Browsing by Author "Tigist Eshetu"

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    Safety Performance of Speed Humps with Rumble Strips in Addis Ababa
    (Addis Ababa University, 2024-01) Tigist Eshetu; Getu Segni (PhD)
    With increasing urbanization, vehicle density on the roads has been increasing exponentially. Most of the vehicles and roads are designed for a particular speed. The improved roadway facilities have encouraged the drivers to drive fast in the urban roads. Excessive speed is a key risk factor for road accidents and greater severity of the injuries in the event of an accident. In such circumstances, it is very difficult to control a speeding vehicle unless some speed management measures are provided. In our city Addis Ababa speed calming interventions are implementing on the selected road segments of the city. The primary aim of this study is to evaluate the safety performance of speed humps with rumble strips in the context of Addis Ababa. To achieve this objective, two types of data were employed: primary and secondary data. Secondary data was utilized to gain insights into the characteristics of accidents on the specific road segments under study. In contrast, primary data was speed survey data, road segment length data and frequency of speed hump (number of speed hump and rumble strips) for the selected road segments. The speed survey data was thoroughly collected using ERA pavement design manual Volume I, 2013 Vehicle classification table. The Secondary data (accident data) covered the years 2014 to 2021 (2006 to 2013 E.C.) and was sourced from the Addis Ababa Police Commission and various sub-city police departments. The speed survey indicated that 85th percentile speeds were maintained below the speed limits of 30km/h by a considerable percentage at different points along the road segments: 46% 20 m before the speed hump, 92% at the speed hump, and 23% 20 m after the speed hump, across the total selected road segments. The T-test results for Traffic speeds are statistically significant for all variables and for all three pairs except Large Truck on before 20m of speed hump and after 20m of speed hump pair. Following the implementation of speed humps with rumble strips, the study shown a 31% reduction in Total Equivalent Accidents (EANs), a 24% reduction in total pedestrian accidents, a 54% reduction in pedestrian accidents involving crossing on the roadway, a 2% increase in pedestrian accidents involving walking straight and a 35% reduction in accidents involving public transport vehicles.Along with T-test results, it can be concluded that speed hump with rumble strips are effective in reducing accidents. When we can see the impact of speed hump with rumble strips on pedestrian safety the results also shows a significant change in the before-and-after study. With respect to pedestrian accidents by main activity speed hump with rumble strips the result also shows a significant change it can be concluded that speed hump with rumble strips are effective in reducing accidents Pedestrians Crossing on Roadway. This affirms that speed hump with rumble strips help in safe Crossing on Roadway. This means pedestrians can Cross relatively easier and are safer than Crossing on the roadway without speed hump with rumble strips. A T-test carried out on Pedestrians Accident Walking Strait in the before-and-after study indicated no significant change. Using results of this T-test, we can conclude that, speed hump with rumble strips, in this case, do not effect a significant change in reducing Pedestrians crashes Walking Strait. A T-test carried out on public transport study indicated no significant change. Using results of this T-test, we can conclude that, speed hump with rumble strips, in this case, do not effect a significant change in reducing public transport crashes on the road. Regression analysis used to produce the best relationship between density of speed hump and 85th Percentile Crossing speeds of the vehicles. Generally, the simple linear regression model that include one independent variable (85th Percentile Crossing speed) .The signs of the correlation coefficients in the regression model are as expected. The density of speed hump shows a positive correlation with 85th Percentile Crossing speed.