Expansion of residential areas of Bangkok occurred along the main roads radiating from the city center. The main road corridor follows a northeast to southwest axis. This corridor was divided three zones. As shown in Fig. 3, the three circles represent the different urban development density zones of Bangkok. The center of the circles was set at the heart of the city where the selected road corridor begins. The smallest circle represents the inner zone with high urban density. The middle circle encompasses the intermediate zone where there is medium urban density. The largest circle depicts the outer zone having a lower urban density as categorized by BMA. In each of these zones, the district with the highest elder population was selected. In each district, sub-districts with predominately residential areas were selected for inclusion in the study. These sub-districts were (1) Jakrawat (JWK), (2) Bang Sue (BSE), and (3) Thungsonghong (TSH) (Fig. 3).