12/15/98 Public Works Committee - Laserfiche WebLink

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PW CASE REQUEST FOR STOP SIGNS AT 144TM LANE AND TUNGSTEN WAY By: Steven J. Jankowski, City Engineer Background: This case was originally placed on the November 17, 1998 Road and Bridge Committee agenda, however the petitioner could not be present. On November 4, 1998, the City received a letter from Shelly Peterson of 6140 - 144th Lane NW, requesting that stop signs be installed at the intersection of 144th Lane and Tungsten Way. Her letter is attached to this case. In accordance with the policy for processing such requests, the staff traffic review committee consisting of the Police Chief, the Director of Public Works, and the City Engineer, met to review the intersection on Friday, November 13, 1998. Attached is a report on the conditions observed and the accident history background and the staff's recommendation. Site Distance: The intersection was viewed for site distance from all four approaches. Although Tungsten Street has a moderate downward grade proceeding to the north, it was observed that the limiting factors for sight distances are the homes on all four comers of the intersection. This leads to the conclusion that the sight distances are no poorer at this intersection than any randomly chosen intersection in the sewer and water district which have similar structure setbacks. Accident History.: A review of the accident history for the five year period, including 1993 through 1997, shows one accident at this intersection which occurred in 1995, involving a single vehicle which left the roadway. This accident was not the result of failure to yield the right-of-way. Traffic Counts: One function of a stop sign is to assign right-of-way to main street over lesser-traveled streets. The petitioner's letter points out that the primary road is not clear. Traffic counts were taken by visual observation on Monday, November 16, 1998, from 3:45 p.m. to 4:45 p.m. and Monday, November 23, from 4:45 p.m. until 6:00 p.m. This has been shown by other studies to be peak afternoon traffic periods for this neighborhood. There was a total of 38 vehicles (and one bicycle) through this intersection over a two hour, 15 minute period, or an average of one vehicle every three minutes and 33 seconds. Traffic volumes of this magnitude have a low probability of having two or more vehicles entering the intersection simultaneously. However, when such events do occur, it is a better practice to have each motorist assume responsibility for proceeding safely through the intersection, rather than to rely on a stop sign which one of the approaching motorists may be in the habit of observing with some degree of laxity. Speed Assessment: The petitioner's letter references high speed through the intersection. A speed study has been scheduled for the week of December 7, 1998, but is not available