The Bad News About Improving Traffic

As Stimulus Money Dries Up, Speed Improves

Tim Lloyd

Nestled within the river of red brake lights that defines Los Angeles freeways are a few spots where traffic has actually improved over the past few years. There aren’t many of them, and the reasons why cars are travelling faster in these places isn’t exactly cause for celebration. But they do buck the overall trend of heavier congestion, longer commutes and slower speeds.

Take the I-405 along the dreaded Sepulveda Pass. A 2015 study by the American Highway Users Alliance listed two commutes here among the top-five most congested roadways in the U.S. But in 2009, California was able to snag $6 billion from the American Recovery and Reinvestment Act for transportation projects. The state Department of Transportation, or Caltrans, devoted $1.6-billion to the Sepulveda Pass Improvement Project, a 10-mile carpool lane intended to improve one of the country’s most nightmarish stretches of freeway.

The SPIP was plagued by longs delays and cost overruns that saw the Metropolitan Transportation Authority surpass its original budget by 55 percent. Until its completion in May of 2014, the project flummoxed L.A. motorists with poorly advertised ramp closures, detours, and construction that frequently blocked lanes.

But when the crews finally finished their work in 2014, and the new carpool lane opened, traffic began to accelerate. In 2016, the average speed rose by 7 mph on the 6.9-mile stretch, running from Venice to Getty, on the 405 North during the morning rush.

That’s quite an outlier. Average speeds around freeway interchanges – typically the worst trouble spots – between that same time slowed by 25 and 50 percent. But the improvement on the 405 might have more to do with simply the end of the intrusive construction project than any lasting improvements brought by the carpool lane.

An extensive analysis conducted by ((insert our link)) University of California’s Integrated Media Studies Center and the Annenberg School of Journalism found eight spots along Los Angeles freeways where speeds have picked up over the past four years. The problem is, most of those same spots are where a major construction project concluded. And so the improvements might be more the result of the reopening of an area that had been plagued by the interruptions that accompany major earth-moving and paving work in general.

͞There was a lot more construction than normal͟ during that period, says Jean Matute, an associate director at the UCLA Lewis Center and Institute of Transportation Studies. Much of that, he adds, stems from the massive American Recovery and Re-investment Act. All of that money led to a ͞large increase in capital funding for highways and funded a lot of projects in Los Angeles County.

As that construction cleared, so did the traffic. But it’s difficult to quantify whether the projects actually brought lasting benefits. For one, traffic generally improved during the Great Recession because so many people were out of work (unemployment in the county spiked to over 13 percent in 2010) that fewer commuters were on the road. The data in our analysis covers the period from 2012-2016. In that period, the economy surged (unemployment is now at 5%) and many of these nettlesome construction projects finally wrapped up. Los Angeles County addednearly 470,000 jobs since the recessionary trough of 2010, along with 771,500 new vehicle registrations in the past six years, according to the Department of Motor Vehicles.

For example, average rush-hour speeds from Puente Avenue to Del Mar Avenue along the I-10 increased to 36.19 mph, or by 4.3 miles per hour faster than 2012 rates. In 2013, construction workers completed a 14-mile long, bidirectional toll road there called the Metro ExpressLanes Project.

On the I-5 freeway, traffic relief also coincided with the end of some major roadwork that had been going on since 2011. In addition to multiple bridge and road repairs, the I-5 Major Improvement Project also added two new lanes just south of SR-91 in 2014, expanding total capacity to 10 lanes.

In 2016, the average southbound speed along the 14 miles from south of Wabuska to Sheldon Avenue during the morning rush hour rose by nearly 4 mph, to 53.9 mph, over the average 2012 speed.

Resolved I-5 Improvement project initiatives also improved traffic flow on the Northbound commute from Silverbow Avenue to South of I-710 by 3.18 mph. Further, the drive from Imperial Avenue to Westbound Anaheim on the I-710 South sped up by over 8 mph in 2016. That is the area where the I-405 Improvement Project clogged freeway interchange arteries during the construction phase. The work ended in 2014.

Caltrans Office of Traffic Design Chief Homar Noroozi , when presented with the findings of the study, said that the end of road construction doesn’t tell the whole story of why traffic improved. He said emphasis also should be placed on enhanced freeway capacity as a contributing factor in the apparent improvement of traffic flows and reduction in congestion.

According to Noroozi, improved lane capacity on the 405, the 5 and 10, may reduce the bottlenecks caused by the average 400 incidents and accidents per day. These non-recurring, or unique incidents, account for half of all freeway congestion in the region.

But, lacking more detailed data and analysis, Noroozi said, Caltrans is not in position to draw specific conclusions.