Why is Avondale so Loud?

Why Avondale is so loud? It is a combination of disrepair, heavy traffic, and the type of surface on the road.

Due to road improvements put on hold for years, this section of Avondale has fallen into serious disrepair. The 2.5-mile drive south from Woodinville-Duvall Road is a joy ride of bumps, dips, patches, cracks and worn-out surface. It’s getting louder by the day as the road is pounded on by heavy car and truck traffic. It has been almost 55 years since Avondale was originally paved. During the last 20 years of area growth, it has evolved from a relatively quiet country road to a virtual highway connecting the Woodinville-Redmond-Duvall corridor with Seattle, Bellevue, and points in all directions. In fact, when the 520 freeway officially ends in Redmond, it becomes Avondale Road so it’s essentially the unimproved end of the highway. The traffic…typically moving at 50+ MPH on this 40 MPH road… is so heavy during peak periods that it can take nearly 5 minutes to pull onto the road and it is almost impossible to cross the road safely unless you are at one of the two lighted crosswalks. Finally, we learned from KCDOT that much of the noise problem can be blamed on the type of material used to construct the road: i.e., concrete. Here is an explanation provided by the KC Roads Division:

“The reason Avondale is loud is because it has a Portland Concrete Cement (PCC) surfacing with expansion joints. Because of the highly rigid and dense mixture of PCC the noise generated between the tire/surface interfaces is reflected more than with an asphalt surface. This is due to the lighter density and flexibility of asphalt which tends to absorb more of this interface noise. In addition to the stiffness of PCC, the road is constructed using concrete panels with expansion joints between each panel. You feel these expansion joints as you tires cross them and they contribute to the noise you hear. PCC costs more to place than asphalt mixes, however it has a considerably longer useful life, lower maintenance costs and can withstand heavier axle loads than asphalt. This is why you will see more PCC on roads experiencing high volumes of truck and bus traffic.” [Jim Eagan, Managing Engineer, KCDOT, 2/14/08]