Traffic Congestion and Performance of Road Safety along Outer Ring Road in Nairobi City County, Kenya

Traffic safety remains a critical concern for Kenyan transport authorities, particularly in urban areas where rapid population growth and vehicle use have strained existing infrastructure. Grounded in the traffic theory, the study examined the influence of traffic congestion on performance of road safety along Outer Ring Road, Nairobi. The study used a convergent parallel research design to collect both quantitative and qualitative data simultaneously, analyzed independently and triangulated. The target population comprised 2,190 Matatu drivers on Outer Ring Road, four NTSA officials, and ten KURA representatives. A sample of 338 drivers was selected through probabilistic sampling, while 14 key informants were purposively chosen, totaling 352 participants. Data were collected using structured questionnaires and interview guides. A pilot study was conducted on Jogoo Road to enhance validity and reliability of tools. Data analysis included descriptive and inferential statistics, with qualitative data analyzed thematically and reported verbatim. A 90% (n=303) response rate was achieved. The data collection instruments showed high internal consistency, with Cronbach’s Alpha reliability coefficient recorded at 0.772 on traffic congestion and 0.763 for Performance of road safety constructs. Results showed that traffic congestion significantly affects road safety, fuel efficiency, and travel reliability along Outer Ring Road (mean = 3.83; SD = 0.443). Key informants confirmed these findings, citing increased travel costs and delays. Pearson correlation indicated a strong, positive, and significant link between congestion and Performance of road safety (r = 0.987; p = 0.000), while regression analysis showed congestion as the most influential factor, explaining 90.7% of the variation in safety outcomes (Beta = 0.907; p = 0.000). The study concluded that traffic congestion is a major determinant of performance of road safety along Outer Ring Road in Nairobi, statistically significantly influencing performance of road safety along Outer Ring Road.