Impacts of pavement performance indicators on traffic oriented parameters and road safety

With the passage of time, due to vehicle movement and environmental conditions, the road pavement deteriorates. The accident rate increases if there is no proper maintenance of road deterioration. This study evaluates the safety performance due to the change in pavement performance indicators on the selected roads of Bahawalpur, Punjab Pakistan. Three roads different pavement conditions were selected, based upon their physical inspection, of 5 Km length (each road). The pavement performance indicators used in this study were International Roughness Index (IRI), rutting and cracking. The accident data of last five years (Jan 2015 to April 2019) was used in this study. The pavement performance indicators were measured on site and accident data was taken from emergency service (Rescue 1122). The relationships between pavement performance indicators and accident data were examined. No linear relationship is found between pavement performance indicators and traffic safety, however a parabolic relation is best fitted between these variables. The parabolic models are developed by keeping the pavement performance indicators on independent axis and accident data on dependent axis which can be use by road designers for assessing the value of IRI, rutting and cracking for safe traffic flow. Some values are also suggested which can be used as evaluation criteria that whether the road needs rehabilitation work or not. The suggested values/range for IRI is 1.75-2 m/Km, for rutting 9 – 10 mm and for cracking-Pavement Condition Rating (PCR) 75-80.