Prior to 1 Jan 1980, most of the country did not have "Right Turn on Red". This meant that if you were stopped at a traffic light, you had to wait for the light to turn green, whether you were going right, left, or straight. California and a few other western states, however, allowed you to treat a red light as a stop sign, provided you were turning right (or left onto a one way street from a one way street). In other words, come to a full stop, check for traffic, and then proceed when it's safe. During the OPEC oil embargoes of the 1970s, a few states experimented with this and found a noticeable improvement in gas mileage, and the federal government tried to pressure the rest to join in, but many refused, claiming it wasn't safe. So starting on the 1st of January 1980, every state in the country was mandated to adopt this rule. Was it safe? For the first few years, there were on average 84 fatalities a year involving such intersections. This is a small enough number on the scale of traffic fatalities (about 40,000 a year) as to suggest it was never really a problem.
(I happened to be living in Massachusetts when the change was mandated. Many right turns, such as ones that cross another street, are not safe to do this on, so signs that specified "No Turn on Red" could be placed at such location. On New Years Eve 1979 (it was a monday), essentially every traffic light in Massachusetts gained such a sign. There weren't many state highway workers leaning on their shovels that day. The feds caught wind of this and made them take about 90% of them down.)
The traffic flow efficiencies come not from idling less, but from more cars being able to make it through the intersection over a given time. If, say, 20% of cars don't have to wait for the light, that's 20% less time the light needs to be green to allow the same number of cars through. That means the chance of cars on the cross street having to wait for a red light are reduced by that much.
One consequence of this notion about right turns is that many traffic engineers haven't quite grasped the idea that a busy intersection needs a dedicated right turn lane in order to gain the traffic flow efficiencies. To some degree this is understandable: when many streets were built, they weren't all that wide, and buildings were placed close to the right of way. If there's only room for one turn lane, they chose to make it a left turn lane because those cars actually do have to wait for oncoming traffic...the right decision.
But there are lots of places that they have the room and in surprisingly many they have actually gone out of their way to block it. There used to be a right turn lane in the picture to the right, but they actually added the little bumpout about 5 years ago to block free rights. Are they thinking they're protecting the crosswalk? That's a bus stop just to the east--but why shouldn't cars use it when buses aren't?
To their credit they are fixing some: this intersection in Ballard,
which I go through almost every week, was improved a few months ago: That
maroon car is parked, the front car in the eastbound right lane is going
straight, and probably half the cars waiting behind are turning right, so they
are stuck. Since this picture was taken, about 4 cars of parking have been
converted to right turn only lanes. It's still got looonnnnng
lines, but it's a huge improvement.
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