Investigating Effects of Road Geometry on Accident Blackspot of Addis Ababa to Gohatsion Trunk Road
No Thumbnail Available
Date
2023-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Ethiopia is experiencing high number of traffic accident record contrary to the low road network
density and least number of vehicle fleet when compared to the world. The increase in
occurrence of traffic accident is due to increase in motorization without regulation and rapid
population growth and increase in road network density with poor attitude and safety
consideration while designing and constructing the roads. Along with expansion of the road
network mandatory road safety policy was not developed, clear and updated legislations were not
formed and capable institutional organization for implementation were not established to take
safety into consideration at early stage of the design of the road. The purpose of this study is to
identify the black spots along the road under the study and to investigate the relationship of the
geometric design parameters of the road at blackspot locations with road traffic accident when
compared to the recommended standard set by ERA. Three years‟ traffic crash data were
collected from six woredas (Wacaalee, Debrelibanos, Giraar Jaarsoo, Dagam, Kuyyuu and Warra
Jaarsoo) and three town administrations (Fitche, Chancho and Sululta) along Addis Ababa to
Gohatsion trunk road and as built data were collected from Ethiopian Roads Administration
(Road Asset Management Directorate). Supporting these secondary data with primary data,
thirty-seven blackspot locations were identified using Rate Quality Control (Accident Rate,
Accident Frequency and Severity Index) method and Accident density method and these 37
blackspot locations are mapped using GIS Software. The geometric design parameters of the
road at these black spot locations are further analyzed using SPSS software. Multiple linear
regressions were fitted to explain the number of accident based on lane width, shoulder width,
supper elevation, vertical curve, gradient, 85th percentile speed and minimum clear zone. Among
the explanatory variables supper elevation significantly affects number of traffic accident,
whereas others moderately.
Description
Keywords
Geometric Parameters, Traffic Accident, Blackspot, Multiple Regressions