The man who gave us traffic lights
We must thank a Nottingham engineer for making drivers stop and go at busy road junctions.
The next time your smooth drive to work is interrupted by a red traffic light you might reflect on the fact that it was a man from Nottingham who devised the most important system of traffic management.
Engineer John Peake Knight was a railway manager. He specialised in designing signalling systems for Britain's growing railway network. He saw no reason why these couldn't be adapted for use on the road.
A life on the rails
Knight's love of trains dates back to when he was only 12. He dropped out of his Nottingham grammar school and joined his two brothers in the parcel room of the Midland Railway.
Before long he'd left the East Midlands to work in the Brighton area. By the time he was 25 he was Superintendent of the South Eastern Railway.
He continued to rise through the railway ranks until a stroke cut his life short at the age of 59.
The great adaptor
John Peake Knight wasn't really an inventor but he could spot a good idea and use it.
He's credited as being one of the first to introduce emergency brake cords in trains. In 1865 he approached the Commissioner of the Metropolitan Police with an idea to use a railway signalling system on the roads of London.
At the time there were no cars on the road but there was growing concern at the number of horse drawn carriages and danger to pedestrians.
Signalling the way
Knight's proposal was to use a semaphore system - a method where an arm was either in a horizontal position or at an angle. This determined whether a train could pass or not.
The Notts engineer decided to treat main roads and side roads as if they were main and branch railway lines.
The semaphore method would be used during the day and at night red and green lights would be operated instead. These would be powered by gas.
An explosive end
It would take three years before the plan was implemented but on 9 December 1868 the world's first traffic lights were installed at the junction of Great George Street and Bridge Street in the London borough of Westminster, close to Westminster Bridge.
Policemen would stand next to the signals all day in order to operate them.
It was an immediate success. Knight confidently predicted more signals would appear in the centre of London.
But a month into the project disaster struck. One evening a leaky gas mains resulted in one of the traffic lights exploding in the face of the policeman who was operating them. He was badly burnt.
The project, so enthusiastically greeted, was immediately dropped.
A long wait
It would be 40 years before traffic lights reappeared and this would be in America.
They would only become a common sight in London in 1929 when the first electric signals were introduced.
But it was a Nottingham man who had the inspiration.
Spending time in London allowed Knight to see what a disaster the massive amount of traffic on the roads had become. He decided to do something about it. Having spent years developing a number of safety devices for the railroads, he set out to create a signal system that would become known as the J.P. Knight traffic light and is the forerunner of every one of these signals in the world. The first of these lights would be installed near the Houses of Parliament in London in 1868. It was placed on the corner of Bridge Street and George Street, an extremely busy intersection where a number of accidents had occurred.
Unlike the traffic light used today, the invention by Knight had only two lights: one red and one green. The lights were gas powered and only intended for use at night. During the day, traffic flow was to be controlled by two semaphore arms. The premise was simple: If the flag arm was fully horizontal, traffic was supposed to stop. If it was hanging at a 45-degree angle, traffic should proceed with caution. At night, it was even simpler, a red light meant stop, and a green one meant go. The entire system was controlled by a series of hand-operated levers under the control of a traffic officer.
One of the main reasons the city saw fit to maintain a staff of traffic officers was they felt traffic would simply ignore the new system. The officer was responsible for keeping a close eye on the flow of traffic. When he judged it was time to change the lights, he moved the appropriate levers to raise and lower the semaphores. At night, it would be his job to rotate the appropriately colored light to face oncoming traffic. To alert the carriage drivers he was going to change the signals, the officer would give a long blast on his whistle.