why aren't the traffic lights in Los Angeles synched up?

This may sound like a gripe but it is really meant as a factual question.

It appears to me from driving in LA (on, for example, 3rd street, Wilshire Blvd, La Cienega Blvd, etc.) that the lights are set deliberately out of synch so you are forced to stop periodically.

Why don’t they synch the lights up so that a car travelling at a set speed will hit each green light? Don’t most major cities synch up their lights this way? Wouldn’t that make traffic in LA flow more smoothly?

Synching lights favors traffic in one direction, and screws it up in the other direction. In addition, lights that are hooked up to detectors will respond to traffic flow, and generally won’t be synched.

It is impossible to synch the lights of one street to both directions at once or to sync a grid of crossing streets. Once you have decided to sync one road you have decided to screw the rest.

As far as big cities synching lights, you should try driving down Peachtree St in Atlanta. You hit every single light no matter how fast or slow you drive.

GTPhD1996

(Survived living in Atlanta during 1996 Olympics)

I think L.A. tries its best to synch its traffic lights, but some of the streets described in the OP pass through different jurisdictions, which probably complicate the matter.

Also, synchronized lights presume that everyone is driving the speed limit. They aren’t synchronized if you are driving too fast

This is true only if the engineers set the synchronization for the speed limit. The lights can be timed for whatever speed they wish. Lakeshore Drive (extending Jefferson out of Detroit through the Pointes) used to be timed to around 37 mph, based on the speed people actually drove in the 35 mph zone. Over time, (with sufficiently intelligent drivers) the fact that the lights are timed will tend to regulate the speed, since people will discover that they “make” more lights at a constant speed and try to match it to avoid stopping. (With a populace containing a sufficient number of stupid people, you will find people racing from one red to the next, then slowing down the paced traffic when the idiots have to begin from a stopped position as the lead cars in the paced group comes up on them just as the light changes.)

When I lived in metro Detroit, I got to know the streets where there were more or fewer idiots, based on traffic flow. I don’t have to “worry” about that around Cleveland, since no highway engineers in metro Cleveland are smart enough to know what a timed light is.

Traffic lights can go out of synch over time and it costs a lot of money to resynch them, money which might be better off going somewhere else.

Starting next month, Cary, NC plans to start synching their 130 lights. They expect the project to take two years with an estimated budget of $10,000,000.