The driver's knowledge is not superseded by technology. Transit times in London are heavily affected by factors not taken into account by SatNav devices. Road

The driver's knowledge is not superseded by technology. Transit times in London are heavily affected by factors not taken into account by SatNav devices. Roadworks, time of day, congestion patterns due to current events, and accidents, all can change optimal route selection by factors of 5 or even 10, and all are taken into account by the London cabbie. I would trust a London Black Cab driver's route selection over SatNav every time, without fail.