Asphalt Paving Facts
Vehicles traveling on smooth pavements consume up to 4.5 percent less fuel than when traveling on rough pavements. Asphalt pavements start out smooth and stay smooth.
Less energy consumed in building pavements
Asphalt pavements require about 20 percent less energy to produce and construct than other pavements. Rubblization of concrete pavement with an asphalt overlay also saves energy. The rubblized pavement does not need to be hauled away; new base material does not need to be trucked in; and landfill space is saved. In addition, the need for mining, crushing, and processing of virgin materials is reduced.
Less energy consumed by the traveling public
Reducing congestion—which wastes fuel— by constructing asphalt pavements just makes sense. Asphalt pavements are faster to construct and rehabilitate. Asphalt pavement rehabilitation can be accomplished during off-peak hours. On highly traveled routes, much of this work can be done at night. One or more lanes can be closed after the evening rush hour, milled for recycling, resurfaced, and then opened for traffic the following morning. Most motorists do not have to deal with the inconvenience of construction delay. Because a new or newly rehabilitated asphalt pavement can be opened to traffic as soon as it has been compacted and cooled, there is no question of waiting for days or weeks, with traffic being detoured or squeezed into fewer for the material to cure.
When vehicles consume less fuel, they produce lower emissions. Reducing emissions from vehicles would reduce greenhouse gas production and have a tremendous impact on global climate change.Smoothing out all our rough old pavements with asphalt overlays would be an energy-efficient investment.
In the natural environment, rainfall sinks into soil,f ilters through it, and eventually finds its way to streams, ponds, lakes, and underground aquifers. The built environment, however, seals the surface. Rainwater and snowmelt become runoff which may contribute to flooding. Contaminants are washed from surfaces directly into waterways without undergoing the filtration Mother Nature intended.
When used for parking lots, roads, walking/biking paths, and other applications, porous pavements can turn runoff into infiltration and restore the hydrology of a site or even improve it. Porous pavements conserve water, replenish aquifers, and protect streams.
A typical porous pavement has a surface that looks similar to conventional asphalt, but has tiny pores that allow the water to drain directly through it into an underlying stone recharge bed.
Smooth asphalt roads give vehicle tires superior contact with the road, improving safety. Open-graded asphalt surfaces allow rainwater to drain through the pavement surface, reducing the amount of splash and spray kicked up by vehicles. Resurfacing with open-graded asphalt has been shown to reduce crashes and fatalities on highways.
In Texas, the Department of Transportation placed a "Permeable Friction Course" (the same thing as open-graded asphalt) on a stretch of road where there had been numerous accidents. The chart below shows how crashes, injuries, and fatalities were reduced. What made the difference was probably the improvement in visibility related to the reduction in splash and spray.
Asphalt pavement is a permanent resource that will never be consumed, and because it will never be burned for fuel, it will never emit greenhouse gases. Scientists call this "carbon sequestration." In addition, the asphalt cement - the black, glue-like substance that holds the road together - can be reactivated over and over again through reuse and recycling.
Asphalt is the quiet pavement. Studies show that the noise-reducing properties of asphalt last for many years.Noise reductions of 3 to 10 dB(a) are common. Reducing noise by 3 dB(a) is about the same as doubling the distance from the road to the listener, or reducing traffic volume by 50 percent.
Asphalt pavement researchers have developed a number of technologies for reducing pavement noise. With a quiet asphalt pavement, there's less need for ugly, expensive noise walls.
Asphalt’s speed of construction allows planners and managers a way to fix congestion hot spots and bottlenecks, quickly and cost-effectively. Work can often be done during off-peak hours, so commuters may never see an orange barrel. And when congestion is relieved, idling vehicles don't release excess emissions.