William Phelps Eno’s Rules of the Road

This is a post prompted by questions from Ms. Sawatdeeka about traffic flow and traffic rules. Where did the rules of the road come from? Our story begins in New York City in the 1870s. A nine-year old boy was riding in a carriage with his mother and they got caught in a traffic jam. Horses had to be backed up with a wagon and another carriage, and an hour was spent sorting things out before anyone could proceed.

That was typical for any city and had been the way of things for centuries. People would go the best way they could. Traffic was a problem wherever you went, but at the speed of horsedrawn carriages and wagons, crashes were rare.

That traffic jam really impressed young William Phelps Eno. He thought about the problem many times over the years. His father and his mother’s father were both growing wealthy in real estate, and after going to Yale he joined the family business and prospered.

When he was forty years old, in 1900, Eno published an essay about his proposal for rules of the road. He said that if the rules were simple, easy to understand and follow, and were enforced, that movement on all city streets could be improved.

He provided such eloquent arguments and the problems of traffic congestion were so severe that his proposal quickly was circulated among the city fathers. They decided to adopt Eno’s proposed rules of the road as an ordinance. After much debate and a flurry of articles in the newspapers, the rules of the road were implemented in 1903.

It was an instant success. In fact, it was so successful that people were amazed at the difference it made in the time it took to go a few blocks through the city. Stop signs were an innovation of the rules of the road. Everyone driving on the right side of the road, with faster traffic passing on the left, were innovative. City life was much improved.

Eno’s proposed rules adopted the general practice of driving on the right. That had been general practice for a very long time, lost in the dim mists of the past, but it had never been law, except on a few toll bridges.

To that, Eno added the stop sign. If you are on a minor street, you have to yield to the traffic on the major street; you don’t get to dart out and jam your way into the traffic flow. Pedestrians have to wait until there is a gap, but then once they get out into the street, carriages or cars have to yield to the pedestrian. If you are going to park so you can load or unload at a business, you have to be parked in the direction of travel on the right.

The improvement was so dramatic that visiting Frenchmen begged Eno to present his scheme to the Académie Française. Paris hosted a demonstration project at the Arc de Triomphe in early 1905, and adopted Eno’s rules of the road later that year. Soon, the rules of the road were being implemented all over the world, including lots of places that never bothered with formal adoption.

One of the graybeard professors who taught traffic to me in the 1970s said that when the British adopted the rules of the road, of course they chose the opposite side, because they were not going to do anything the French and American way. But I have seen historians say that keeping left was an old British tradition, and that it was the Americans who switched the pattern. (Evidently, the way a Conestoga wagon was constructed lent itself to keeping right, on account of the location of the brake lever, and this was in imitation of earlier carriage designs, so that passing on the right had been an old tradition in America. But it had not been a rule, just the common way things were done.)

Eno’s simple project brought order into the chaos of traffic just in time for the motor age. I do not see how the automobile could have flourished as it did without the rules of the road. The 1908 Model T was built with the driver position on the left, and American cars from all other manufacturers soon followed suit.

Eno continued to develop his ideas and wrote subsequent papers. He wrote a bulletin for police enforcement. He wrote a paper about harbor traffic. In 1921 he made a grant to set up a foundation to work to improve traffic safety. The Eno Transportation Foundation still works to improve traffic safety. They moved their headquarters to a suburb near Washington, D.C. about thirty years ago.


5 thoughts on “William Phelps Eno’s Rules of the Road”

  1. I never thought Bubba would be accused of trafficking but this post is all about that.

    In Japan the stop signs are usually triangles but there is a round one for railroad crossings.

  2. Yes, there is some variety of sign shapes in different parts of the world.   I think the round sign got claimed early by the railroads globally.

    I don’t know, but my guess is that Japan adopted British style by observing how dramatically it improved life in Hong Kong.


  3. MJBubba:
    I don’t know, but my guess is that Japan adopted British style by observing how dramatically it improved life in Hong Kong.

    Probably more because Japan was strongly Anglophilic in the period from 1870-1920. They copied the British in everything, except their army (where they copied the Prussians, more is the pity).


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