Arash Sadrayi - M.Sc. Student, Department of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran
Mahmoud Saffarzadeh - Professor, Department of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran
Amin Mirza Boroujerdian - Assistant Professor, Department of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran

Pedestrians are among the most vulnerable road users. Speed of vehicles is considered as one of the major causes ofdanger for pedestrians crossing the street. Therefore, it is of utmost importance to devise suitable solutions to reducespeed of vehicles. One of these solutions is installation of Pedestrian Refuge Islands (PRI) in very wide midblocks.With regard to fluctuations in pedestrian and vehicle traffic volume in traffic hours, there are different variations incollisions between vehicle and pedestrian. In this article the effect of constructed PRI in Tehran on speed of vehiclesand consequently their effects on probability fluctuations of fatal accidents are determined. Speed of vehicles in twophases of before and after arriving to the PRI is assessed. Additionally, speed of vehicles in non-observed volumes ofvehicle and pedestrian are calculated using Aimsun.v6 simulation software. Paired T-test is applied to compare averagespeed of vehicles before and after the PRI. The results revealed that except for traffic volumes of 3000-4000 veh/hand 400-600 ped/h in other volumes reduction of average speed of vehicles as a result of PRI is significant. Also, theresults show that in all volumes, these equipment reduce the probability of fatal accidents to under 10%. Accordingto the results, it is recommended that PRI should be installed in mid blocks where traffic volume of vehicles in eachlane is less than 750 veh/h.

Pedestrian refuge island (PRI), before and after studies, fluctuations of speed of vehicles, probability ofpedestrian fatal accidents