Open-graded friction courses (OGFC) are a porous asphalt surface course used on highways to improve driving safety by removing water from the surface. These use an open-graded mix design for the top layer of asphalt. Unlike a full-depth porous asphalt pavement, OGFCs do not drain water to the base of a pavement. Instead, they allow water to infiltrate the top 3/4 to 1.5 inch of the pavement and then drain out to the side of the roadway. This can improve the friction characteristics of the road and reduce road spray. [26] Single-sized aggregate [ edit ] Mechanized installation, specialized paver installation equipment speeds construction time by installing approximately one square yard (one square meter) of pavers at a time in rapid succession. Treated water runoff is stored in the reservoir bed, a highly permeable layer of open-graded clean-washed aggregate with at least 40% void space. A wide variety of edge restraints are available and range from timber to plastic to concrete to steel or aluminum as well as cut stone The most significant benefit of porous asphalt use is that it reduces the number of pollutants carried to a storm drain or waterway. Land development has always had the detrimental effect of vastly increasing the amount of impervious surface area as the land is bulldozed and paved to create roads and parking lots.

For roadways, other significant benefits include reduced noise from tires and engines, increased wet-weather friction, improved wet-weather visibility, less tire spray, and reduced risk of hydroplaning. Cost benefits of using Porous Asphalt The system worked well initially, but no one knew how it would perform in severe weather conditions. When a severe storm flooded roads and rivers all over the Salem area in January of 2012, Pringle Creek community experienced nothing more than a puddle or two. a b c Tota‐Maharaj, Kiran (2010-09-01). "Efficiency of permeable pavement systems for the removal of urban runoff pollutants under varying environmental conditions". Environmental Progress & Sustainable Energy. 29 (3): 358–369. doi: 10.1002/ep.10418. S2CID 98361597 . Retrieved 2020-12-16.The result is a strong material that can be trowelled onto a prepared concrete base (also permeable). This surface is non-slip, not prone to ice or frost, and is easy to care for. It also lasts for around 20 years, making it one of the longest lasting driveway materials. Uni-Group USA offers a software design program which uses the US EPA Stormwater Management Model (SWMM 4.30) for the design of permeable pavement. Permeable pavers play a crucial role in preventing soil erosion. In conventional paving, the surface runoff generated during heavy rainfall can lead to erosion of the surrounding landscape. In contrast, permeable pavers allow rainwater to infiltrate directly into the ground, which reduces the volume and velocity of runoff, and thereby minimizes the risk of erosion. Environmental Impact of Permeable Paving Permeable paving can be created using various materials, each providing a unique aesthetic and benefit:

There are several different approaches that can be used to create a permeable driveway and each uses a different set of construction techniques and materials. Here follows a run down on each of these and their relative pros and cons: Reinforced Grass Driveway and Parking Grass can also be used as part of a permeable paving solution. A grid system is typically used to protect the grass roots and maintain the structure of the surface, while still permitting water to percolate through.

Performance of Permeable Paving

Impervious surfaces such as parking lots and paved roads are often the causes of stormwater runoff, carrying residues into streams and waterways. Although detention basins and reservoirs are effective in slowing the rate of runoff, they require additional land. Many consulting engineers and public works officials have turned to porous asphalt pavements to promote infiltration. What is Porous Asphalt? Commercial parking lots often face issues with water accumulation during heavy rainfall. Permeable paving not only mitigates this problem, but also delivers a sturdy, low-maintenance, and long-lasting surface that can withstand heavy vehicular traffic. Public Parks and Green Spaces