When is LA traffic the worst?

That depressing statistic comes from latest annual report by INRIX, a Washington-based traffic research company. INRIX not only ranks the country’s worst traffic cities each year, but also lists the worst times to drive in those cities. So what’s the worst hour of the week on LA’s traffic-choked streets and freeways?

The most congested hour in LA each week is 4 p.m. to 5 p.m Fridays. That’s according to Jim Bak, communications director for INRIX and one of the authors of the report.

Bak’s data is based on real-time traffic updates from drivers using smart phone apps, GPS trackers attached to fleet vehicles, and freeway road sensors — to name just a few of the more than 100 pieces of data INRIX took into account to arrive at something called the “delay index.” That’s an estimate of how much extra time it takes get around every day because of traffic jams, compared to how long it would take if the roads were clear.

But not everyone agrees with INRIX’s verdict. Edward Yu, a transportation engineer for the city says that the worst days of the week are usually Tuesday, Wednesday and Thursday. “A lot of people are off on Mondays or are off on Fridays, so those are usually your lighter traveling days,” he said.

To get to the bottom of this traffic conundrum, we talked to drivers, and our own resident traffic expert, Kajon Cermak.