Browsing by Author "Fikadu Aschalew"

Now showing 1 - 1 of 1
  • No Thumbnail Available
    Item
    Traffic Safety Evaluation and Development of a Traffic Safety Prediction For the Approaches of Signalized Intersection Model Using Surrogate Safety Measures (The Case of Bole Sub-city)
    (Addis Ababa University, 2024-06) Fikadu Aschalew; Yonas Minalu (PhD)
    In developing countries like Ethiopia, particularly Addis Ababa, it has been noted that about 1,264 people have died from the year of July 2019 to June 2022 that was approximated 422 people die per year. This emphasizing that Addis Ababa city has highly affected by traffic accident with a significant loss of lives, serious injuries on individuals' well-being and property damage. Traffic safety studies and analyses were traditionally conducted using reports on traffic crashes. The drawbacks include failure to record the accident position, incompleteness, and underreporting of crash data and additionally the drawback of the traditional approach is needed many crash data for analysis, in order to draw any conclusions and take the appropriate corrective action. Thus, the microscopic traffic simulation was chosen for the evaluation of traffic safety. Eight signalized intersections with a combined total of 29 road approaches were selected and Simulation of Urban Mobility software were used to model the existing situation. Primary and secondary collected data are used as the input for the SUMO simulation to modify the default carfollowing and lane changing model with actual real data. Surrogate safety measures (TTC) for the selected study area were derived from Sumo output. TTC has a bell-shaped distribution with some skewness and Weibull distribution function were used to model the distribution of Time to collision distribution. After calculating the Weibull shape and scale factor parameter the Weibull cumulative probability for Time to collision below 2.5second were determined for all road approaches and used as dependent variables. Traffic safety evaluation was carried based on Weibull cumulative distribution. The roads from Jacross to Gerji meberat-hayel junction have the highest cumulative probability value of 0.779, or it has 77.9% chance of occurring potential conflict, while the roads from Latica bakery to Salithmhiret intersection have the lowest cumulative probability value of 0.164, or it has 16.4% chance of occurring potential conflict. A multiple linear regression were used to model the dependent variable, (cumulative probably for TTC below 2.5 seconds) and significant independent variables, (Traffic volume per lane and speed deviation). The coefficients of number of vehicles per lane is positive 0.00076186 indicated that for every increase of 100 vehicles per lane results the probability of the occurrence of potential conflict increased by 0.076 or 7.6% and the coefficient of speed deviation is 0.50114603 for every increase of speed deviation by 0.1 the probability of the occurrence of potential conflict increased by 0.0501 or 5.01%.