Road and Transportation Engineering
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Item Toll Price Elasticity for the Addis Adama Expressway(Addis Ababa University, 2024-10) Nebiyu Nebabu; Fitsum Teklu (PhD)This research investigates the toll price elasticity of demand for the Addis Adama Expressway. The study aims to quantify how changes in toll prices affect traffic volume across various vehicle categories. Through econometric analysis using historical data from July 2019 to June 2023, the research incorporates key factors such as toll prices, fuel prices, GDP per capita, and external influences like security concerns and overburden restrictions. The findings show that toll price elasticity varies across vehicle categories, with short-term elasticities ranging from -0.25 to -0.51, indicating a negative but inelastic response to toll price increases. Over the long term, toll price elasticity becomes more pronounced, suggesting that drivers adjust their behavior over time in response to price changes. Fuel price elasticity was found to be unexpectedly positive, reflecting the cost-saving advantages of using the expressway compared to non-tolled roads. The research highlights the importance of integrating toll price elasticity into pricing strategies to optimize revenue while maintaining traffic levels. The results provide valuable insights for policymakers, supporting data-driven decisions on toll pricing and infrastructure development for the Ethiopian Expressway Network.Item Evaluating Functional Hierarchy of the Road Network Based on Trip Performance(Addis Ababa University, 2024-05) Rediat Kassa; Yonas Minalu (PhD)The quality and performance of road networks are significantly influenced by the functional hierarchy of roadways in metropolitan area. The functional hierarchy of roads affects the design and operation of road networks, as well as the trip performance. The primary objective of this study was to assess the functional hierarchy of various road network patterns to understand their influence on trip performance. The scope of study includes evaluating the functional hierarchy of road networks and their impact on trip performance within a urban area of a chosen cites on up to 6 kilometers within a four-square-kilometer section of the city. It has a significant contribution to forecast future trip performance and support proactive planning. Additionally, it provides practical recommendations to guide urban planning agencies in optimizing road network hierarchy, ultimately benefiting urban residents and commuters globally. Cities with higher junction densities, longer trip lengths, and a higher proportion of residential roads tend to experience longer travel durations within the network. This relationship modeled using a power function with logarism transformation which effectively captures the hierarchical structure of urban road networks. Interestingly, travel duration is significantly negatively affected by the presence of primary and secondary roads. Primary and secondary roads both show negative coefficients, indicating that higher proportions of these roads correlate with slightly reduced travel durations, likely due to their design for efficient travel. While the effect of primary roads is small but significant at p value of 0.00, secondary roads have a more substantial impact, emphasizing their importance in reducing travel time within the network. On the other hand, tertiary roads have a negligible and statistically insignificant effect on travel duration, suggesting that changes in their proportion do not distinctly influence travel time. However, residential roads demonstrate a significant positive relationship with travel duration with p value of 0.00, reflecting the duration of the trip has to be increased due to lower speed limit and existence of frequent stops typical in residential areas. Additionally, junction density showed a significant positive relationship with trip duration, with a p-value of 0.00. This indicates that as junction densities increase within the network, the trip duration also increases. The likely reason for this is that higher junction density implies more road connections from different directions.Item Improving Level of Service of Light Train, Pedestrian and Motorized Vehicle Shared – Space Intersection (Case Study of Saris Adey Ababa Intersection)(Addis Ababa University, 2025-01) Anteneh Zemedkun; Robeam Solomon (PhD)Providing of mass transport such as electric train in urban area is the best method to solve many transport problems such as safety, congestion, delay, free from air pollution, shortage of transport system supplies and others. However, provision of mass transport like urban light railway transit in congested city becomes a major cause for different problems such as excessive delay and queue formation and low performance of roads specially at grade crossing intersections and roundabouts that will be shared by pedestrian, light rail way and Motorized vehicle along the LRT. Accordingly, the main Couse for the problems are due to the light rail way builds parallel with center/median of road alignment and fragmented of the road area by fence, at grade crossing intersections become more congestion due to they were designed and build by considering only motorized vehicle and pedestrian without considering the new provided LRT, high concentration of U turns traffic due to lack of U turns in other locations and Un-controlled and high concentrated pedestrian crossing activities. Performance evaluation of the intersection under current traffic conditions was done during peak periods. The performance evaluation indicated that the approach delays of the intersection become over twelve minutes during peak periods. This research deals about improving the Level of Service of Light Train, Pedestrian and Motorized Vehicle Shared – Space at grade signalized Intersection, Case study Saris Adey Ababa at grade Signalized Intersection by propose alternative solution for the identified problems causes and to see if an acceptable performance can be achieved with-out provision of under pass and over passes (grade separation). In order to achieve this goal necessary data were collected at the study intersection. Formerly VISSIM simulation software was used to for designed and modeling. During the study Fixed Traffic Signal control with calibrated saturation flow, Transit Signal Priority, installation of Pedestrian fence and signals and diverting U turns to other locations are considered as