Potholes, broken or cracked pavement, rutted lanes. These are some of the ailments that afflict Seattle's roughest arterial streets.
A recently completed Seattle Department of Transportation assessment found that about 36 percent of the city's 490 miles of arterials were in some form of poor condition last year. That number is up from 26 percent in 2010 and is higher than any other year SDOT has evaluated since 2003. The proportion of city arterials in the worst shape more than doubled between 2010 and 2013.
The costs associated with undone repair work are also stacking up. Back in 2010, the amount of money required to take care of SDOT's backlog of deferred paving maintenance totaled just over $570 million. By last year, the figure had ballooned to about $900 million.
The explanation for the growing backlog is simple enough.
"The rate of deterioration of the pavement is exceeding what we're spending on repairs," said Elizabeth Sheldon, SDOT’s Director of Street Maintenance.
The percentage of Seattle arterial streets in seriously poor or failed condition more than doubled between 2010 and 2013. Source: SDOT
The city's budget for its two major paving programs was $17.9 million in 2013 and $16.1 million in 2014. In both years, SDOT allocated an additional $2 million for pothole repairs. Since 2007, the city's voter-approved Bridging the Gap levy has funded most of the city's major repaving projects. While repair needs have still outpaced maintenance efforts, the levy has helped to keep street conditions better than they might have become.
The city's Arterial Asphalt and Concrete Program, which involves major paving projects, has been largely funded with money from the Bridging the Gap levy since 2007. Source: SDOT
At the end of next year, the funding measure is set to expire.
"I anticipate we will have to go to the voters again," Tom Rasmussen, who chairs the City Council's Transportation Committee, said last week as he discussed the $365 million property tax levy. "It really has filled a huge need."
Rasmussen, who is also on the Bridging the Gap oversight committee, added that he would be comfortable telling voters "you've trusted us with this money and here's what we've done."
The city's arterials deteriorated even as overall traffic declined. SDOT estimates the average citywide traffic volume each year using vehicle counts taken at 19 bridges. Between 2006 and 2012, the average amount of daily vehicle traffic went down by about 7 percent, based on these estimates. But high traffic volumes are not the only contributor to wear and tear.
"There are certain vehicles that put tremendously heavy loads on your roadways," said Larry Galehouse, director of the National Center for Pavement Preservation at Michigan State University. He noted tractor-trailers and garbage trucks, as well as buses, which are a primary mode of mass transit in Seattle. "It really accelerates the wear."
Galehouse said that a rough rule of thumb is that one loaded tractor-trailer can cause the same amount of road wear as approximately 9,600 automobiles.
Some of Seattle's older streets were not designed to handle those types of loads.
"A street built in the 1920's, no one anticipated the size of the buses that would be on it now," said SDOT's Sheldon.
Seattle is not the only city dealing with rough streets. Last October, a nonprofit research group called TRIP, ranked urban areas based on the share of their roadways in poor condition. Seattle was near the middle of the pack, according to the group, which is sponsored by insurance companies, equipment manufacturers, construction firms, and other organizations with ties to the road-building industry.
Among 20 metropolitan regions with more than 500,000 people, Seattle ranked 12th, meaning that eleven of the other cities TRIP ranked had a higher proportion of streets in bad condition. TRIP's analysis relied on 2011 Federal Highway Administration survey data and included not only locally maintained streets, but also state roads running through each urban area. A report the group issued earlier this year estimated that driving on rough roads costs the average Seattle motorist $625 annually in extra vehicle operating expenses.
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