Every Rose Has Its Thorn: Reader's Response Draft 2

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 or parking lots exclude small aggregates to allow water to pass through, acting like a filtration system. Thus, this reduces flooding and erosion. Superhighways also use porous asphalt because it helps to drain water, improve water quality, removes 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.

I strongly agree that Porous Asphalt roads are good at tackling flooding and safety. However, the article has not targeted 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. However, I feel that it is feasible in countries such as 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 United States have wider roads and larger parking lots which could hold a large amount of rain water in its Porous Asphalt bed over time compared to India, where roads are narrow, and carparks are small.

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 on the Superhighways. This could be further proved by Ferguson (2005) who wrote in his book "Porous Pavements" that it could give 'better traction and visibility' on highways. But it is stated in the article "Accident Analysis & Prevention" by Elvik (2016) that there is an insufficient change of accident occurrence between porous asphalt and conventional in accident rates, evaluated by nine different risk factors.

Despite agreeing that Porous Asphalt helps in flooding and safety, I do not agree that it would save cost as stated by the author. The author did explain how the overall construction cost will offset the extra cost incurred on the stone bed which is thicker than conventional asphalt. However, the author did not explain on the durability on Porous Asphalt itself compared to conventional asphalt. Loosdrecht (2012) noted 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. With the above in mind, I do not agree that the cost of having Porous Asphalt which is the same as conventional asphalt.

In conclusion, Porous Asphalt is a good way to decrease flooding and increase safety. Weighing the pros and cons of using porous asphalt, the benefit of increased safety on the road outweighs the cost of maintenance. Singapore should try to incorporate this method into our urban landscape such as increasing the floor bed to maximize holding volume. This could help reduce the flooding incidents that have been happening frequently in Singapore.

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