Study finds 405 traffic flowing better over pass

The 405 looking north toward the Sepulveda Pass and the San Fernando Valley. Photo by Steve Hymon/Metro.

The 405 looking north toward the Sepulveda Pass and the San Fernando Valley. Photo by Steve Hymon/Metro.

The new study was commissioned by Metro from Systems Metric Group and is the first to compare traffic flow on the 405 before and after the Sepulveda Pass project that added a northbound carpool lane, rebuilt and widened bridges and on/off ramps and made other key improvements.

The study is posted below along with a summary by Metro staff. The quick takeaways:

The number of Freeway Service Patrol reported accidents has dropped. For example, there were 15 percent fewer Freeway Service Patrol reported accidents in February 2015 compared to Feb. 2009.

The afternoon weekday rush hour now runs from 3 p.m. to 8 p.m. compared to 2 p.m. to 9 p.m. before the project. In other words, traffic is at its most congested for two less hours on weekdays.

Vehicle capacity on the northbound 405 has increased from 10,000 vehicles per hour to 11,700 vehicles per hour at peak times. That’s a 15 percent increase in vehicle capacity and 30-plus percent increase in people traveling on this section of the 405.

Total travel times are slightly lower between the 10 and the 101 except during the peak of the afternoon commute (about 4:30 p.m. to 6:30 p.m.) when travel times are slightly higher. The increase in time, the report says, is due in part to a bottleneck backing up traffic further north at the 405 and 118 interchange.

•Travel times on the NB 405 vary less, meaning travel times are more predictable.

Traffic on major streets near the 405 — including Sepulveda, Sunset, Santa Monica, Pico and Ventura — is 20 to 25 percent lower since the end of construction.

There was a much publicized study that compared traffic on the 405 between Sept. 2013 (during project construction) and Sept. 2014 (after construction ended). The new report was more comprehensive and suggests that while traffic on the 405 is still very, very heavy, the road also seems to be functioning better and is safer with fewer delays due to accidents.

One other note: Caltrans plans to make adjustments to on-ramp meters to the 405 that should also help improve traffic flow.

Here is a summary of the report from Metro staff along with the report, including some charts that you may find helpful:


Here is the news release from Metro:


And here is an economic analysis of the project that Metro commissioned from the Los Angeles Economic Development Corporation:

16 replies

  1. Keep it coming with these ridiculous studies/headlines claiming $1 billion was spent wisely LONG term and then wanting more taxes to widen even more freeways! Dump the Pump Day is this week and Metro itself is spending billions to keep us trapped in our cars in traffic. Which is it Metro, drive more or use transit??? Decide!

  2. $1 Billion to save Motorists 3 minutes per day?

    (“10 hours saved per year”/200 work days per year=0.05 hours per day or 3 minutes)

    I’m so glad the region has its priorities in order!

    • Salami-slicing is an often used technique by government agencies to downplay the issue and they try to sideline the issue by making it sound cheap, all for the sake of wasting it.

      Keep in mind about this, whenever they call for increase in taxes (i.e. retrying for another Measure R extension).

      They’ll use words like “it only amounts to $25 per person per year, it’s only $2.00 a month! It’s less than a taco at King Taco! For not eating one taco, you’d be able to fund it!”

      Yeah, for not eating a taco at King Taco, Metro will waste my $2.00 per month in something ridiculous like another freeway project or going to pay for pension benefits for their union members. I’d rather keep my $2.00.

      • It may not be just “another freeway project” to the many tens of thousands of motorists who use the 405 each day. Unless, of course, you — a very frequent anonymous commenter — believe you are speaking on behalf of all taxpayers.

        Steve Hymon
        Editor, The Source

      • Yes, for those tens of thousands of motorist who continue to spend the same amount of time on the 405 each day, its probably “another freeway project” that did nothing but made their commute worse for half a decade. We know highway expansions never work in the long run due to induced demand, its just surprising that it didn’t do anything in the short run either. That money could have been spent on providing another viable mode of transportation for the region. Obviously not everyone will agree in the implementation of transit but it doesn’t mean we shouldn’t do more to disclose in EIR or in other reports that at-peak this will do little to help and off-peak capacity is less of an issue so the expansion will have little affect overall on your driving experience. Trying to provide a post-project validation when the project under-delivered feels like a poor assessment of the project and doesn’t really help move forward a larger conversation of a transportation system. If the project wasn’t successful telling us why, showing where assumptions were off and providing where some success were is fine but leading with a headline “Study finds 405 traffic flowing better over pass” makes everyone think you are altering data or not tell us the whole story. The report itself shows some of the shortcomings but you have to guys are leading with a headline that seemingly tries to only highlight the “benefits” of the project and honestly its only been a few months of study come back in a year, its almost as bad as the Reason Foundation saying expo line was a failure after opening day, it takes time for travel patterns to change overall but that’s the instant failure at peak is truly interesting.

  3. So now even more people are driving.. And I thought metro was a transit agency? The project was a success!

  4. I had previously also oberved several of the these items.

    Fewer cars stuck in lanes through the pass.

    Much lower travel times / faster speeds, starting as far back as the 90, or further, up to the 101. My NB travel times are generally from ~10 to ~1:30.

    Predictablity of speeds/travel time has increased greatly. Rarely is there a very bad slowdown.

    South bound is also improved through the pass and almost from Roscoe. (Typical travel SB 405 for me is between 6:45 – 11).
    After Sunset SB traffic is soooo very much better than it used to be.

    I was noticing benefits on the NB as soon as new on and off ramps were opening and new bits of the car-pool lane were opened.

    What has become clearer to me is that Roscoe & Sherman Way SB off ramps need a dedicated exit only lane. The shoulder there is wide enough to accommodate it. Also NB Roscoe. Nordoff too prehaps. This would help so many folks at various times of day.
    And to add to that wish list: 110SB Sepulveda and PCH need dedicated exit lanes. I stay to the far left to avoid potential accidents in that area. If I am riding, I advise the driver to do so as well.

    • The data are from 2009 (depths of the recession) and 2015 (booming recovery). So the traffic has slowed, all around town and most times of day. It would be nice to have comparison data for other N/S routes in the county for the same period. I suspect that they would show a larger slow down for the same period.

  5. Santa Monica Bl. traffic is worse than before this project and the one before it in the same area. Grid lock from Centenella eastbound to past the freeway is criminal.

  6. “The increase in time, the report says, is due in part to a bottleneck backing up traffic further north at the 405 and 118 interchange.”

    Wow, this is shameless. You just said that you increased car capacity by 15%, surely it occurred to someone along the way that all that added carrying capacity might mean a “bottleneck” somewhere?

    We spent a decade and billions on a project that is already at capacity. Things are as good as they’ll ever be as a result of this project *right now* and they’re about the same as they were before. BTW comparing two months before and after for safety is not convincing. Somehow I have a feeling that an added lane of traffic didn’t magically turn everyone into safe drivers.

    I guess now we get to wait for Metroto come and ask for money to widen the 405 at the 118 and “fix the bottleneck?” Where does it end? This project is a failure and should only be broadcasted as such.

    • *half of a decade. All though it sure felt like the full 10 if you lived on the westside.

    • If the definition of success isn’t more capacity and less congestion, I’m not sure what is.

    • Scott, the bottleneck is most likely from the construction going on at the interchange, they’re building a cloverleaf, and it only opened recently this year. With that said, the bottleneck up there may have subsided since the cloverleaf opened.