It's safe to say most of us have a love/hate relationship with traffic lights: we love how they make traffic manageable on a large scale, and we hate their stupid, red-faced arrogance as they demand we stop and go just because they say so. We don't usually think of them as dangerous. But the very first one sure was.
Here's something else fascinating about the humble traffic light: it's way older than you'd think. The first traffic light appeared in 1868, and while that doesn't exactly predate cars, it certainly predates, by a long shot, even the slightest mass adoption of cars. Aside from the very rare steam-powered omnibus, the first traffic light was meant to deal primarily with the sort of vehicles that have manes, love apples, and defecate prodigiously.
That first traffic light was designed by John Peake Knight, and was placed at the intersection of Great George and Bridge Streets, just outside of the House of Parliament. The streets had gotten so busy with carriages and people (partially the result of the relatively new rail system bringing more and more people into London) that Knight, a railway signal engineer, decided to adapt the semaphore signaling system used on the railroads to normal road traffic.
The apparatus he designed was fairly simple: a tall pole with a pair of semaphore arms. When the arms were both sticking straight out, traffic was to stop. When the arms dropped to a 45° angle, you could proceed with caution. This system was meant to mimic the actions of a traffic cop's arms that people were already familiar with.
Here's a description from The Engineer, December 11, 1868:
As regards the design of the pillar, Mr. Hodgson, their manager, dotes not seem to have restrained himself by the rigid rules of any particular "order," but he has, nevertheless, contrived to present an imposing street ornament that will not be at all out of keeping whth even such ornate decorations in stone and iron as are presented in New Palace-yard hard by.
The pillar has a total height above thie ground level of 24ft. The centres of the semaphore arms are 18ft. high, and the centres of the magnifying lemses above each arm, which show the red and green lights corresponding with the positions of the arms, are 20ft. 4in. high. The lenses are 6in. in diameter, and the semaphore arms 4ft. long, 12in, broad at the outer end, reduced by a curve on each edge to 6 in, broad at the necks.
The pillar is octagonal in form at the base and the top, and the upper part of the shaft is round, with a spiral coil. At the bottom it is 1ft 8in in diameter, diminishing upwards at set stages, divided by projecting mouldings. The sides of the pillars are ornamented with gothic and diaper panelling.
The crankwork of the semaphore arms is fitted in a cleverly designed swell, over which there is an upper neck, and above that an ornate light box, with a sloping roof crocketed on the angles, and surmounted by a pine-apple finial. The pillar is a very good casting, and of about five tons in weight. The mechanism is cleverly contrived, and so nicely adjusted as to secure rapid and very smooth and easy working. The changes of position can be given, without any strain in the effort, by a lady or a youth.
The only notable novelties in the mechanical arrangements are those by which four arms, two of which are at right angles with the other two, and four lamp discs are acted upon at the same time, by a single pull or push of the connecting bar.
A "pine-cone" finial! Classy! Plus, this thing was "gilt-bordered" all over the place, making modern traffic lights look like piles of crap.
There was one criticism of the signal light, however:
The pillar has one defect in its design that cannot fail to attract notice —the absence of four or mere handsome brackets, carrying gas lamps for general lighting. The old lamps of the refuge look very dwarfish and seedy beside their new neighbours.
So, it didn't have street lighting. Okay. But it did have a lanterns with red and green lenses for night use, with red and green meaning just what we think they do.
Those red and green lanterns, despite making their neighbors look "dwarfish and seedy," also had one other huge issue that led to the signal's rapid demise, despite a promising start: they blew up cop faces.
Only three weeks after the signal was installed, On January 2, 1869, a leaky gas valve caused one of the lanterns to explode, just about blowing the face off the poor bastard stuck there operating the signal.
Disenchanted by the facesplosions, the traffic signal was dismantled shortly thereafter. And Londoners just had to deal with terrible traffic chaos for 60 more years, until they finally got more modern electric traffic lights in 1929.
(Source: The Engineer)