Effects of Road Improvement on Safety: A Case Study of Nairobi-Thika Superhighway

Road safety is one of the main transportation problems in developing countries. The major goal of the transportation system is to enhance mobility and road traffic accidents are unwanted by-products which have to be minimized while achieving the primary goal. Road safety engineers are faced with the challenge of addressing safety issues within the three major traffic safety pillars: human, vehicle, and infrastructure.All three aspects must be part of a traffic safety plan and dealt with subject to budget limitations. The project involved redesigns of all intersections and increment in the road lanes to enhance capacity and improve safety. The research study aimed to review the occurrences of crashes on the improved Thika-Nairobi superhighway in three phases; before, during and after construction. This research sought to assess the role of incorporation of different safety measures in road projects in Kenya and is anticipated to improve public awareness on the use of road safety provisions with the aim of reducing road traffic accidents and subsequent casualties. The approach used to realize this study involved gathering data from traffic police stations, conducting interviews to get the opinions of road users on safety and making observations on the turning movements of vehicles and pedestrians. The interactions were explored, analysed and modelled using Chi-squared distribution. These were then used to identify accident black spots and assess the effectiveness of road safety measures installed in the new super highway. This study revealed that the large number of accidents occurred in the years before and at the start of construction, reduced during construction and increased again after completion. The primary type of accidents along the highway is vehicle to pedestrian and vehicle to vehicle. Githurai 45, Safari park and G.S.U were established to be black spots. The most efficient road facility was found to be foot paths, and foot bridges.