alternative solutions. Performance evaluation such as maximum and average queue length, travel time, intersection delay and level of service was used as Comparing criteria under current and future traffic conditions. The best options for the study area are Fixed Traffic Signal control and Transit Signal Priority. Since, diverting U turns on other locations and provision of pedestrian signal were applied simultaneously with Fixed Traffic Signal control and Transit Signal Priority. Related to selecting the best alternative from Fixed Traffic Signal control and Transit Signal Priority. Fixed traffic signal control has less intersection delay of 72.9 sec/veh for vehicles however; it has additional delay on Tram and main traffic flow directions. On the other hand transit Signal Priority has higher intersection delay 79.9 sec/veh and additional approach delay on the opposite direction from Tram way but it has less approach delay for main approaches vehicles and for Trams. Transit Signal Priority with green extension and Red Truncation are preferred to be applied.Item Correlating Land-Use Characteristics and Parking Demand Conditions: A Case Study in Yeka Sub City, Addis Ababa-Ethiopia(Addis Ababa University, 2024-10) Dawit Berhanu; Yonas Minalu (PhD)The increasing car ownership in Addis Ababa is causing increased parking issues, leading to traffic and impacts. Current parking lots are high in traffic and population density but cannot meet city needs due to their location and capacity. A more effective parking system is needed, requiring a thorough examination of existing conditions and analysis of suitable locations for new parking lots. This study investigates parking conditions and land use characteristics in Yeka sub city, Addis Ababa, focusing on on-street parking areas and available off street parking. It assesses the city's current parking issue in terms of available supply and required demand in terms of land use. A Multi-Criteria Decision Analysis (MCDA) approach is used to solve the parking location selection analysis problem. The weightage of criteria used in the analysis is estimated, and potential parking solutions or site selections for new parking areas are identified using a combination of GIS & Analytic Hierarchy Process (AHP) techniques, identifying primary & sub-criteria, with a focus on travel absorption centers (land use), parking, and transportation as the primary criteria for selecting parking lots. The combination of GIS and AHP provides an efficient and optimal strategy for site selection & locating suitable parking locations. The AHP approach, when applied to criteria, established relative weights, whilst GIS enabled spatial analysis to discover ideal parking spaces. The MCDA results indicate that the most suitable parking lot. The study identifies accessibility to main roads as the criterion carrying the greatest weight (0.6472), while accessibility to church and mosque facilities (0.0205). The study area, primarily in the south-west of the sub city, has high suitability for public parking, with 0.924 square kilometers (1.057%) being extremely suitable. The remaining areas are suitable, moderately suitable, less suitable, and unsuitable covers 6.972, 9.52, 1.507, and 80.945 percent of the study area. To summarize, the integration of GIS with sophisticated aggregation and suitability analysis methodologies has a high potential to integrate and evaluate several geographical data sets at the same time, particularly in site selection studies. The study identified the suitable area for parking having 1.057% being extremely suitable with different suitability ranges. The study is a critical resource for sustainable urban management and decision-making, offering insights into future urban planning and identifying ideal parking lot sites.Item Travel Time Reliability to Evaluate the Performance of Bus Transport Service Along Major Corridors of Addis Ababa City(Addis Ababa University, 2024-10) Betselot Kassaw; Abel Kebede (PhD); Robeam Solomon (PhD)Travel time reliability (TTR) has been progressively considered an important measure of the performance of the transportation system. TTR is related to the travel experience and is significant to both users and public transport operators. The study investigates bus travel time reliability along major corridors in Addis Ababa, focusing on identifying key factors that influence reliability and proposing actionable improvements. As urbanization drives increased travel demand, public transport systems, particularly buses, are crucial for sustainable mobility. However, challenges such as traffic congestion, inadequate infrastructure, and unreliable services undermine their effectiveness. The main objective of the study is to characterize and develop predictive analysis of bus travel time reliability for a major corridors in Addis Ababa: Corridor 1 (Mexico to Haile Garment Square), Corridor 2 (Kara Kore to Wabi Shebelle Hotel/Mexico), and Corridor 3 (Megenagna to Derartu Square). The study aims to assess bus TTR, identify influencing factors and their impact on TTR of bus transport, and assess TTR from the users' perspective. A descriptive research method was used, combining quantitative and qualitative research approaches. Primary and secondary data were collected, including AVL (O D based) system data for travel time estimation and TTR modeling, as well as user perspectives gathered through interviews. A multiple linear regression model was applied to identify factors affecting bus TTR. Users were purposively selected at bus waiting stations along the corridors. Index based analysis with the planning time index was used to measure the reliability of the study corridors, and travel time pattern revealing that peak hours (AM(6:30 9:30) and PM(4:00 7:30)), and weekdays (Monday, and Friday) were particularly unreliable. The regression model fit, using those variables, yielded adjusted R squared values of 0.79 (79%) without interaction model and 0.8 (80%) with interaction for the study corridors. The analysis indicates that segment length, travel speed, dwell time, bus lanes, number of intersections, number of bus stops, bus frequency, time of the day, and day of the week are significant factors affecting bus travel time reliability across the corridors. Among interviewed users, 67% are unaware of the bus schedule, 50% acknowledged the impact of dwell time on bus TTR. 88% of respondents agreed on the effect of bus frequency and reported long waiting times, with 53% waiting over 30 minutes