNavs know the one way streets. That is a strength: you don't need to know them, but also their great weakness. Their routing algorithms assume that you can only traverse a one-way street in the direction the arrows point. That is, the collection of streets, the graph, is a directed graph. Experts in the city can use this to their advantage. By knowing exactly which little one-way street they can nip down, they can come up with a more optimal routing through the city. For example, ask a SatNav how to get from Kingsdown to Cheltenham Road, and it will come up with two solutions, neither of which work well at 17:10 on a weekday.
1. Cotham Brow (busy), Arley Hill (long queue)
2. Horfield Road, Park Row, Jamaica Street.
A driver with The New Knowledge will know another solution. The one way bit at the bottom of Nugent Hill. It does bring you out into Arley Hill, but if there is a big traffic jam., you've missed it.

This blog strives to avoid making any accusations that could be considered libellous, and therefore does not state whether this taxi, the Jaguar with the Bristol City Taxi #2036 license plate on it, has done any such action. Instead, we will say: if they had done something like that at about 17:00 hours on Thursday December 11, 2008, they had better not have had their SatNav unit turned on, because those little units not only make suggestions on where to go, they record where you went. So if this taxi had driven the wrong way down the Nugent Hill one-way-section, the car would remember the fact.

Which is another piece of knowledge you need to remember, isn't it. The SatNav may be your friend, but only your friends can betray you.

[Reg # PX55SVL]


SP said...

So, presumably you saw the Jaguar with the Bristol City Taxi #2036 license plate on it go the wrong way down the Nugent Hill one-way section at 17:00 hours on Thursday December 11, 2008.

Have I understood that right? :)

Chris Hutt said...

Apparently a lot of collisions with cyclists have resulted from that manoeuvre.

Motorists joining Arley Hill via illegal use of the one-way section at the bottom of Nugent Hill are only expecting one way traffic from Cotham Brow and are not aware of the contra-flow cycle lane coming up from Cheltenham Road, so frequently collide with cyclists legitimately using this.

Still, the cyclists have probably committed some minor traffic offense themselves over the previous few months, so deserve what they get (in the view of many motorists).

Anonymous said...

Arley Hill is one of the most unfriendly parts of the city for cyclists, even though it tries hard to put on a smiley face.

I don't think many drivers know that the cycle lane is meant to be two-way; and for cyclists heading up the hill, the same lane mysteriously stops half-way towards Redland Road, leaving you no choice but to cycle the wrong way up a one-way street.

If cycling city money is ever to be spent, a good place to spend it would be here.

Dru Marland said...

...though Arley Hill does become two-way as you approach Redland Road. I used to live in Arley Park and was heading up to Cotham one day on my motorbike when an approaching car ostentatiously tried to block me. The driver wound down the window and told me in that I've Been Driving For A Long Time And Know What I'm Talking About voice, that I shouldn't be doing that. By the time I'd ordered up my witty response, he was lorng gorn. Dammit.

Rick said...

"because those little units not only make suggestions on where to go, they record where you went."

What makes you think that. Mine doesn't record anything (or are the pro units for taxis different)?

Bristol Dave said...

SatNavs don't record where you've been, other than a list of previously-chosen destinations.

The storage space required would be phenomenal.

SteveL said...

Mountaineering/sailing,handheld GPS units do record routing; they play tricks by recording location at specific times, or only when you change direction. They can also do some rolling three-days-worth of data storage, and do some compression of older data (drop timestamps). Data storage is cheap.

I know the satnavs that a lot of delivery vans use do this tracking as there are OpenStreetMap videos of london that show how the vehicles start off on the main roads then branch off onto back roads. I'd assume the premium GPS units that some taxi companies use would be similar. It lets the taxi company monitor driver speed, routing, etc.

SteveL said...

Regarding arley hill,

* because it is one-way at the bottom, nobody driving down it expects cars heading towards Cotham brow: very entertaining.

* the bumps are good on a mountain bike, not road bike

* Nugent hill is trouble. We need to discourage cars from using it. I find asking people if they "knew about the camera" good.

* Another troublespot with Nugent Hill is that when descending at speed, cars will pull out onto it from side roads, as they know there won't be any vehicles heading straight on. Which can be bad news if you are heading straight on; had a bit of a fright in the ice ten days ago when I nearly lost the front wheel steering round the junction. I think its actually safer to do nine-tree hill and the unofficial contraflow at the bottom there.