Effect of Geometric Design Parameters on Traffic Accident along Black Spot Section; A Case Study Sekoru Town to Gibe River Bridge

Abstract

A traffic accident is one of the series problems frequently occur in developing countries, leads to loss of life and property. In Ethiopia, various road segments are facing to effect of geometric design elements on traffic accidents; one of road section is along Sekoru town to Gibe River Bridge, which is located in Jimma Zone of Oromia Region. The main aim of this research study was to identify the main effects of road geometric design elements that cause road traffic accidents. Therefore, a mitigation of traffic accident is one of the prime concerns. Henceforth, scope of the study was limited to Sekoru town to Gibe River Bridge road segment with a total length of 70 kilometers. This research was conducted using both descriptive and analytical methods; simple random sampling was used for interview, and questionnaires of drivers, the pedestrian’s likewise purposive sampling was used for obtaining of recorded accident data from traffic police office, as a built drawing and annual average daily traffic data from Ethiopian Road Authority. These data were analyzed using prioritization value (P) for the last three years (three or more) road traffic accidents have occurred was first selected, then for value of P≥15 selected as black spot section. Generally, the segment has 15 black spot sections from which 10 black spot sections were found in Sekoru Woreda; Qumbi Muzi tare has the highest 79 P-value and Doma have the smallest 15 p-value and the other 5 black spot section were founded in the Yem special woreda; Kosho has the highest 78 p-value and Saja town has the smallest 18 P-value. Also, analyzing the results based on multiple linear regressions for indicating variables using SPSS and excels tools; the value of R2 is always between 0 and1 because r is between -1 and +1. Normally, when correlating geometric design elements; lane width, shoulder width, radius of curves, vertical curve length, k-value, algebraic difference, stopping sight distance, passing sight distance with road traffic accident; they have R2=0.999 which means strong positively correlate with TRTA and P= 0.035 which is significant because of P<0.05, as a shown in summary of multiple regression output. Therefore, the counter measures are needed because of there is the effects of geometric design parameters brings road traffic accidents as investigated in research.