to get the next bus & 85% believe dedicated bus lanes reduce travel time. Users rated the day of the week and time of day as significant factors in TTR, with average scores of 1.58 and 2.1 out of 5, respectively, indicates the unreliability of travel time over the study corridors that supports the findings of the other numerical analysis. Therefore, the study recommends the need for tailored strategies, including optimizing bus schedules, implementing dedicated bus lanes, and improving communication and frequency, to enhance bus travel time reliability and user satisfaction. These insights offer valuable guidance for policymakers and transport authorities aiming to improve bus public transport services in Addis Ababa.Item Airport Runway System Performance Capacity Assessment: The Case Study for Addis Ababa Bole International Airport Runway System(Addis Ababa university, 2024-06) Alemu Weldemariam; Robeam SolomonThe airfield's capacity is a crucial aspect vital to airport transportation services, with the runway serving as a pivotal component influencing the airport's overall capacity. This study focuses on analyzing the capacity and demand of the airfield particularly the runway at Addis Ababa Bole International Airport (AABIA). Flight data, encompassing daily operations on various sampled dates under different weather conditions, aircraft compositions, seasonal variations, across multiple years, and, during peak and non-peak hours has been meticulously sampled, modeled, analyzed, and filtered to identify the maximum hourly capacity and the potential capacity constraints factors. Two method of capacity analysis have been used. The first method is Federal Aviation Administration (FAA) Advisory Circular AC 150/5060-51. Using this method, 40, 50, and 60 Percent Arrival capacity was calculated and this capacity figure identified the general status of the capacity compared to the current demand and deep understanding achieved. In the Second method (ICAO), aircraft separation rules for arriving and departing aircraft were taken into account. Based on the nature of the aircraft fleet mix statistical analysis Poisson Joint cumulative Distribution for leading and following aircraft was computed for all possibilities. After getting the capacity at four points of arrival departure combinations joining those four points on the arrival vs departure graph serves as the capacity curve or capacity envelope. By inserting the actual current arrival vs departure data in the same graph of the capacity envelope, the current demand compared to the capacity is identified. Conversely, the impact of runway occupancy time and actual runway demand on departure delays has been evaluated using linear regression. The study results indicate that actual demand has no effect on departure delays. However, the duration of runway occupancy has a slight influence on delays, suggesting that the current demand has not yet reached the runway system's capacity. Therefore, the delays are caused by the factors which are not related to the runway system. The general conclusion is reached that the capacity of the runway system is higher than the current demand indicating that at this point the Runway system is not a major factor in any current delays in aircraft operations. In other terms, the findings reveal that the current runway capacity can sufficiently meet the current demand. Despite the capacity of the runway system exceeding demand during peak hours, the study indicates that the average runway occupancy time is higher compared to similar hub airports such as London Gatwick and Mumbai airports which are busier airports that have a similar runway system and handles a mix of Heavy and Medium aircraft similarly, indicating that proactive measures is required to enhance the capacity of the runway system to ensure that the runway system will accommodate the future demand without causing excess delays.Item Assessment of Traffic Congestion Analysis Measures in Addis Ababa City (A Case Study of Mexico Square to German Roundabout Road Segment)(Addis Ababa, 2024-06) Samuel Endale; Bikila Tekelu (PhD)One of the most prevalent issues with urban transportation systems is traffic congestion. When there is a disruption in the regular flow of traffic, it leads to a decrease in speed, a delay in travel, and a substandard quality of service, this is known as traffic congestion. Depending on the causes, traffic congestion can either be recurrent or non-recurrent. Recurrent congestion is brought on by transient signal changes, capacity violations, and excessive traffic demand. On the other side, unusual events like work zones, severe weather, and other occurrences could cause non-recurring congestion. Numerous methods for evaluating traffic congestion have been devised, taking into account various factors such as speed, travel duration, frequency of delays, quality of service, and other congestion indicators. The level of service method and travel time-based measurements, which are the two categories into which the already existing congestion measures were divided, then examined within this research. The road segment Mexico square – German roundabout was chosen from the city’s core area and three road sections were selected from this segment to achieve the stated objective. The relevant data was manually collected by the researcher from selected segments, utilizing equipment appropriate for the study's objectives. The results showed the travel time based measures showed variations in the congestion state while indicating a similar congestion trend during peak and Off-peak hour for the Africa union – Pushkin square and Mekanisa Abo – Mekanisa road sections while showing a uniform congestion state for the Mekanisa – German Roundabout Road section. The capacity for the level of service was modeled using three traffic flow models, the Greenshields, Greenberg and Underwood model. The result indicates the underwood model better explained the data compared to the other two models. And, the advantages and disadvantages of the measures used have been discussed from the results.Item Reliability Distribution Modeling for Bus Dwell Time and its Contributing Factors: A Case Study in Selected Routes of Addis Ababa City(Addis Ababa University, 2024-04) Asmamachew Yilak; Girma Gebresenbet (PhD); Hilina DemekeThe initial point of contact between the passenger and the passenger service is at the bus stop. All buses in Addis Ababa City now operate in mixed traffic with no signal prioritization, with the