Influence of Undesignated Pedestrian Crossings on Midblock Capacity of Urban Roads

Pedestrians crossing an urban road at undesignated places are not uncommon in developing countries such as India, and these people force motor vehicles to provide suitable gaps for their crossing. The present study demonstrates the effect of such crossings on the midblock capacity of an urban arterial road. Data were collected on 12 sections of six-lane urban arterial roads in three populous cities in India. Six sections were selected without any side friction to estimate the base value of capacity. The remaining six sections had pedestrian flow across roads at undesignated crossings. Speed and volume data were collected in the field and were used to estimate the capacity of a section. The base midblock capacity of a six-lane divided urban road was found to vary from 1,500 to 2,100 passenger car units per hour per lane in three cities. This variation was attributed to the different free-flow speeds in these cities. The effect of pedestrian cross flow on the midblock capacity of an urban road was evaluated by comparing the capacity of a section with pedestrian cross flow with that of the base section. Finally, a mathematical relation was developed between pedestrian cross flow and reduction in capacity. The results show practically no influence on capacity when pedestrian cross flow is less than 200 pedestrians per hour. The capacity, however, is reduced by 30% when pedestrian cross flow is increased to 1,360 pedestrians per hour.