Height of new Silverdale roundabout middle is no accidentJanuary 25th, 2013 by travis baker
The in basket: Retired educator Dick Barich is the second person to contact me with the opinion that the “Welcome to Silverdale” monument in the middle of the new Silverdale roundabout at the base of Newberry Hill Road is too high.
It obscures the view of oncoming traffic already in the roundabout, he said, and unnecessarily reduces the reaction time for a driver approaching on Newberry Hill to decide whether to pull into the roundabout, he said.
The out basket: I had a feeling the county had considered this in the design of the roundabout, and it didn’t take long before Tina Nelson, Kitsap County engineering’s senior project manager, provided me with the rationale.
“A raised center island is a preferable feature in a roundabout,” Tina said. “This is so that drivers entering a roundabout are not focused on, or distracted by, cars opposite the roundabout which should not be a concern.
“The goal is to have the driver’s focus on pedestrians and the vehicles within the roundabout that they would have a conflict with. It is actually recommended that the sight distance for entering the roundabout be kept at the minimum required, again with a focus on getting drivers to slow down.
“The wall also provides a visual cue to drivers that they are approaching a non-standard intersection, as well as a break in headlight glare of oncoming vehicles,” Tina said.
She provided an online link to the state Department of Transportation’s design manual for roundabouts,
http://www.wsdot.wa.gov/publications/manuals/fulltext/M22-01/1320.pdf, pages 1320-40, which will tell you a lot more about them than you ever wondered about. Or, she said, Google “roundabouts” and you’ll get even more.