Stephen Rees's blog

Thoughts about the relationships between transport and the urban area it serves

The yield to the right concept

with 7 comments

Not politics, but traffic regulation. And one of my hoby horses. A letter appears in the ITE Journal this month that is worth repeating here as it introduces information that I was not previously aware of. The author is Kenneth Todd, and while I do not have his permission to reproduce it I think he will be pleased that this idea is promulgated.

The yield to the right concept originated in France. Charles-Marie Gariel, a professor of physics at the School of Highways and Bridges, proposed it in 1896 as a rule when two cyclcists arrived at an intersection at the same time (source: Gariel, Charles Marie. “De la Règle à adopter en cas de Rencentre sur deux Routes qui se croisent” Revue Mensuelle du Touring-club de France July 1896 pp. 246-247) The rationale was that the cyclist on the left had no need to stop or slow down too much when yielding to the one on the right. Gariel only considered the conflict between two cyclists, not three or four.

Paris, France adopted the rule in 1910 for intersections where two roads of equal width met, and another rule gave drivers on wide roads priority over those on narrower ones. The League of Nation’s International Convention relative to Motor Traffic adopted the rule in 1926, as did the US Uniform Vehicle Code. It remains valid in all US states and by international convention in all countries where traffic drives on the right side of the road.

As William Phelps Eno, the American “father of traffic control,” and others pointed out in the 1920′s, the rule paralyzed traffic when drivers entered an intersection from all directions and obstructed others from leaving. (sources: Eno, William Phelps Simplification of Highway Traffic Saugatuck CT USA Eno Foundation 1929 p.15   McClintock, Miller Street Traffic Control New York NY USA: McGraw Hill 1925 pp 126-127  Lefferts, E B “Giving Man on Left Right of Way” National Safety News December 1922 p40) The rule is rarely in force today, but it shows that early law-makers lacked the most elementary understanding of the intersection problem. Reversing the rule so that the driver on the right gives way to the one on the left would make an intersection function like a mini-roundabout and avoid the installation of countless traffic signals.

The problem is that the ITE Journal is not read outside of the profession – you have to be a Member to get hold of it. I doubt that it is in many public libraries. So I am taking this bold step of doing more than a brief quotation in the hopes that this idea will spread.

Written by Stephen Rees

August 26, 2008 at 3:38 pm

Posted in Traffic

Tagged with , ,

7 Responses

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  1. Nice urban legend.

    I beg to totally disagree. The whole concept comes directly from the navigation “Rules of the Road” and specifically the British Admiralty from well before the days of Nelson. A British Man of War had a small veranda usually on the right side (Starboard) of the ship for the Captain to have a little privacy. Because of its location vessels maneuvering were required to yield (“give way” in today’s terms) to those on its right (where the Captain, pacing about on his private little porch would be expected to see them). Today ships display a green light on their starboard side indicating to other ships that they can expect the ship to give way in that sector. (At night if you see green you maintain your course, the vessel displaying the green light should give way to you.) The Port or left side is red for the same reason, the vessel is now the “stand on vessel” and others are expected to give way in that sector. And those green and red navigation lights date from the Nelson period as well.

    The same principle was our course adopted for roads, no matter what the means of propulsion. Many of our other traffic laws can also be traced to our maritime heritage.

    Actually we’d do well to emulate more maritime laws and conventions on our roads. First rule of navigation? — “tonnage wins”, think about that when challenging a large truck for space on the freeway. Also in maritime law anyone involved in a collision is held to be responsible to some degree since Rule 2 requires the seaman to do anything necessary as to avoid a collision even if it requires deviation from the rules. Admiralty courts don’t have to fix blame, only percentage of fault. Keeps all the ship masters on their toes!

    Aboard the sailing vessel JoVanna in cloudy Seattle.

    Garrison Bromwell

    August 26, 2008 at 5:16 pm

  2. I do not think that urban legends come with references or citations! If you can find some evidence to back your assertion, I will write a letter to the ITE Journal and pass that along!

    Since the British drive on the left – which all of Europe did until Napoleon made everybody switch, just because he could – they do not have this ridiculous rule. In fact they have lots of roundabouts which sensible American traffic engineers have been trying to get silly Americans to adopt for years, but are stymied by this silly archaic rule.

    Moreover, while green to green may work on the open seas as a way for oncoming ships to pass each other when travelling in opposite directions, in confined quarters that “rule” does not apply. Skippers talk to each other on the marine radio and agree how to pass – and how to overtake, depending on conditions. I have to monitor Channel 74 every night and listen to them negotiating.

    And by the way the first rule of the sea is that steam yields to sail!

    Stephen Rees

    August 26, 2008 at 6:47 pm

  3. Even human-powered boats yield to sail too.

    Ron C.

    August 27, 2008 at 12:35 pm

  4. But sailboats yield to tugboats towing barges.

    Sungsu

    August 27, 2008 at 1:19 pm

  5. That’s probably a practical matter regarding stopping distances and momentum.

    Ron C.

    August 28, 2008 at 3:16 pm

  6. Barges do not stop – if the tug stops the barge runs them down!

    Stephen Rees

    August 28, 2008 at 3:29 pm

  7. Hello.

    May I ask some question about traffic?

    Could tell me what off-side priority rule and on-side priority rule are??

    john bang

    April 28, 2010 at 6:21 am


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