For the millions of Americans who live near the nation’s highways and freeways, traffic noise is a huge problem. In addition to being an annoyance, traffic noise can also lead to hearing loss and other health problems.
In 2003, Arizona launched a three-year, $34 million Quiet Pavement project to re-surface 115 miles of Phoenix area freeways with rubberized asphalt, a type of resurfacing treatment that reduces traffic noise. According to the Arizona Department of Transportation, rubberized asphalt has been used in several states for more than 20 years. However, in the past few years, there has been a push to expand the use of rubberized asphalt because it can provide a smoother ride for motorists and quieter neighborhoods for those who live near a freeway or highway.
Currently, tests are underway in other parts of the United States such as Washington and Colorado to see if rubberized asphalt is a durable, cost-effective solution to reducing traffic noise. According to the Washington State Department of Transportation rubberized asphalt costs at least 50 percent more per lane-mile than standard asphalt, however because less materials are needed to pave roads, rubberized asphalt may be cheaper. While Arizona’s Quiet Pavement project was successful, the testing program in Washington proved to be fairly unsuccessful in reducing noise which many attribute to the differences in climate.
If you are interested in learning more about quiet pavement, here are five FAQs about rubberized asphalt (also known as quiet pavement).
1. What is Rubberized Asphalt?
Rubberized asphalt is made from mixing regular asphalt with around 20 percent ground used tires known as “crumb rubber.” Because around 1,500 tires are used for every lane-mile of rubberized paving, the amount of landfill space dedicated to used-tire processing could potentially be reduced. Rubberized Asphalt is also known as quiet pavement because it can reduce traffic noise by an average of 4 decibels, or 50 percent of freeway noise.
2. What advantages does Rubberized Asphalt have?
According to the Arizona Department of Transportation, in addition to reducing traffic noise, rubberized asphalt has also been used as a “pavement preservation” strategy because it:
- Does not reflect cracks from the existing pavement
- Is more durable and skid-resistant
- Contributes a less bumpy car ride
3. Is the effectiveness of Rubber Asphalt affected by weather?
Rubberized asphalt can only be applied when the surface pavement is between 85 and 145 degrees for the material to adhere properly. Although there is no concrete evidence linking weather to the effectiveness of quiet pavement, Washington has attributed their mixed results from their test program to their northwestern climate.
4. What is the lifespan of rubberized asphalt?
Rubberized asphalt overlay has a shorter lifespan than a concrete overlay, however it has a longer expected lifespan than conventional asphalt. Some experts have voiced concerns about environmental concerns when the rubberized asphalt begins to deteriorate.
5. What are alternatives to rubberized asphalt?
Until recently, concrete barriers (or noise walls) have been the only federally acceptable means of reducing traffic noise. Currently barrier wall construction costs $1.3 and $3 million per mile. However, when there is a gap between barriers, buildings within the gaps do not benefit from noise reduction. Furthermore, when noise walls are built parallel to one another echoes generated may actually increase noise levels.
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