WHY WE ARE CONCERNED ABOUT ROUNDABOUTS ON SR162 

 

ROUNDABOUTS WORK...

  • When traffic flow is at normal levels (not gridlocked levels)

  • With minimal truck traffic

  • With the majority of traffic flowing in a straight through direction

  • When there are few pedestrian, jogger and bicycle crossings

  • When there are few uncontolled access points to the highway and traffic allows spacing to safely enter the highway

  • These conditions ARE NOT FOUND on this corridor

TRAFFIC CONDITIONS 

  • This transportation corridor is currently in gridlock conditions during peak commuting hours

  • SR162 currently level “F” (fail) WDSOT highway peak hour rating

  • Tehaleh highway to add 1000 more cars per peak hour

COMMERCIAL TRUCK TRAFFIC ON SR162

  • Currently over 1500 trucks* of all types each day will be negotiating this roundabout with cars (most are tractor trailer combinations and this number will increase when the new road opens)

  • Truck combinations and vehicles do not mix well in roundabouts

HIGHWAY ACCESS AND EGRESS

  • Roundabouts meter exiting traffic evenly creating little spacing in traffic downstream

    • Breaks in traffic along corridor are necessary for access and egress to SR162

    • There are 140 access/egress points along SR162 between Sumner and Orting

    • Business patrons, farmers, and residents will experience dangerous conditions entering and leaving the highway

  • Traffic signals provide significant breaks in traffic to allow safe entry and exit

SR162 / 128th St E INTERSECTION

  • A majority of southbound evening traffic will be turning left onto the Tehaleh highway, stalling all northbound SR162 traffic from Orting

    • Lets do the math:  2000 going to Tehaleh-hr / 60 min = 33 vehicles per minute (that is 1 vehicle every 2 seconds making a left turn)

  • Vehicles within a roundabout have the right-of-way restricting entry

  • The size of roundabout intersection will be much larger than a signaled intersection requiring elimination of more properties and the McMillin rural neighborhood center zoning

FOOTHILLS TRAIL

  • The Foothills Trail parallels SR162 and connects with intersections at Military Road and at 128th St. E.

  • Mixing trail users with congested roundabout traffic creates a clear danger

  • Traffic signals provide designated passage periods for trail users and pedestrians

PEDESTRIAN CROSSINGS

  • Pedestrian crossings take place just outside of roundabout intersections

  • Pedestrian crossings cause interuptions to roundabout flow

  • Safety is a large concern when drivers attention is on heavy roundabout traffic

  • Roundabout crossings use safety islands between traffic lanes dividing the crossing process into two phases

  • Traffic signals provide a dedicated time for pedestrians crossing

VALLEY EVACUATION

  • SR162 is the only valley transportation corridor for valley evacuation

  • Coming center turn lane will add a third one-way lane during evacuation

  • However, a single lane roundabout will only accommodate two of those lanes of traffic causing an evacuation choke point

  • Disasterous situation!

 

* 2017 SR162 Sumner to Orting Congestion Study

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