Developing Advanced Safety Evaluation Models Based on Unobserved Heterogeneity Across Different Signalized Intersections Using Bayesian Networks: A Case of Addis Ababa City

Abstract

Traffic accidents which has happened at the signalized intersections are one of the locations that the crashes used to occur compared to the roundabouts and any other roads because it is intersection. Nowadays, it’s the raised of epicenter of accidents and has given an alarming rate of increase of crash problems globally and so do here in Ethiopia, especially in Addis Ababa; the capital city. There has potential leaded factors that has contributed to the incremental of the issue such as improper functioning of the traffic light, lack of sign requirements at the intersection, pedestrian misunderstanding about the traffic lights, and so on. It has resulted in fatalities death, injuries, and property damage at least, and all of this has causes loss in the GDP of the nation. The main objectives of the study are to evaluated, analyzed and characterized the traffic accident parameters at the signalized intersections and draw a solution. Road signs at the intersections, traffic light elements, traffic accident report from the police station such as death, injury, crash and damage of human, animals, and property, AACRA district, document review from driver, consultant, and contractor were the source of data. The samples of the study talked about some of the signalized intersections in Addis Ababa City which has been selected by their influenced about the crashes while used prioritized based on their accident history. The necessary data for the study was collected from daily traffic accident records of the Addis Ababa Traffic Police offices of the Wereda’s and the intersection geometric design safety checking and recommendation from the consultant and contractor. Furthermore, the information needed was collected by interviewing traffic police officers. Majority of the respondents in Immigration, Meskel square and Mexico intersections are educated from diploma level to PhD degree level but in Piassa the majority are from secondary level to master degree level. Out of the all intersections, majority of the respondents are responded that they used to slow down their speed when approaching signalized intersections. So its they are educated people they claimed that the flow the traffic rule. Majority of the respondents in Immigration and Piassa intersections are aged from 15-30 years’ age class to 50-60 years’ age class but in Meskel square and Mexico respondents were between 30-40 years’ age class to 60-more years’ age class. Out of the all intersections, majority of the respondents are responded that the accidents happened during peak hours. Majority of the accidents happened during peak hours between 8:00 till 9:00 am with regard to immigration. In Meskel square it happened during afternoon peak hour from 5:00 am till 7:00 p, in Mexico it was happened between 12:00 pm till 2:00 pm and in Piassa it happened between during 5:00 pm till 7:00 pm. During these hours the traffic police should supervise and paid attention at signalized intersections traffic movement. Majority of the respondents have got accident at the intersection from hit in the rear side on the intersection to concert in collision inside the intersection, but in Piassa majority of the respondents had got accident at intersection from hit in the rear side on the intersection to hit us on the intersection. Majority of out of three intersections have respondents that they are pedestrians got incident while in Meskel square responded that the majority got incident are travelers. Out of all the intersections, majority of the respondents have agreed that the geometric design of intersection, traffic congestion, road side elements, pedestrian including non properly functioning traffic lights are the common factors that affect the safety of signalized intersections. Majority of the respondents are responded that the accident resulted in a fatal injury, injury and property JiT, Civil and Environment Engineering Department, Highway Engineering Stream Page IV damage only at Meskel square and Piassa, but in Immigration and Mexico resulted injury and property damage only. It should be followed the guidelines and maintain accordingly so it could minimize fatality injuries and property damages. Out of all the intersections, majority of the respondents are responded that the weather condition during accidents was rainy season. Majority of the respondents claimed that the road condition was wet when accident happened at Immigration, Mexico and Piassa but the road condition was dry when the accident happened at Meskel square. Out of all the intersections, majority of the respondents are answered that the accident happened during daytime where the light condition was bright. Out of all the intersections, majority of the respondents are regularly and occasionally crossing at the intersections. Majority of the respondents are responded when vehicles approaching at the intersection, they were approached in speed between 45-55 Kph to 55-65 Kph. Traffic laws should implement to safeguard drivers and pedestrians too. Based on the result of R software the studied signalized intersections found in the two sub cities of Arada and Kirkos and most of the signalized intersections were somehow in critical conditions according to Highway Manual Capacity and its recommended to increase the number of traffic lanes per direction, provide extra signal light for the approaching roads at intersection to reduce the traffic jam and construct pedestrian bridges passing over the intersections