Effects of Road Improvement on Road User Costs and Safety of Road Users: The Case of Outer Ring Road, Nairobi, Kenya

Abstract

Purpose: This study aimed to investigate whether road improvements promote the safety of road users as well as reduce the costs of road users. The study used the case of Outer Ring Road, Nairobi owing to its large traffic base, high incidence of accidents and having received a major facelift in recent years.

Methodology: The study used a non-experimental research design. Secondary data was collected for 2012 before road improvement began and in 2020 after road improvement. Data processing was done using SPSS software. This means for the study variables before road improvement and after road improvement was generated. The difference in difference (DID) was used for comparing baseline data collected in 2012 and endline data after project implementation as of 2020. This was done with the help of a t-test, ANOVA Test and the Difference in Difference Test. The multivariate linear estimation was to test for significance between the road improvements and the road user costs in 2012 compared to 2020.

Results: With a focus on safety of road users along the road, the median number of fatalities before road improvement on Outer Ring Road (2012) were 3 fatalities which later reduced to 1 fatality in after road improvement 2020. The median number of severe/ serious injuries before road improvement on Outer Ring Road (2012) were 9 injuries which later reduced to 4 injuries in after road improvement 2020. Likewise, owing to the effects of road improvement on Outer Ring Road, the median number of road accidents reduced from 22.12 in 2012 to 15.83 accidents in 2020. Likewise, with regard to road user costs, the median total travel time before road improvement on Outer Ring Road (2012) was 3.77 hours and later reduced to 0.041 hours in after road improvement 2020. The median costs of severe/serious accidents before road improvement on Outer Ring Road (2012) was KES 9.22 billion which later reduced to KES 4.41 billion in after road improvement 2020. Likewise, owing to the effects of road improvement on Outer Ring Road, the median costs of fatalities reduced from KES 2.52 billion in 2012 to KES 1.80 billion in 2020. Therefore, the study based on the above findings concludes that there is a significant interaction between the road improvements along Outer Ring Road, and the safety of road users (mean cost   of fatality) in 2012 compared to 2020. Likewise, there is a significant interaction between the road improvements along Outer Ring Road, and the road user costs (mean total time travelled) in 2012 compared to 2020.

Unique contribution to theory, policy and practice: The study suggests the road agencies to improve the fixing road signs, road markings and enforcements of traffic rules to improve in the road safety performance. The study also recommends the road agencies to enhance expenditure on road repair and conservation in order to improve road safety and reduce excessive fatality rates. This will ensure the awareness of road users on the matters regarding safety of road usage like proper use of traffic lights, switching of lanes, speed limits etc., which could have an effect on the evaluations of road users and road user costs. These study findings will be useful to the future studies for system-based initiatives and may advise government legislation on human or human-environmental interacting aspects to optimize county-level and national-level road safety.