exception of BDL (Bus Dedicated Lane) on a few chosen routes. Bus stops are significant components of the Public bus system, and the way they are run has a significant impact on the network's overall service level and transit effectiveness. The aim of this work was determining the most influential factor on dwell time and the likelihood of dwell time occurrence at stop. Quantitative and qualitative data were gathered for a study on bus dwell times at stops, with quantitative data obtained from bus stops and qualitative data from passengers. Manual field data collection was conducted due to the lack of Automatic Passenger Count (APC) and Automatic Vehicle Location (AVL) data. To ensure accuracy, data collection was repeated for three days at each stop and time frame, three bus type, and the averages were used for dwell time determination. Directionality was considered, categorizing bus stops into upstream, stop, and downstream sections. The lengths of these sections were determined based on observed bus maneuvers within a 10-meter radius during a pilot survey. Video recording and direct transcription onto paper sheets were used to collect data for a specific bus. Only buses stopping at designated stations within the specified range were considered for the study. The data were analyzed using a statistical model and the probabilistic method of analysis. The research successfully achieved its stated objectives, contributing to a novel approach for evaluating dwell time. The author developed two models to identify the most significant factors affecting bus dwell time specifically, the Gaussian and Weibull regression models. The Weibull regression model demonstrated superior accuracy and a better fit for predicting bus dwell time, with a significantly lower RMSE (0.075) and an Adjusted R-squared of 92.63%, compared to the Gaussian regression model (RMSE: 3.93, Adjusted R-squared: 93.00%). Moving to specific coefficients in the Weibull regression model, factors such as No_aligt. Weibull (Number of alighting), Alig.Weibull (Alighting time), Board.Weibull (Boarding time), Idle.Weibull (Idle time), No. Boa.Weibull(Numbers of Boarding), Odd.pen.Weibull (Odd. Penny Weibull), Re.boa.Webull(Re-boarding passengers), Accel.Weibull (Acceleration time), and Far side (Far side stop location) exhibited a statistically significant effect on bus dwell time at stops. However, the location of the far side stops and the time of day had no effect on dwell time. The combined effect of stop location and bus type did not show statistical significance (p-value: 0.845), surpassing the conventional threshold of 0.05. However, analyzing the variables individually revealed a significant difference between stop type location and bus type in relation to dwell time. Specifically, Alliance buses exhibited longer dwell times compared to single Sheger and Anbessa buses.Item Assessing the Socio-Economic Impact of Traffic Congestion in Addis Ababa (Case Study: welete to Total)(Addis Ababa University, 2022-02) zuleha Jemal; Bikila Teklu (PhD)Addis Ababa is the cities which is undergoing in a fast urbanization and facing traffic congestion in significant manner. It has both social and economical implication on the peoples of the country. The socio-economic impact of traffic congestion comes in many forms, such as increase stress and fatigue, constraint social relation, increase accident and incident, increase transport cost, difficulty to estimate travel time, missing appointment and late delivery, block for emergency vehicles, diversion to the local road, and health problem. This study assesses the socio-economic impact of road traffic congestion in Addis Ababa city in case of Welete-Total road segment. Primary data collected using questionnaires and filed visit. The data collect from questionnaires analyze using Statistical Package for Social Sciences (SPSS) software to assess the cause, impact and solution of traffic congestion at study area. And the data collected from field visit of the three major intersections at the road segment was used for Traffic volume and Spot Speed analysis using Excel spread sheet. And performance Analysis of the intersections was done by considering delay, queue and LOS using VISSIM 9 software. The level of service result of Ayertena signalized intersection, Zenebework Roundabout and Total Turbo Roundabout is LOS-F, LOS-B and LOS-D respectively. The estimated Total congestion cost of the all three intersections based on delay cost and change in vehicle operating cost at morning peak hour is 879,968.45 ETB. To enhance performance of Total 3kutr mazoriya Turbo Roundabout, this study proposed engineering solutions is signalizing the roundabout by maintaining its current geometry as it is. Signal timing design and approaching saturation flow rate were computed by using HCM 2010 and coded in vissim software to do performance analysis. The result showed significant reduction of delay from 72.59 seconds to 17.84 seconds and increase Level of service of the roundabout from LOS-D to LOS-B.Item Analysis and Modeling the impact of Road Network Typology on the Macroscopic Fundamental Diagram(Addis Ababa University, 2024-06) Tilaneh Tesfahun; Yonas Minalu (PhD)The population and traffic in cities increased consistently due to the increase in urbanization, economic growth, and increased welfare. This trend necessitates changes in city road network structure in order to satisfy the growing travel demand. This research investigates the relationship between road network typology and the macroscopic fundamental diagram (MFD) in Addis Ababa city road network. The macroscopic fundamental diagram (MFD) refers to the relationship between density, flow, and speed at the network level. The macroscopic fundamental diagram is important in the field of transportation and urban planning. By illustrating the relationship between travel speeds, traffic flow rates, and vehicle density in an urban setting, it gives a macro-level understanding of how urban transportation networks work. The objective of the study is to understand how different road network typologies affect the overall traffic flow and the macroscopic fundamental diagram. Sixty-one 2km by 2km road networks extracted from OpenStreetMap were analyzed using simulation of urban mobility (SUMO) with consistent Origin-Destination (OD) data. The study used geographic information system (GIS) software to gather road network typological data (i.e. road network connectivity indexes, network density, primary road proportion, and