Final Readers Responds

In the article, "Porous Asphalt Is King of the Road" on the website Pave Green (n.d), porous asphalt has proven its benefits by improving the environment, safety and minimizing cost. Porous asphalt has since been recognized by the Environmental Protection Agency and is being used on pavements throughout United States.

Small aggregates are excluded from the porous asphalt mixture to allow water to pass through, acting like a filtration system. This significantly reduces flooding and erosion on roads and parking lots. Superhighways use the same mixture as it helps to drain water, improve water quality, remove splashes and significantly reduce accident rates.

The article also mentioned that porous pavements are beneficial in wintery climates as it allows snow to liquefy at a faster rate, reducing cost of anti-icing agents, making it cost-effective and eco-friendly. Despite the high cost of porous asphalt, the overall cost of construction balances out from the savings made from purchasing water pipes and inlets. While porous asphalt roads provide beneficial properties, there are several disadvantages and potential challenges faced that the author did not discuss on.

Firstly, the article mentioned that porous asphalt is effective in tackling flooding situations as the mixture allows water to drain. However, this may only be feasible in countries with urban infrastructure and evenly spread population such as the United States or Australia.

In the article "Paving Paradise: The Peril of Impervious Surfaces", Frazer (2005) mentions that countries like the United States have wider roads, larger parking lots and houses with accompanying roofs are contributing factors which offers additional protection for impervious surfaces unlike India where the populace live in scattered village without paved roads. This suggests that effects of porous asphalt are efficient in improving the water absorption on impervious surface however there are many contributing factors which assist in reducing floods and erosion.

In addition, the Pave Green article states that safety plays an important role in making porous asphalt "King", is helpful in reducing the amount of water on the surface of superhighway providing better visibility on roads reducing accident rates. However, in the article "Accident Analysis & Prevention" by Elvik (2016)* states that there is an insufficient change of accident occurrence between (on roads with) porous asphalt and conventional in accident rates, evaluated by nine different risk factors. While porous roads provide increased safety properties, the article suggest that there is no visible change in accident rates between the usage of porous and conventional asphalt.

The author mentions porous asphalt was cost efficient through reducing the 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, water clogging would still be a problem in the long run. It is evident that even with regular maintenance to prevent clogging of the roads. 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 it increases safety on roads. However, I believe that there is no perfect solution to any issues and we cannot only look at 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

Frazer, L. (2005, July). Paving paradise: The peril of impervious surfaces. Environmental Health Pespectives, 113(7). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1257665/.

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