Growing population, shrinking streets: A very Portland formula for traffic congestion

It’s not an illusion. Portland traffic is getting worse: Longer drive times, more congestion, angrier drivers, and “active transportation” that should be renamed “aggressive transportation.”

And, it’s no accident. It’s all part of the City’s Vision Zero plan for transportation. One consequence of Vision Zero is that while Portland’s population is growing, its street network is shrinking.

Miles go missing on Portland streets

In a Friday afternoon bad news dump, the Portland Bureau of Transportation revealed (PDF) that the city’s streets have deteriorated over the past year (more on that in another post). The miles of unpaved streets and streets in “poor” or “very poor” condition have increased by 3 percent since last year.

But that’s not the big story.

The big story is that since 2010, 77 miles of Portland streets have disappeared.

In 2010, PBOT reported (PDF) the City had 4,907 lane miles of improved streets and 60 miles of unimproved streets, for a total of 4,967 miles of streets.

The most recent PBOT report (PDF), for 2014, shows 4,834 of paved streets and 56 miles of non-paved streets, for a total of 4,890 miles of streets.

Between 2010 and 2014, 77 miles of streets have gone missing. That’s a drop of 1.6 percent.

And it gets worse …

Over that same time period, Portland’s population has grown by 3 percent (that’s about 18,000 more people in the city).

Put those two things together: Portland has gained 18,000 more people and lost 77 miles of streets. That means that for every 230 people Portland gains in population, the city’s street network loses 1 mile.

One would think that the city would increase the capacity of it’s street network in response to a growing population, rather than shrink it. But that’s not the point of Vision Zero.

On the upside, we have made some progress toward explaining why Portland’s traffic congestion worsens by the year: More people, fewer streets.