trafficable area). Whereas, the maximum flow data were extracted from a simulation of urban mobility output. An exponential regression model was developed to assess the impact of network typological factors on the MFD. The regression model yielded significant results, with an adjusted R square value close to one, indicating a strong correlation between network characteristics and macroscopic traffic flow dynamics. Factors such as alpha, degree centrality, primary length proportion, and network density were found to be statistically significant in influencing the aggregated maximum flow. The study aims to provide insights into how road network characteristics influence macroscopic traffic flow dynamics, aiding in the optimization of transportation systems and urban planning strategies. The findings will offer valuable information for urban planners and decision-makers to enhance transportation efficiency and network design in Addis Ababa City. The research highlights the importance of understanding MFD for optimizing transportation systems and suggests a shift towards holistic urban traffic management strategies based on macroscopic variables for sustainable urban development.Item An Investigation of The Impact of Sidewalk Vendors on Pedestrian Safety and Pedestrian Utilization of The Sidewalk: A Case Study in Yeka Sub City, Ethiopia(Addis Ababa University, 2024-03) Abel Seifu; Getu Segni (PhD)Ethiopia's can benefit from effective NMT, particularly walking. The city's rapid population growth and migration have led to street vending activities, causing obstructions and pedestrian safety threats. This negatively impacts the city's economy, reducing pedestrian service and increasing delays (Sahani et al. 2017; Bahiru, 2019). Traffic accidents cause 1.19 million deaths annually in the world, with pedestrians, cyclists, and motorcyclists being the most vulnerable (50%). Low- and middle-income countries account for 92% of fatalities, despite having 60% of the world's vehicles (WHO, 2023). Ethiopia's road traffic deaths increased by over doubled between 2007 and 2018 (from 2,161 to 4,597), with Addis Ababa experiencing high pedestrian fatalities (Priti Gautam et al. 2020). The study investigates the impact of sidewalk vendors on pedestrian safety and Pedestrian Utilization of the Sidewalk in Yeka sub-city of Addis Ababa, Ethiopia. It uses analysis techniques like ordinal logistic regression, Conjoint Analysis, and Pedestrians' Preference Score to understand perceived safety and predict sidewalk usability. Primary data was collected through questionnaires, surveys, and field observations, while secondary data was gathered from various sources, including Addis Ababa city police commission crash data. The study investigates pedestrian safety in Yeka sub-city sidewalks using an ordered logit regression model, issues vendors and examining relevant inputs. It finds that vendor activity negatively affects safety, while sidewalk adequacy indirectly enhances it. Factors like PLOS and surface condition significantly impact perception, with improved walking surfaces and PLOS variables improving safety. Encroachment on roadways also negatively affects safety, with sidewalks limiting walking opportunities. Factors like sidewalk width, age, frequency, purpose, education, walking distance, and time also influence perceived safety. The study uses conjoint analysis to generate part-worth utility and relative importance values for each attribute level in a hypothetical profile then Total Utility Value was determined. It uses pedestrians' preference score to measure evasion using sidewalks. Key sidewalk attributes affecting walkability, such as width, flow rates, obstructions, and sidewalk condition, are identified. The survey shows walkable width is the most important attribute, with 1.5m-2.5m desirable.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%.Item The Effect of Small Vehicles’ Modal Shifting to Bus on The Performance of Some Selected Roundabouts in Addis Ababa(Addis Ababa University, 2024) Rahel Birhanu; Robam SolomonRoundabouts are the circular island for vehicles movement from different direction to change movement directions, paths and for crossing by counterclockwise movement around the circle. The imbalanced increase traffic volume will result traffic congestion. The main determinant for performance is traffic volume and the geometry of the roads. Many intersections and roundabouts in Addis Ababa city suffer from poor traffic management, leading to congestion and delays. To address this issue, the Addis Ababa Traffic Management Office has converted most roundabouts into signalized intersections. Additionally, the Ministry of Transport has developed a 10-year plan aimed at increasing the share of urban mass transport services from 34% in 2020 to 70% in 2030. This plan is expected to greatly improve the efficiency and quality of transportation in the city. On this study the performance analysis for the selected areas was performed using PTV Vissim 9 software program. To evaluate the performance of roundabouts, three different approaches were followed: PCU modal shift, unit change modal shift, and carpooling modal shift. The result of the analysis on the baseline scenario for Urael, Lamberet and Salitemeheret roundabout is LOS F, F and F respectively. Then the LOS for Urael and Lamberet roundabout upgraded to LOS B and E respectively and still LOS F for Salitemeheret roundabout with the PCU modal shift path and the LOS of those three roundabouts changed to LOS B, F and F respectively with unit change shift and carpooling modal shift paths. Based on the evaluation results of the Urael roundabout, the vehicular delay time in the baseline scenario was 51.73 seconds. However, in the modal shift scenario, the vehicular delay time ranged from the highest of 51.73 seconds to the lowest of 13.45 seconds and the upgrade was a result of 74% delay reduction from baseline scenario. Similarly, at the Lamberet roundabout, the vehicular delay time was 78.87 seconds in the baseline scenario while in the modal shift scenario; it varied from the highest of 88.90 seconds to the lowest of 42.39 seconds and the upgrade was a result of delay reduction with 46% from the baseline scenario. Lastly, at the Salitemeheret roundabout, the vehicular delay time in the baseline scenario was 92.54 seconds but in the modal shift scenario, it ranged from the highest of 92.54 seconds to the lowest of 27.80 seconds and the upgrade was a result of delay reduction with 