Sunday, April 14, 2013

Driving Through Los Angeles Without Even Tapping the Brakes

One of the 4,500 traffic lights recently synchronized in an attempt to keep vehicles moving.

            Los Angeles reached a major traffic milestone earlier this month. The Los Angeles Department of Transportation (LADOT) announced with Mayor Villaraigosa that all 4,500 signalized intersections within the city’s 469 square miles have been synchronized. The synchronization project, which has been in development for over 30 years, is expected to alleviate congestion on Los Angeles streets by reducing delays at intersections and keeping traffic flowing.
According to a Texas A&M Urban Mobility Report, Los Angeles commuters spend more time stuck in traffic than most urban areas, racking up an extra 61 hours a year in their cars due to congestion at the cost of over $1,300 per year, per commuter.[1]

            In order to improve flow on the city streets, LADOT has invested over $400 million into a state-of-the-art Automated Traffic Surveillance and Control System (ATSCS), which monitors and controls the synchronization of all city streets.[2] Many elected officials and transportation engineers alike have praised the system as a tool for mitigating the city’s growing congestion woes, yet the system faces skepticism from members of the community. At the final cost $400 million, some wonder whether the synchronization project is an effective step in the right direction for the City of Los Angeles.

            So what does all this mean for the people of Los Angeles? It depends on who you ask. Elected and city officials are thrilled by the new system, a proposal that has been on the political agenda since the 1984 Los Angeles Olympic games. LADOT boast levels of congestion and delays down 12%, a 16% increase in throughput and a savings of 2 minutes of drive time per 5 minute stretch equating to 2 miles per hour faster.[2] Also cut down is time spent by commuters at intersections. Less time idling also reduces the average commuter cost per mile, as noted above, and reduced levels of carbon emissions by less frequent car stop and starts. Mayor Villaraigosa states that 1 million metric tons of emissions will cease to enter our atmosphere because of the complete synchronization project ( These numbers bolster the system on paper and give Mayor Villaraigosa reason to publicly push the new synchronization technology in conjunction with other transportation improvements within the city.

            General reactions to ATSCS have been lukewarm, at best. Informal public polling has shown that 50% of commuters see no difference while 25% who see a positive change and the rest believe the commute has gotten worse since the switch over.[3] Some attribute the lack in performance to increased driving habits. ATSCS has received a positive reaction from LADOT and Mayor Villaraigosa which could be taken as encouragement of more driving activity by giving a message of “the streets aren’t so congested and traffic is moving, so feel free to drive more!” This school of thought negates the throughput benefit of the synchronization, giving the public an impression of reduced idle times on city streets. Quite possibly, this may be a simple case of “if you build it, they will come” and Los Angeles residents are eagerly taking advantage of any congestion reprieve they can get.

[1] TTI’s 2012 Urban Mobility Report
[2] To Fight Gridlock, Los Angeles Synchronizes Every Red Light
[3] Will Synched Lights Clear A Path Through The City Of Angels?


  1. Downs & Co. would bet us that latent demand will drive traffic flow right back to where it was. Will be fun to check in a few months from now.
    Speeds falling back might not be all bad, either. Pedestrian injury severity increases fast for speeds over 15mph. The linked article reports average speeds on local streets up from 15 to 17.3.

    We're lucky in Portland to have Peter Koonce in charge of signals. Biking around DC this winter, I was shocked at how terrible the signal timing was for cycling. I wonder if LA took bikes & peds into account at all in the plan?

  2. Hey Joe,

    << I wonder if LA took bikes & peds into account at all in the plan? >>

    Actually, the NPR broadcast mentions that cyclists love the new system. From what it sounds like, cyclists are receiving a quasi Green Wave. Apparently, they are cruising through the majority of traffic lights and are the only members of the public that are overwhelming supporting the new system. However, I have not read anywhere in my research on if the system was planned to prioritize cyclists or if it just so happened to coincidentally work out that way.

    NPR also mentioned that buses were having great luck with the new system. I presume it is because they have separate lanes in some areas, so they are able to bypass the line of traffic everyone else is stuck in.

  3. Another interesting news piece I found works at punching holes in the emissions claims by Los Angeles officials. The article, put out by the Atlantic (link below), states that efforts which increase traffic flow "only theoretically reduce emissions." What's their ground to stand on? The same comment we made above: "If you make it easier and cheaper and faster for people to drive, more people drive."

    Although, when I read this it makes me wonder how many people believe that we just shouldn't do anything at all. To that, I say that although signal timing isn't a cure all, it's a least a step in the right direction for fairly inexpensive and logical solutions.


    Additional Reading:
    "Sorry, Los Angeles: Synchronizing Traffic Lights May Not Reduce Emissions"


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