The Slowest Freeway In LA Is Not All Of Them. Here's The Real Answer

(Mae Ryan/KPCC)

Soon, all across Los Angeles, friendly bets will (perhaps) be settled by a group of L.A.-based journalists and data scientists. They say they've figured out exactly which Los Angeles freeway is actually, really, truly, for real, no joke the slowest. And they're giving KPCC/LAist an exclusive on their results.

The project — "The Slowest Road In LA" — is led by Gabriel Kahn and Mingxuan Yue as part of Crosstown — a data-driven effort based out of the USC Annenberg School for Journalism that's looking for new ways to understand L.A., and what it's like to live here.

The team ranked the worst evening and morning commutes. Much like the end of Clue, here's how they did it:

We divided freeways into 26 different evening commutes across Los Angeles County. Then, we analyzed the average speeds on those freeway segments between Feb. 1 and March 25, 2019, by hour of the day and then by day of the week. We then calculated the average speeds during the peak of the evening rush hour (4 p.m. - 7 p.m.) and morning rush hour (from 7 a.m. to 9 a.m.). Learn more about how Crosstown compiles its traffic data here.

While we waited for their big reveal, we asked for your guesses.

Nearly 300 of you responded, with a range of solid hypotheses that included the usual suspect freeways, the 14, the 91, PCH and, sure, the road to your mom's house.

Some of you got it right.


The 5! Heading south from DTLA.

From the study: "The I-405 has its haters. Heading east on the I-10 in the evening can wreck a marriage. But there is one Los Angeles commute that is slower than all others: The I-5, heading south from Downtown in the evening."

On that drive:

  • Traffic moves at an average of 21.5 mph from 4 p.m. to 7 p.m.
  • And it may be getting worse — the average was 23.2 mph in 2017.


  • The 405 heading north where it crosses the 10 took second place at 27.5 mph.
  • The 405 heading south from the 10 came in third at 28.8 mph.


The 405. North from Carson towards the 10.

From the study: "If you commute to work on the I-405, morning becomes apoplectic. Indeed, the 405 holds the title of busiest freeway in the country, an honor it just can't seem to shake... Anyone who struggles with that morning commute might think it couldn't get any worse. Only, it already has."

On that drive:

  • Traffic moves at an average of 24.8 mph from 7 a.m. to 9 a.m.
  • And it may be getting worse — the average was 29.2 mph in 2017.


  • The I-210 heading west from Azusa toward Pasadena took second place at 25.7 mph.
  • The I-5 heading south from Santa Clarita toward Downtown came in third at 35.2 mph.


Morning commutes are usually faster than the ride home — even on the same route. The team says it's in part because people "tend to run more errands (and therefore drive more miles) after work."

Read more about the "LA By The Numbers" at the Crosstown project page.