70% from the baseline scenario. When the LOS upgrade the travel time was decreased, vehicular traveling speed, queue length, vehicles stop, fuel consumption and the emission was decreased. Finally, this research has significant to determine the preferable modal shift and it will provide information for Ministry of Transport, Traffic Management Office and other concerned group.Item Volumetric and Performance Comparison of Field Produced Lab Compacted and Laboratory Produced Lab Compacted Hot Mix Asphalt Mixtures: A Case Study On Three Road Projects In Addis Ababa(Addis Ababa University, 2024-05) Yonas Dessiye; Robeam Solomon (PhD)The aim of this study was to compare the mixture volumetric and performance of lab produced lab compacted and field produced lab compacted asphalt mixtures in terms of Marshal flow and stability (for Marshal samples), rutting and moisture sensitivity together with checking bitumen and aggregate qualities. In doing so, loose asphalt mixtures ready to be paved was collected from selected road sites in Addis Ababa and taken in to the laboratory. Raw materials like aggregate, filler and bitumen were also collected from their respective quarry sites and batching plants in order to produce laboratory control samples. In addition the batching plants of the study areas were assessed for age and capacity. The bitumen and aggregate were all found qualified with regard to design specifications on the case study areas. Those raw materials were then mixed in the laboratory by keeping the projects‘ aggregate gradation and optimum binder content. Three road projects were involved in this study, namely Kality-Tuludimtu road project, Entoto-Kotebe Access road project and Imperial Kadisco Intersection project. The first two projects were designed using Marshal method and third project was designed using the Superpave method. The field and laboratory produced Marshal mixtures were compacted with Marshal compaction in accordance with design traffic level and the Superpave samples were compacted to Nin, Ndes and Nmax by a SGC machine according to field traffic level. Understanding the performance and volumetric difference among field produced and lab produced Marshal and Superpave samples is used to mitigate the economic impact on the paving industry and take further implementations. Marshal samples were evaluated with indirect tensile strength, stability and flow. The Superpave samples were evaluated with indirect tensile strength and wheel-tracking test. On the way to these tests, the mix volumetric of both Superpave and Marshal samples were determined. The result of this assessment shows that, field produced Marshal samples show an average increment of 3.7% in bulk and theoretical maximum specific gravities while field Superpave samples found 0.2 times more than lab produced samples; which were manifested in the mix volumetric variation. The Marshal flow and stability test results also proven the difference between lab and field samples. Indirect tensile strength test results for Marshal laboratory mixtures were found 1.6 and 2.15 times more in accordance with field samples. The field Superpave samples, however show an improvement on indirect tensile strength test. The wheel-tracking test was also applied to Superpave samples to evaluate the rutting performance of the field and lab samples. The laboratory samples protected their structural integrity during the wheel loading duration and gave 24% lesser maximum rut depth than field samples. With the entire assessments of this study, laboratory samples of Marshal and Superpave samples proven better performance than field samples.Item GIS-based cycle Network Planning and Evaluation Of Home to School Trips: A Case of Addis Ababa City, Ethiopia(Addis Ababa University, 2023-11) Zewdu Habte; Yonas Minalu (PhD)A city's quality of life is worsened by increasing usage of motorized transportation and accompanying infrastructure, which results in traffic congestion, environmental pollution, and traffic crashes. To improve mobility on those streets, reduce traffic congestion, improve public health, and make the city more environmentally friendly, non-motorized transport like cycles should have given more attention to the improvement of facilities and the number of cycle users. Engineers and planners in Ethiopia don't, however, have a common procedure for figuring out whether a road is suitable for allowing cycles to operate effectively. As a result, certain circumstances render the transportation system irreversibly unsustainable. In order to improve mobility, a lot of time and effort is put into developing a GIS-based cycle network-planning tool for comparison with the actual state of the planned cycling network. In the example of Addis Ababa city, this study focuses on using a new, highly dependable cycle network design and analysis for home-to-school activities. Utilizing ArcGIS Software which is spatially compatible for network planning activities, the study's methodology was combined with an analysis of the road network utilizing the best route, service area, and closest facility criteria for residents (incidents) and schools (facilities). The data for network development was primarily gathered through site investigation and accounting the ground truth from Google Earth Pro in collecting coordinates of selected Sample of Residence and school locations of the Study area in Addis Ababa city as well as converting to the local coordinate system to fit with the Road network of the Study Area. The study makes use of secondary data, such as the road network from the Addis Ababa City Government Plan and Development Commission (.Shp), as well as reports from various agencies. The closest facility analysis location with the shortest total travel time was RDLocation 7( Shola condominium) -SCL 27(New grand school) where the travel time was 0.309 minutes, and the location with the longest total travel time was RDLocation 4( signal condominium) -SCL27( New grand school), where the travel time was 1.696 minutes. Based on analysis, this study's best facilities network has a total length of 13028.36 m and a total minutes of 202.46. The network service area analysis extension tool used in this study also satisfies the case study area.Finally, the present study evaluates the results from the logical network analysis with the planned cycle network and also with the normal network condition of the road network.Item GIS-based cycle Network Planning and Evaluation Of Home to School Trips: A Case of Addis Ababa