A Review of Pedestrian Flow Characteristics and Level of Service over Different Pedestrian Facilities

Present paper reviewed the past studies on pedestrian flow characteristics (such as speed, flow, density, space, free-flow speed and jam density) and development of Pedestrian Level of Service (PLOS) for various pedestrian facilities (i.e., sidewalk, walkway, crosswalk, grade separated, stairways and escalators). Fundamental relationships (between speed and density) were observed over different facilities and were found to be significantly different. The fundamental relationships for sidewalk facility predicted the range of free flow speeds to be 65 − 85 m / min and jam densities to be 3 . 5 − 5 . 3 ped / m 2 . The minimum and maximum pedestrian speeds over sidewalk facility in different countries observed were 52 m / min and 98 m / min respectively, with a mean speed of 79 m / min . The male pedestrians walked at 4 − 9 m / min higher speed in comparison to their female counterparts; while the older pedestrians walked at 15 − 20 m / min lower speed than the younger ones over the various types of crosswalk facilities. Similarly, speed-density relationships for ascending and descending stairways showed that the difference between the two directions varied between 4 − 12 m / min , and that the speed was significantly higher in case of descending direction. Moreover, the jam densities for stairways were also observed to be lower in case of descending direction, as the pedestrians generally maintain higher gap (than in ascending direction) with other pedestrians in front to avoid pushing and the risk of falling down. The flow characteristics were significantly influenced by the type of facility, width, age, gender and location of the study. Primarily factors such as physique (height), culture (dress), attractions (presence of hawkers located along sidewalks), friction (due to parked vehicles), purpose of walking trip and environmentl conditions were the main reasons for pedestrians of countries such as Saudi Arabia, Iraq, Bangladesh, Indonesia and Sri-Lanka to walk significantly slower than the counterparts pedestrians in the USA, UK or Canada. The review conducted on the PLOS mainly looked into the type of survey conducted (qualitative vs. quantitative), LOS parameters and the various software/models used in development of LOS. Researchers from the USA and Japan preferably used both qualitative and quantitative approaches in defining LOS over sidewalks; while in India, China and Malaysia qualitative method was highly preferred. Pedestrian volume, safety, surface, obstruction and width were observed as essential parameters for qualitative survey while density, flow rate, pedestrian speed and width were used in quantitative survey for sidewalks. In developing the PLOS over sidewalk facility; Conjoint analysis, Landis method, HCM method, affinity propagation cluster algorithm and Gainesville method were preferred by various researchers. Studies conducted over crosswalk facility measured space, flow rate, vehicle volume and delay as the most significant factors in developing LOS based on quantitative technique; while vehicle speed, pedestrian volume and traffic control were mostly used for LOS development using qualitative technique.