Cloudiness has an important influence on the incident solar radiation, reducing the amount of solar radiation incident to the pavement or other ground surfaces. To examine the influence of clouds on the albedo of pavements, the albedo of asphalt pavement (B2) on days with different cloud levels were measured for comparison. As shown in Fig. 11, the cloud levels over the days 3/9/2012-3/19/2012 are different. The cloud levels on 3/13/2012-3/17/2012 are much higher than all the other days during this period, during which the incident solar radiations are quite low. The mid-day albedos (∼0.05) during the cloudy days and resultant low incident solar radiation is much lower than those (0.08) on days with few clouds or clear days. This implies that the albedo should be measured on a clear day. Otherwise, a lower albedo will be given, even measured at mid-day.