Wider Highways May Not Help Reduce Traffic Congestion In CA, Study Says

LOS ANGELES, CA — It may not come as a surprise that major cities in the Golden State have some of the worst traffic congestion and travel times in the country. But what may be startling is just how ineffectual adding more lanes to highways and roads may be at relieving congestion, a new study indicates.

TomTom, a company that provides global maps and navigation, analyzed traffic data from cities around the world in its annual Traffic Index. The company's analysis of data for 2025 saw less improvement in travel times compared to data from 2024. Nearly 500 cities were reviewed in 2025, and only 34 experienced reductions in their inner-city travel times per kilometer compared to the year before.

Subscribe

Traffic congestion in Los Angeles showed mixed results in the annual traffic index. TomTom's Traffic Index scored cities around the world by congestion level. The City of Angels has a congestion-level score of 59.8, making it the most congested city in the United States. However, traffic flow still moves quickly in Los Angeles. By travel time per kilometer, L.A. ranks #385 in the world, making it one of the fastest moving cities in TomTom's latest report. In free-flow conditions, it takes motorists 58 seconds to travel one kilometer. In traffic, that number increases to 1 minute 33 seconds.

TomTom's study also indicates Los Angeles has a highway kilometer ratio of 63%, which means more than half the roads in the city center area are highways, and the average highway speed is nearly 37 mph. It's not surprising that travel times remain high. The roads are susceptible to congestion, suggesting that building more high-speed roads won't solve congestion,the TomTom study said.

"The most congested cities in the world, by congestion level, might not be the slowest in absolute terms. But they may be just as, if not more, frustrating for drivers on the ground every day, as they are the cities that slow down the most as traffic fills up their streets," according to TomTom.

Traffic in Northern California's most populated city is similar. San Francisco was among three U.S. cities where travel times worsened last year, including Syracuse, New York and Minneapolis, Minnesota. San Francisco saw its traffic times increase by 6.6 percent. San Francisco motorists spent an additional 11 seconds in traffic.

"For more than 15 years, the TomTom Traffic Index has monitored the health of our roads, capturing its minute-by-minute pulse to assemble a year-long overview of how vehicles have moved through hundreds of our world's major cities. This year's edition tells a painfully familiar story. As cities grow and journeys multiply, the challenge of managing city road networks continues to loom over municipalities, town planners and transit authorities," TomTom said in the report.

"As people flock to cities never designed to house such vast populations, traffic will continue to worsen unless cities act now, arm themselves with the right data and the most useful and trusted insights."