PORTLAND, Ore. (PORTLAND TRIBUNE) — Portland is tied with Chicago and Washington DC for the eighth most congested metropolitan region in the country, according to a new study by Tom Tom, a navigation system manufacturer that also analyzes traffic conditions.

The TomTom Traffic Index found that all three cities had an overall congestion level of 26 percent in 2015, meaning the extra travel time on both highways and non-highways anytime of the day compared to what should be free-flowing conditions. The 2015 Tom Tom Index was released Tuesday.

Nick Cohn, Tom Tom’s senior traffic expert, was surprised Portland rated so high, considering the city’s reputation for alternative transportation, like MAX trains and bicycling. But after analyzing traffic patterns in the metropolitan area, Olsson says much of the congestion is caused by people commuting to employers outside Portland, like the high tech companies in Hillsboro, like Intel.

“MAX is set up to serve Portland, not the employment centers in the surrounding communities, that are also too far away to bike to,” says Cohn.

According to Cohn, so-called reverse commute patterns are difficult for governments to change because they are caused by people making personal choices about where they want to live and work. For example, Intel employees may prefer to live in the Pearl District in Northwest Portland, despite the commute.

You can read the 2015 Tom Tom Index here.

Cohn’s comments are consistent with a survey released on March 16 that ranked seven Portland highway corridors among the most congested in the country. The INRIX traffic study identified two of them as connecting Portland and Washington county. They are US-26 from Camelot Court to Canyon Road/Exit 73 and OR-217 from the 72nd Ave/Exit to the Hall Blvd/Exit.

But the INRIX survey identified congested corridors in the rest of the metropolitan areas as well. The remaining five are: I-5 from 43/Macadam Ave/Exit 299 to N Tomahawk Island Dr/Exit 308; I-84 from OR-99E/Pacific Hwy/Grand Ave to 1-205/Exit 8; I-205 from Washington St/Strark St/Exit 20 to US-30 BUS/Columbia Blvd/Exit 23; and I-5 from Hanes St/Exit 293 to Elingson Rd/Exit 286.

According to the survey, “Urbanization continues to drive increased congestion in many major cities worldwide. Strong economies, population growth, higher employment rates and declining gas prices have resulted in more drivers on the road — and more time wasted in traffic.”

That conclusion is consistent with a local report released by the Value of Jobs Coalition that concluded increasing traffic congestion could cost the Oregon economy almost $1 billion annually by 2040, with most of the increasing expenses occurring in the Portland area.The Portland Tribune is a KOIN media affiliate.