City, Ethiopia(Addis Ababa University, 2023-11) Zewdu Habte; Yonas Minalu (PhD)A city's quality of life is worsened by increasing usage of motorized transportation and accompanying infrastructure, which results in traffic congestion, environmental pollution, and traffic crashes. To improve mobility on those streets, reduce traffic congestion, improve public health, and make the city more environmentally friendly, non-motorized transport like cycles should have given more attention to the improvement of facilities and the number of cycle users. Engineers and planners in Ethiopia don't, however, have a common procedure for figuring out whether a road is suitable for allowing cycles to operate effectively. As a result, certain circumstances render the transportation system irreversibly unsustainable. In order to improve mobility, a lot of time and effort is put into developing a GIS-based cycle network-planning tool for comparison with the actual state of the planned cycling network. In the example of Addis Ababa city, this study focuses on using a new, highly dependable cycle network design and analysis for home-to-school activities. Utilizing ArcGIS Software which is spatially compatible for network planning activities, the study's methodology was combined with an analysis of the road network utilizing the best route, service area, and closest facility criteria for residents (incidents) and schools (facilities). The data for network development was primarily gathered through site investigation and accounting the ground truth from Google Earth Pro in collecting coordinates of selected Sample of Residence and school locations of the Study area in Addis Ababa city as well as converting to the local coordinate system to fit with the Road network of the Study Area. The study makes use of secondary data, such as the road network from the Addis Ababa City Government Plan and Development Commission (.Shp), as well as reports from various agencies. The closest facility analysis location with the shortest total travel time was RDLocation 7( Shola condominium) -SCL 27(New grand school) where the travel time was 0.309 minutes, and the location with the longest total travel time was RDLocation 4( signal condominium) -SCL27( New grand school), where the travel time was 1.696 minutes. Based on analysis, this study's best facilities network has a total length of 13028.36 m and a total minutes of 202.46. The network service area analysis extension tool used in this study also satisfies the case study area.Finally, the present study evaluates the results from the logical network analysis with the planned cycle network and also with the normal network condition of the road network.Item Passenger Car Equivalence Under Several Upgrade Road Conditions (For Cases under Addis Ababa City)(Addis Ababa University, 2023-10) Alemzewed Sete; Bikila Teklu (PhD)In developed countries, extensive studies have been conducted to estimate passenger car equivalence (PCE) values under various road geometry, traffic characteristics, and lane width conditions. However, it is important to note that these PCE values may not directly apply to local conditions in Ethiopia since Ethiopia possesses a distinct traffic environment characterized by heterogeneous traffic conditions, diverse road geometries, and unique traffic characteristics. Therefore, relying solely on PCE values derived from studies in developed countries may not accurately reflect the specific conditions and dynamics of Ethiopia's transportation system. There is also a lack of comprehensive understanding regarding the influence of vehicle characteristics in different road configurations in Ethiopia, particularly with respect to PCUs. The Highway Capacity Manual (HCM) of 2010 suggests treating road segments with steep grades separately, given their unique conditions. This study focuses on estimating Passenger Car Unit (PCU) values for six vehicle types, considering variations in traffic volume, road grade, and road lane configurations in Addis Ababa, Ethiopia. Data collection, conducted between 4:00 am-10:00 pm over four hours on Tuesday, Wednesday, and Thursday, covering both one-lane and three-lane roads in four selected areas. The utilization of an Artificial Neural Network (ANN) model aids in training and predicting speed, while the Dynamic PCE method determines PCE values. Multiple regression analysis established a mathematical relationship between PCE, vehicle type, road grade, and vehicle speed using SPSS software. Results indicate varying PCE values for different vehicle types on one-lane and threelane urban roads at different grades. Notably, heavy vehicles exhibit higher PCE on one-lane roads, while buses and medium trucks show consistently higher PCE on three-lane roads. In segments with high road grades, there is an inverse speed impact, starting high and concluding low in three-lane segments, and the inverse relationship continues in one-lane segments, starting with low speed and concluding with high speed on a high uphill grade. Moreover, the obtained PC values surpass those presented in the HCM, signifying their suitability for reflecting the current traffic conditions in the studied locality.Item Evaluation of U-turning Road Traffic crash at Median Opening In Yeka sub city, Addis Ababa(Addis Ababa University, 2023-06) Hailu Amare; Getu Segni (PhD0Road traffic crashes occur as a result of several factors associated with the traffic systems, such as road users, road environment and vehicles. Despite having low road network density and vehicle ownership, Ethiopia has a relatively high number of road traffic accident records. Consequently, Ethiopia is one of the nations across the globe with the highest fatality rate per vehicle. The research was based on the collected data from Traffic Police Office in year between 2017/18 and 2020/21. Field observations were also carried out to collect the required of primary data to be performed as complement to accident analyses. In this research Statistical analysis (multinomial logistic regression analyses) was used to decide the relationship of dependent and independent variables This study tries to analyze the traffic crashes, and develop a preventive strategies and possible counter measures for the route selected as black spot area. The aim is to provide users with an understanding of the major causes of traffic crashes and present using several Statistical tools. In Yeka sub-city the road traffic crash become serious that many people lost their lives, injured