2.2.6.3 Reduction of headlight reflection and glareSince porous asphalt acts as a drainage layer, rainwater can seep through the mixture, reflection and glare from vehicle headlights are reduced and therefore visibility Painted pavement markings on the wet surface at night can be improved (Manfred N. Partl, 2006) . Despite this, driver visibility at night can be improved by reducing glare. 2.2.6.4 Noise Reduction A high air void content and maximum stone size of the porous asphalt surface are essential for the degree of sound absorption, while smaller aggregates tend to produce less noise (Student, 2005). In addition, the noise produced between the surface and the vehicle tire can be absorbed by the macro-coarse structure of the porous asphalt surface (Manfred N. Partl, 2006).2.2.7 Disadvantages of porous asphaltUnfortunately, although that porous asphalt has many advantages, but there are also some disadvantages for road safety and the environment.2.2.7.1 Aging and strippingAccording to Ali et al. (2012), porous asphalt pavements age much faster than normal asphalt due to their high porosity. Additionally, rainwater can diffuse into the porous matrix and make the asphalt wet since the water remains in the pavement structure. Thus, the binder film could be displaced from the aggregate surface due to moisture damage. 2.2.7.2 Clogging Loss of permeability due to clogging is another factor that affects the performance of porous asphalt pavements. The benefits of noise reduction and drainage function will gradually disappear if the pores affected by clogging are lost (Manfred N. Partl, 2006). The pores in porous asphalt can become clogged with dirt, dust or other contaminants. The middle of the paper should be sifted with crushed hard rock, angular in shape and free from dust, clay and other harmful substances. substances (PWD Malaysia, 2008). With reference to the PWD Malaysia Standard Specification for Road Works (2008), coarse aggregates should not have an abrasion and impact loss in a Los Angeles machine of more than 25% when tested in accordance with ASTM standard C 131. Since porous asphalt is primarily used as a wearing course, it is essential that the aggregates resist polishing. The value of polished stone when tested in accordance with MS 30 shall not be less than 40 (PWD Malaysia, 2008). As noted above, the fine aggregates suggested to be used should be sieved quarry fines only. According to the standard specifications of PWD Malaysia (2008), fine aggregates must be non-plastic and free from clay, silt, material aggregates, vegetative substances and other harmful substances..