You don’t have to be a Blue Origin rocket scientist to see that Seattle has a serious traffic problem. The city’s streets are flooded with cars, buses, and cyclists during rush hour every day and it’s even becoming difficult to get around on weekends. Officials are working on solutions to the city’s transportation woes, but they can’t progress fast enough to keep up with the population boom, driven largely by job growth in the tech sector.
A new study from Kirkland, WA.-based transportation data firm, INRIX, ranks Seattle sixth on its list of the nation’s worst cities for traffic. The Transportation Scorecard claims that, on average, Seattle commuters spend 66 hours per year sitting in traffic.
That number might sound about right if you’ve ever been caught on Mercer at 5 p.m., but some argue studies like this don’t tell the whole story. A similar report, published by INRIX and the Texas Transportation Institute last year, received criticism for failing to consider suburban sprawl in its methodology.
Here’s what David Alpert, founder of Greater Greater Washington and former Google Product Manager, says about these transportation studies:
Consider two hypothetical cities. In Denseopolis, people live within 2 miles of work on average, but the roads are fairly clogged and drivers can only go about 20 miles per hour. However, it only takes an average of 6 minutes to get to work, which isn’t bad.
On the other hand, in Sprawlville, people live about 30 miles from work on average, but there are lots and lots of fast-moving freeways, so people can drive 60 mph. That means it takes 30 minutes to get to work.
Which city has worse roads? By TTI’s methods, it’s Denseopolis. But it’s the people of Sprawlville who spend more time commuting, and thus have less time to be with their families and for recreation.
In both the TTI report Alpert references and INRIX’s new Traffic Scorecard, speed is the primary factor considered. INRIX researchers measured the average time spent on road segments during 15-minute intervals in peak travel hours. They then compared that data to the “reference speed” or the time it takes to travel those road segments when not congested.
“INRIX did not calculate average distance between specific drivers’ homes and offices for this report (the data INRIX collects is anonymized), but rather converted delays from a typical commute trip into monthly and annual delay totals or ‘hours wasted in congestion’ by estimating the typical commute trip length (in time) and the number of trips the typical commuter takes in a month/year,” said an INRIX spokesperson.
Using that methodology, INRIX found that commuters spent a total of over eight billion extra hours stuck in traffic, nationwide, in 2015. INRIX conducted the study to show that while job growth and low gas prices are a boon for the economy, they take a toll on our nation’s urban centers. The Traffic Scorecard provides important data for understanding congestion but, as Alpert notes, there are many dynamic factors to consider when measuring the transportation efficiency of our cities.