and loss of properties. U-turn at median opening traffic crash was one of the most frequently occurring collisions by different causes and area of sub city. Human error, road environment and vehicle factors are main causes of road crashes. In the study area related to driver’s errors were 91 percent, poor weather conditions 6 percent and other factors take about 3 percent. The result of the study showed that higher traffic accident cause by male drivers compared to female drivers. Also the study finds the age groups of 18-30 were mostly affected age of drivers. From the day of the week Tuesday was the highest traffic accident were recorded. And also accidents varies throughout the time of the day, hence times of the day from 7:00am-8:00am, 12:00am-1:00am, and 5:00am-6:00am were the highest accident were recorded. Improper design of cross-sectional elements like narrow Median width, narrow median opening lengths, lack of speed limit and lack sufficient sight distance on the road has been contribute own share for road traffic crashes in sub city.Item Performance Evaluation of AALRT Level Crossings along North- South Line Case study on Adey Ababa and Sebategna Level Crossings(Addis Ababa University, 2023-04) Lemmi Gurmessa; Bikila Teklu (PhD)Railway grade crossings are the intersection of two modes of transportation with very different physical and operational characteristics. There are many variables factors that influence a motorist’s ability to react appropriately at grade crossings. These factors include the information available as the driver approaches, the crossing and human factors such as competing decisions, distractions, and impaired driving. This paper is intended to study the performance evaluation of AALRT Level crossings where road traffic (Road Vehicles), Pedestrians and LRT vehicles (Trains) are computing for crossing each other along the North –south line. This area is one of the important places that belongs to both the rail line and the road as well the bottle neck for the operation of trains. Performance evaluation using Average control delay and Level of service of level crossings were the main topic covered with in the paper. Primary data (Traffic Volume data at crossings) have been collected using Video camera for Six hours at each level crossings. Based on the collected Traffic volume, the traffic distribution to each direction has been counted carefully to minimize the error including pedestrian’s volume. Sidra Intersection 8 software along with Highway capacity manual 2010 (HCM 2010) have been used to evaluate the Performance of theses Level Crossings at 3, 6, 10,15- and 20-minutes’ headway of Addis Ababa Light Rail Transit (AALRT) operation. Intersection models with different Conditions have been considered to see the effects of the presence of pedestrians, Light rail Vehicle (LRV) Frequencies and the type of Traffic Control (Signaling and Yield Sign control). According to the results the presence of pedestrian is sounder in Yield control methods than the Signal control for the same Intersection geometry, LRV frequency and Traffic Flows. Comparison of the Signaling and Yield Control results at the existing traffic condition and Level Crossings geometry conditions shows that Signaling control will perform better than the Yield control. According the result of both from Signaling and Yield control models, both level crossings will not perform at LOS D (Target LOS) at the existing Geometric and Traffic Flow conditions. Finally, the Level crossings were modelled with traffic movement and Geometric modifications under signaling control and the result shows that these level crossings will perform at least at LOS D if the recommended modifications have been set accordingly.Item Evaluating the Major Causes of Road Traffic Accident Occurrence Related to Geometric Design Elements of Addis Ababa -Debre Brehan Trunk Road(Addis Ababa University, 2023-06) Mahder Bekele; Getu Segne (PhD)Road safety issue becomes a worldwide concern specially for developing countries these days since it results in a serious social and economic problems. Several Geometric design and safety research have been undertaken by aiming to improve roadway designs and providing a forgiving roads to the road users. The impact of geometric design factors such as horizontal and vertical curves, lane width, shoulder width, super elevation, median width, curve radius, sight distance, and others on safety has been investigated. However, the relationship between geometric design components and accident rates is remained complicated and unclear since there is a scarcity of data on the association between geometric design features and the accident rates. This study's primary objective is to investigate the geometric design related factors that influence the frequency and severity of traffic accidents on the Addis Ababa–Debrebrehan Trunk Road, by considering design elements such as the average degree of curvature, average gradient, number of lanes, lane widths, shoulder widths and types, median widths and types, total surface width, rural-urban classifications, speed limits, and the presence of structures. As-built drawings, findings from an inventory assessment of the roads, information on traffic volumes, and traffic accidents reports from six consecutive years have been collected for this investigation. Empirical and descriptive statistical analysis models have then been used to analyses the data. In order to analyses the count/discrete outcome variable of traffic accident frequency, a generalized linear model family of Negative Binomial Regression model has been used and Ordinal Logistic Regression Model with Probit link function for severity analysis, by considering geometric design features as continuous and categorical independent variables. As a result, a total of 1192 traffic incidents were recorded and used for evaluation, of which 274 resulted in fatal, 293 in serious injury, 182 in minor injury, and 443 in property damage only crashes. Thus, the model for accident frequency analysis has demonstrated a convergence value for the segment length, average daily traffic, median width, number of lanes, outside shoulder width, average degree of curvature, average gradient, and speed limit. In addition to the frequency model, the severity analysis model has also reached at convergence for the vertical gradient, degree of curvature, availability of structures, median width, surface width, right and left shoulder widths and availability of median barrier.