Browsing by Author "Segni, Getu"

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    Causes of Road Traffic Accidents and Possible Counter Measures on Addis Ababa-Shashemene Roads
    (Addis Ababa University, 2007-04) Segni, Getu; Berhanu, Girma(PhD)
    Road traffic accidents occur as a result of several factors associated with the traffic system, namely: road users, road environment and vehicles. In year 2004/5, 93% of all accidents involved human factors, 5% accounted for vehicle factors, and 2% were associated with road environments according to the Federal police report. Despite having low road network density and vehicle ownership, Ethiopia has a relatively high accident records. In this regards, the traffic accident death rate per ten thousand motor vehicles in 2001/02-2004/5 was in the range of 129 and 145. Road accidents are concentrated in few of the regions in the country. The capital city of Addis Ababa and Oromia region account for 58 per cent of all fatal accidents and two thirds of all injuries. This study is carried out to identify black spots and possible causes of road traffic accidents and to identify low cost engineering countermeasures. The research is done by reviewing road traffic growth, the existing legislative framework of road transport, and road traffic accidents for the last four years in the country. Previous studies were also reviewed having access to the information in other countries in order to understand the existing knowledge and experiences. Road and traffic data were collected from fieldwork and accident data were gathered from pertinent police stations. Each accident spots was measured with reference to kilo meter post that is available in the Addis Ababa-Shashemene road. A total of 1108 reported accidents were collected out of which 309 were fatal accidents, 206 were serious injuries, and 86 were slight injuries and 507 were property damages. Statistical analysis was made on the collected accident data. The characteristics of accident in built-up (towns) and non built up (rural) areas were tabulated and analyzed separately. Fortysix per cent of the accidents occurred in built-up areas, which covered only 17.7 percent of the study road length. Pedestrian accidents and multiple-vehicle accidents were dominated in urban areas. Single vehicle non-pedestrian and rollover accidents were higher in non-built-up areas. Fifty-two percent of the accidents occurred at tangent and level section of the roads. This is associated with speed limit violation. The results of the study indicated that increases in accident rates were highly associated with gradient and sharp curves. ADT, numbers of x lanes and grade have positive relationships with accident rates i.e. the section with less traffic, lanes and grades resulted in less accident rates whenever these variables increased. Similarly, accidents were plotted using GIS software and nine accident black spots were identified. Out of these, six were on scheme roads and three were at intersections. Greater or equal to ninety percentile of accident rate for schemes and junctions were applied in order to select these dangerous sections. At ninety percentile, rate of accident was 3.459 Mvkm for scheme. Six road sections were found above either of the two accident rates. In case of junctions, ninety percentile was 0.728626 Mv junctions. Three spots had above the ninth percentile value and considered for in-depth study. The main causes of accidents at black spots were identified to be unavailability of proper pedestrian facilities, high volume of pedestrian traffic, drivers’ fatigue, lack of awareness of traffic rules and regulations, and violation of speed limit. In addition, densities of accidents per kilometer were verified as a function of access points in towns. Narrow bridges, inadequate sight distances at curves, road curvature, no proper traffic signs, and faded road markings are usually causes of accidents. Finally, low cost engineering measures are recommended to reduce the number of road accidents at identified black spots and other sections. However, the effect should be evaluated
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    Effect of Road Cross-Sectional Elements on Road Traffic Crashes And Injury Severity at Midblock in Addis Ababa, Ethiopia
    (Addis Ababa University, 2016-12) Daba, Alemu; Segni, Getu
    Road safety issues are the major economic, social and health problems, especially in the devel-oping country like Ethiopia. Road traffic crash is the result of complex interactions between the roadway, driver, and vehicle. This thesis was a study on the effect of road cross-sectional elements on road traffic crashes and injury severity at midblock segments in the city of Addis Ababa. Twenty midblock road segments were taken as samples based on a convenience sampling approach. Road data, crash data and traffic data were collected from selected road segments. The thesis has applied multi-nomial logit model to evaluate the safety impacts and injury severity of road cross-sectional el-ements at midblock segments. Poisson log linear model has also applied to investigate the rela-tionship between road cross-sectional elements and occurrences of road traffic crashes. In addi-tion, descriptive statistics was done in order to know road traffic crashes trends in Addis Ababa. A total of 2596 crashes was collected from Arada and Kirkos sub cities police stations of the Addis Ababa city and Addis Ababa police commission for period of three years from June 2012-July 2015. The results of this study reveals that there is a strong interdependency between road cross sec-tional element and road traffic crashes. The Type of median, sidewalk width, length of road segment and average daily traffic are significantly affect on injury severity at midblock seg-ments. In addition, median width, median height, number of lanes and log of average daily traf-fic have significant effect on road traffic crash occurrences. The modeling results of multinomi-al logistic regression indicate that painted medians have been positively associated with injury severity. Longer length of midblock segments, average daily traffic and narrow roadside width were found to be positively associated with injury severity. The result also indicates that shorter median height, wider median width, number of lanes and log of average daily traffic have posi-tive association with expected number of crashes. Transport authority should be expected to consider the result of the study in new projects, up-dating existing and developing new strategies of road cross-sectional elements design.