In the article, "Porous Asphalt Is King of the Road" on the website Pave Green (n.d), it was stated that porous asphalt is beneficial in terms of the environment, safety and the cost. Porous asphalt earned its recognition from the Environmental Protection Agency and has been used all around the United States. It was indicated that porous asphalt roads and parking lots exclude small aggregates to allow water to pass through, acting like a filtration system. This reduces flooding and erosion. Superhighways also use porous asphalt because it helps to drain water, improve water quality, remove splashes and significantly reduce accident rates. The article also mentioned that porous pavement is beneficial in wintery climates because it allows snow to liquify quicker, which saves the cost of anti-icing agents, making it cost-effective and eco-friendly. Although the cost of porous asphalt is higher, the overall cost of construction balances out from the savings made from water pipes and inlets. Despite agreeing that Porous Asphalt roads provide beneficial properties, I find that the author did not target on the disadvantages and challenges it faces. The article could provide more balanced viewpoints on porous asphalt and evaluate them.
The above article has mentioned the advantages of porous asphalt at tackling flooding. Porous asphalt allows water to drain reducing flooding. However, I feel that it is only feasible in countries such as the United States or Australia. These countries have huge land space and even spread population compared to India where land is abundant but in separated villages or Singapore itself, where land source is limited. In the article "Paving Paradise: The Peril of Impervious Surfaces", Frazer (2005) states that countries like the United States have wider roads and larger parking lots which could hold a large amount of rainwater in its Porous Asphalt bed over time. Compared to India, where roads are narrow and carparks are small. This suggests that porous asphalt is only efficient in areas when applied over a large area. This further supports that porous asphalt may not be applicable in countries with limited land space.
In addition, the article state that safety plays an important role in making Porous Asphalt "King", as it helps to reduce the amount of water on the surface of Superhighways. Stating that this provides better visibility on roads reducing accident rates. However, in the article "Accident Analysis & Prevention" by Elvik (2016) state that there is an insufficient change of accident occurrence between porous asphalt and conventional in accident rates, evaluated by nine different risk factors. While porous roads provide increased safety properties, the article has proved that there is no visible change in the usage of porous and conventional asphalt.
The author mentions porous asphalt being cost efficient through reduced usage of anti-icing agents and construction of drainage. The overall construction cost will offset the extra cost incurred on the stone bed which is thicker than conventional asphalt. Loosdrecht (2012) stated in the book Water Research that over time, the filtration bed underneath will get clogged causing a layer or "cake" which prevents water to pass. Maintenance by "vacuuming and sonication" could be used to unclog the beds but not totally, hence would still be a problem in the long run. It is evident that even with regular maintenance to prevent clogging of the roads, porous asphalt will fail in the long run. This led us to wonder if the cost of maintenance of the porous asphalt would be less than using conventional asphalt.
In conclusion, the article has effectively mentioned the successful application of porous asphalt in the United States. The porous asphalt is environmentally friendly, cost-efficient and increases safety on roads. However, I believe that there is no perfect solution to any issues and we cannot only look the advantages and fail to evaluate the possible disadvantages.
Reference:
Porous Asphalt Is King of the Road. (n.d.).
Retrieved February 18, 2018, from http://www.pavegreen.org/index.php?option=com_content&view=article&id=58%3Aking-of-the-road&catid=35%3Aporous-asphalt&Itemid=110
Elvik, R. (2005). Road safety effects of porous asphalt: a systematic review of evaluation studies. Accident Analysis & Prevention.
Retrieved February 18, 2018, from https://www.sciencedirect.com/science/article/abs/pii/S0001457505000175.
Lance Frazer (2005). Paving Paradise: The Peril of Impervious Surfaces
Retrieved February 01, 2018, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1257665/
Loosdrecht M. V. (2012). Water Research
Retrieved February 01, 2018, from https://www.sciencedirect.com/science/article/pii/S0043135411006166
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