SR 516 is the only other State road within the City that carries a significant number of vehicles; however, SR 516 has the capacity to carry additional traffic. Currently it is carrying 60 percent local and 40 percent through traffic.

Previously permitted subdivisions with single entrances compound the congestion on both roads. If this type of development continues to be permitted, the congestion will increase more rapidly than with a development code that requires multiple entrances and exits to subdivisions, creating a grid network.

According to the Maple Valley Planning Assistance report, the number of homes that could be constructed within the City 3,900. According to the Institute of Transportation Engineers Trip Generation Manual each household generates approximately 10 trips per day. Therefore, these additional 3,900 homes will generate approximately 39,000 vehicle trips per day, or 3,900 vehicle trips per hour. This number of trips is greater than the current number of trips on SR 169, SR 516 and Witte Road. These numbers are based on national averages for trip generation per household. However, with the current development pattern, and based on what we have heard about driving patterns in the City, this trip generation rate is low. Other communities have been know to approach 20 trips per day per household. If this figure is low for this area and 14 is a more realistic figure then the City faces the prospects under current conditions of having to widen SR 169, SR 516 to six-lane roads and Witte Road to four lanes. In addition, if there is a large increase in development outside of the City then even these roads will be inadequate.

Improvements to the function of a road system typically occurs through a combination of trip reduction methods, such as changing development patterns, and built transportation projects, such as widening roads and adding transit services. The City has two primary options available in the short term, and several others for the long term.

1. Increase capacity of Maple Valley Highway by improving SE 231 ^st Street, its interchange with SR 18 and its intersection with Maple Valley Highway.

• Roundabouts at each of the intersections.
• Full pedestrian facilities, i.e., sidewalks, trees, and pedestrian level lighting.
• Bicycle lanes (even if they are currently discontinuous).

As Facilitated and Recorded by Walkable Communities, Inc.
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E-mail comments to Gregory J. McCormick
       AICP, Director of Community Development.