To Fight Gridlock, Los Angeles Synchronizes Every Red Light

Perhaps a cheaper model could simply tie light timing to average speed; without all of the data input.

One advantage of the cheap model would be that the drivers become accustomed to a "target speed;" knowing that the target speed optimizes the stop and go cycle.

Reducing the number of commuter stop and go cycles will have significant effect on energy use and thus air pollution; especially with the low efficiencies inherent in reciprocating engines, where each unit of Kinetic energy conserved through reduced braking or regeneration translates to some multiple of fuel combustion energy savings.

Since such a large portion of electrical grid energy comes from combustion fuels; even the efficiency of energy use by electric vehicles increases; with a corresponding decreases in combustion energy requirements at the grid source.

The down side to the LA system is cost and complexity. Is it possible that at some point the increasing data influence on light timing would become counter productive - reducing throughput?

Again, a simple target speed system might make traffic signal sequencing more affordable and thus more widely applied than the centralized complex algorithm based LA system.

Also; how does the square relationship of speed to kinetic energy relate to safe braking distance? How does this impact throughput?

That was the system they used in St. Petersburg, FL, when I lived there a number of years ago for a pair of miles-long one-way avenues, 1st Ave N and 1st Ave S. (It may still be that way.) The problem was some drivers want to go a few miles above and some want to go a few miles below the speed limit. After just a few intersections the pack of cars was spread out and the faster cars started arriving too soon at the next light and had to brake, causing everyone behind them to brake, sending a wave of slowed cars back through the pack, and the slow cars were met by the faster cars in the next group... Just never worked. It was maddening being the 'lead' car going exactly the speed limit and have some knuckleheads pass me, swerve in front of me, then have to brake ...

You just can't fix stupid.

I like to see that algorithm to balance that out.

Unfortunately they were synchronized to "It's Raining Men" and traffic has come to a complete standstill....

They didn't achieve anything like that. Even on a single two-way road, it is impossible to get uninterrupted traffic flow, unless certain light spacings versus vehicle speed conditions obtain.

Its a great idea, but Los Angeles is not (by a long, long way!!!) the first to do this.

West London was computerized in 1967!!!! YES 1967!!! NO MISPRINT!! (I believe this was the first time for London.(Open to correction on this point!)

Using if I remember correctly, then GEC Computers.(Open to correction on this point!)

This was quickly spread to the whole of London.

In 1979, Sperry Univac replaced the (now) old GEC Computers with many "mini" computers, using RS232 to communicate to the local controllers. I remember we replaced GEC computers....

These controllers, if they lost "contact" to the mini computer, could work independently, on a best effort system, till contact was re-established.

They were fed data on day of the week, time of day, direction need for maximum traffic etc etc....

I am sure that the Sperry systems have long been replaced, probably several times over since I was last involved.....

The population of Metropolitan London is over 13 Million since 2001.

London's metropolitan area is about 600 square miles.....see here:-

London

So not only has London been computerised for traffic control probably longer than any other city in the world (first traffic light 1868! But without either electricity or computers!), but its also probably the largest urban metropolitan area that has traffic control from computers as well.

Dream on Lost Angeles......