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: