7505 SEAWAY BLVD SEPA 016 - 034 - SEAWAY TRANSIT CENTER Traffic Report 2025-04-14

Draft Memorandum Perteet 2707 Colby Avenue,Suite 900,Everett,WA 98201 I P 425.252.7700 F 425.339.6018 Due to these restrictions, the ideal configuration is to provide two distinct intersections with signal heads for each approach.Striping in between the two intersections will guide drivers around the curve and, if necessary, allow for storage space if drivers do not clear the intersection in time.This zone will be sized based on the left- turn pocket into the transit center,which must be long enough to accommodate one 60-foot articulated bus. Ideally,the pocket would provide some additional room at the front and rear of the bus to act as a buffer, but this is not a requirement.Ideal buffer areas would be 10 feet in front of the bus and 20 feet behind the bus,for a total of a 90-foot turn pocket length. In order to maximize the space available for bus layover at the transit center,the access points for inbound and outbound buses should be located at opposite ends of the transit driveway. The optimal location for this driveway is at the south end of the site because that provides the maximum distance between the driveways ' and the intersection of Seaway Boulevard and 75th Street SW. This places the two-way access point driveway closer to the PUD driveway intersection. The design does not afford any room for a taper in between the existing PUD driveway and the proposed transit center driveway.Therefore,the left-turn lane must develop to the east of the PUD driveway.The preferred setup is to allow transit vehicles that will turn left into the transit center driveway to enter the left-turn lane prior to the PUD driveway,and then continue straight through the intersection to enter the transit left-turn lane. LEFT TURN 0 N LY ONLY EXCEPT TRANSIT signing will be required for the east approach (see detail at right). The turn lane length will be designed based on a detailed turning template model, to be EXCEPT completed with the final design effort. TRANSIT The existing crosswalk on the west leg of the intersection will be removed.A new crosswalk will be installed at the west leg of the intersection with the transit center. Signal Modifications ' The proposed changes will require traffic signal system modifications at 75th Street SW and the PUD driveway. There are three existing signal poles at that location. The pole controlling eastbound traffic is located at the southeast corner of the intersection and will require removal due to the roadway widening in this location.The pole controlling the PUD driveway can remain in place, though pedestrian pushbutton upgrades should be considered because the existing do not meet ADA. The final pole, controlling westbound traffic, is located roughly halfway between the PUD driveway and the proposed transit center entrance.This pole will need to be ' removed because the current mast arm is too short to accommodate a left-turn signal head or signing. A commonly used solution at closely-spaced intersections is a tandem traffic signal.Tandem signals are operated on a single controller to ensure that operations do not break down in between the intersection. Figure 9 shows a possible tandem signal configuration with the existing signals in grey. I I Page 8 File location:X:\Community Transit\Projects\201 10155-Community Transit On-Call\.016-Seaway Transit Center Preliminary Engineering\Traffic\Submittals\02- Revision based on Katherine Casseday Comments\Seaway Transit Center -DRAFT Traffic Memorandum.docx