In response to Jeff Switzer's article : "Neighbors pushing for quiet pavement for the new 520 bridge", dated 1/12/05 :
This article quotes Mia Waters from WSDOT ; On September 13, 2004,Ms Waters attended the Sound Transit EIS appeal hearing for the proposed I-90 HOV project vrs the SW Bellevue residents who were in favor of the project but claimed that Sound Transit had ignored the merits of "quiet pavement" aka "Rubberized Asphalt " ("RA"); In this hearing , Ms Waters learned from AZ DOT material expert engineer, George Way, all supported by actual data, the following :
A) More effective: 70% of road noise is generated from road/tire contact , so to cut the noise at the generation spot has been determined to be most effective (vrs very expensive and view blocking noise walls).
B) More cost-effective: While RA is more expensive per volume ( expensive adhesives aka"binder" and the ground up used rubber tires) , it can be layed thinner( 1" thick ) than traditional asphalt overlays (3-5 inched thick), so the comparable cost of overlay is cheaper and faster because the increased binder content permits a thinner application .
C) Longer maintenance cycle( more durable): Due to the toughness of the rubber, this product holds up to heavy machinery ( ie chains , snow plows ,tire studs ) , than the WSDOT's standard practice asphalt overlay. As a result, the AZ DOT engineers requested RA for the Interstate through Flagstaff, Az due to its adherence to the surface in cold weather and durability to the chains, studs and snowplows. RA is still in place on the Interstate though the mountain pass near Flagstaff and the AZ DOT reports that it holds up better than the original concrete surface which is brittle , especially in freezing temperatures. In fact, RA was originally designed as a more durable maintenance product. It's sound absorbing qualities were not noted until later. RA is used now in many countries ( ie Germany, Korea, Japan, Australia, Spain ) . In North America, RA is used in Alberta and BC, Canada , In the US , Minnesota, California, Arizona, Texas and several Eastern seaboard states use RA.
D) Safer : Due to the more porous nature of RA , it is 13% more skid resistant and doesn't "pond" therefore avoiding the truck spray - (ever try to pass a truck at night in the rain ?)
E) Environmentally Sensitive: Each lane mile uses approximately 1,000 used tires that otherwise are dumped in landfills. Since Arizona started their program of overlaying even NEW asphalt in urban areas, they now recycle 70% of the State's total used tires back into their highways.
F) Noise Reduction : Data availiable shows that the decibel ("dBA") decrease can be up to 13 dBA decrease ( measured at the edge of Interstate) and that the average range of noise reduction is 4-7 dBA . Because the dBA scale is logrithmic , this average decrease is approximately 35%-40% decrease !
Subsequent to this appeal hearing ,on September 13, 2004 @ 7:30 PM , Mia Waters attended a Town Council of Beaux Arts ; where she and WS DOT Engineer, Baker, learned that the "open - graded " asphalt to which they were referring that "only adheres in warm weather" was NOT Rubberized Asphalt("RA") and therefore not even relevant ! In fact, the State of Washington has no direct experience w/ the current form of RA . Yet , Ms. Water ,continues to state that RA will not hold up to studded tires and will not adhere to the concrete or will lose it's noise reduction- effectiveness over time. The data does support a very minor degradation of noise reduction capabilities over time - in the reduction range of one dBA . Notwithstanding Ms Waters' statements to the contrary , this actual data proves otherwise. Ms Waters states that WSDOT will do a "white paper" on the subject and they will do an EIS this Summer for SR 520 , but how can WSDOT really evaluate RA if they have no actual data of their own ? Why would they resist this when it can only reduce their budget and mitigate citizen opposition to their projects by minimizing noise and unsightly, expensive , relatively ineffective noise walls ?
The communities of SW Bellevue, Medina, Hunts Point, Yarrow Point, Clyde Hill, Beaux Arts, Montlake and Beacon Hill/Leschi are in support of real, in place ,actual tests of Rubberized Asphalt in this area by WSDOT of Rubberized asphalt. For updates on this issue and to learn about upcoming citizen's meetings planned with elected officials, internet users can connect with the website for Eastside Citizens For Responsible Development @ www.ecrd.net <file://www.ecrd.net>
As anyone driving I-5 or I-405 knows, these highways are severely rutted and are overdue for resurfacing. The big question to those affected residents is: Will the overlay be sound absorbing "quiet" pavement ? Is WSDOT here to serve the citizens ? Given the actual data proving these qualities of Rubberized Asphalt , is this request of WSDOT by the residents excessive ? Come on WSDOT !