With fall beginning and rain becoming more frequent, the Seattle Department of Transportation is winding down its annual preventative maintenance and street paving programs that require dry weather. Microsurfacing and crack sealing are the processes that are the most weather sensitive.

SDOT completed its second ever microsurfacing project this summer in the Arbor Heights neighborhood of West Seattle covering 26.8 “lane-miles” of residential, non-arterial streets. (A lane mile is one mile of a standard traffic lane.) Microsurfacing is a preventive maintenance treatment consisting of applying slurry of crushed stone and asphalt emulsion. This technique extends the life of pavement that is in good condition and keeps lightly traveled streets from deteriorating to the point where they require major rehabilitation. Before SDOT began microsurfacing, crews chip-sealed these streets, a process that leaves troublesome loose rock for a period after the work is done.

Crack-sealing is another roadway maintenance process that requires warm, dry weather. This summer SDOT sealed cracks and joints on nine arterial streets in south Seattle. This work prevents water from seeping under the pavement causing potholes and other roadway damage.

Street paving continues year-round when the weather allows, although long stretches of dry weather in the summer provide the opportunity to complete more work than during wetter seasons. At the close of summer we have accomplished much of this year’s work:
· Near completion of 17.4 lane-miles of a major paving and street improvement project on Holman Road Northwest, North 105th Street and Northgate Way. The contract for this project also included paving along the First Hill Streetcar route in the Chinatown International District and Capitol Hill neighborhood.

· Arterial asphalt and concrete spot paving completed by SDOT crews at 58 locations totaling 13.6 lane-miles. The target by year-end is 16 lane-miles.

· Non-arterial asphalt and concrete paving completed by SDOT crews at 45 locations totaling 4.8 lane-miles. The target by year-end is 4.9 lane-miles.

Seattle’s street network consists of 1,547 arterial and 2,407 non-arterial lane-miles of roadway pavement.