On the road, silence has a price

In July one weekend they closed down the 520 floating bridge.  They seem to do this once or twice a summer to do walk-overs and do general repairs.  To my surprise after that weekend they had done some paving on the east side of the bridge running through Medina, Clyde Hill, Hunts Point, Yarrow Point, ending just west of where Bellevue Way intersects SR 520.  This was not normal paving but it was the testing of quieter pavement.  On 520 there are two sections with one containing polymer-modified quieter asphalt and another section containing rubberized quieter asphalt.  Personally I cannot tell the difference between the two while driving.  It really is night vs. day when you enter and exit this paved section.  The reduction in noise is quite amazing.  The WSDOT has lots of information about where they are testing.  The interesting is the price difference between the types of pavement.  The site only gives values for the work they did the previous summer in Lynwood so one would think that the price may be more now.

Cost to lay down quieter pavement on southbound I-5 in Lynnwood (summer 2006)

• Standard (hot mix) asphalt – $58,900 per lane mile
• Polymer-modified quieter asphalt – $81,600 per lane mile
• Rubberized quieter asphalt – $93,200 per lane mile
• Quieter concrete (texturizing existing concrete) – $100,000 per lane mile
• Quieter concrete (texturizing and installing new concrete) – $2 million per lane mile

It will be interesting to see how it holds up over time.  A few days after you could drive on it there was a slight rain.  My first thought was "I need to test this" and making sure I was not being tailgated I pumped my brakes to see how the stopping power was.  I found no difference between stopping on it versus other pavement.  No sliding or anything like that.

I should note that when they paved 520 they also replaced the center barrier which had years of bumper stickers applied to it.  Many were local beers and other meant things that only Microsoft employees could apprechiate like "MDAC" in the standard European country sticker in the shape of a white oval with black text.  It did not take long however to have new stickers appear on the new barrier.  So far I have not seen very many fun ones but it is still early in the age of the new barriers.

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