Variable Message Signs (VMS) are intended to provided information to travelers on roads (how long to nearby destinations, warning of an accident, there is an Amber Alert, please run a car with license plate XXX YYY off the road). In London they are used on underground and National Rail trains and at selected bus stops with the Countdown system installed.
I wish they were accurate.
A) I have been on a National Rail train (from London to Canterbury) that was set to divide into two parts, one to one destination, one to another. So far so good. According to the sign, the front four cars were going to point A, the rear four to point B. The problem, it was by visual inspection, a 12 car train, and I was, according to the sign on Car 9 of 8.
B) Countdown signs telling me a bus is due when it has already departed.
C) Countdown signs telling me the next bus will be X when in fact it is Y.
D) Signs on the Piccadilly Line trains telling me that I am on a train bound for Heathrow when in fact I had just departed Heathrow was on a train for Cockfosters. This was quickly corrected, but clearly indicates the signs on the trains are human controlled rather than automatic based on location on the network, and an afterthought.
E) Signs at tube stations telling me the train was going through to Edgware when in fact it was turned around at Hampstead, and those going farther had to exit the train and wait for the next one (see the previous post on dynamic rerouting).
F) Signs at Putney Bridge Station telling me the next train is for City via Victoria when in fact the sign on the train indicates it is going to Edgware Road via Paddington.
The problem is not simply that the signs are wrong some percentage of the time, it is that they undermine confidence in the system, and future information systems that might be accurate. Misinformation adds uncertainty to the system more than simply having no information at all.