AbstractThis paper describes a traffic behavior at merging (on-ramp) area in Baghdad city. The objective is to predict the acceptable and critical gap necessary for completing merging process in an on-ramp area for vehicles to enter the highway based on observed traffic data.Data were collected from two selected sites which had certain characteristics both operational and geometrical to fit the criteria needed for gap acceptance study which were presented hereinafter. These two sites were on-ramp sections at Mohamed Al-Qasim highway and the Army-Canal highway.Video-recording equipments were used to collect data. The observed data were analyzed, grouped, and processed using computer programs developed by the researcher for this purpose. Standard statistical analysis techniques were used to examine and analyze the observed data.Gap acceptance results are used to determine the critical gap. Critical gaps are playing main role to evaluate level of service and capacity at Highway merging sections. This study measures gaps in the major stream regarding to driver behavior for traffic stream in the merging area. It has been found that different types of drivers will accept different gaps, more aggressive drivers will accept smaller gaps and conservative drivers accept larger gaps.Keywords / Traffic behavior, Gap acceptance, Critical gap, Merging area, Highway capacity.
AbstractWhen drivers are approaching a signalized intersection at the onset of ayellow change interval, they must decide whether to stop or cross theintersection. This can be a difficult decision when the vehicle is locatedwithin the dilemma zone and the result is sometimes a rear-end crash due to asudden stop. Dilemma zone is defined as an area close to an intersection inwhich a vehicle can neither stop safely before the intersection nor clear theintersection without speeding before the red signal comes on. This research studiesthe driver behavior during the amber onset in the signalized intersection.One signalized intersection was selected in Damascus city to collect data forthis purpose. Data was collected using video recording technique. Data wereabstracted, processed and analyzed using programs developed for this purpose. Thestudy examined 226 drivers on the amber onset, 42.47% of them were found to beconflicted by the dilemma zone phenomenon. 51.25% of them conflicted withaccelerating, 42.5% who stopped abruptly, and 6.25% who passed during the redsignal.Key words: dilemma zone, amber onset, clearing distance, stopping distance
AbstractSelecting a design runway length is one of the most important decisions an airportdesigner makes. The length required to accommodate the most demanding airplanesanticipated to use an airport is a fundamental airfield design factor. This paperdescribes the important role which the runway length is playing in any proposedairport to be designed.Computer program named (RUNWLD) was developed during this researchperiod to determine the runway length depending on the Federal AviationAdministration (FAA) methodology. (RUNWLD) predicts the planned and basicrunway lengths for various mix of airplanes anticipated to use a proposed airports.The program was written in visual basic programming language. The dataused in this program is concluded from the charts, tables, and circular advisoryadopted by (FAA) methodology. The developed program (RUNWLD) is easy tooland user friend, in addition to that it save time while getting results comparing tothe traditional (FAA) method.Keywords: runway length, airport, airplane, FAA, program
Traffic control devices notify road users of regulations and provide warning and guidance needed for safe, uniform, and efficient operation of all elements of the traffic stream. Traffic control devices have been a part of the roadway system. Researches have evaluated various aspects of the design, operation, placement, and maintenance of traffic control devices. The purpose of this research is to develop a simulation model in order to evaluate the effect of overhead sign position on the traffic performance at exit of freeway weaving area. To achieve that subroutine was developed and added to FWASIM program to compute the sign position and compare it with the driver sight distance. Following that a proposed example represents an exit weaving area was examined with different traffic flow configuration (different percentages of link flow and on-ramp flow) with respect to no sign installed and other three sign positions. Results indicate that the average traffic speed is underestimated when there is no sign installed, while no significant effect is shown when the sign position is changed within the driver sight distance. In conclusion Guide signing is a critical element in the effective, efficient and safe operation of motorways and expressways. Signing issues must, therefore, be fully considered at the feasibility stage of any project.
AbstractThis paper describes a traffic behavior at merging (on-ramp) area in Baghdad city. The objective is to predict the acceptable and critical gap necessary for completing merging process in an on-ramp area for vehicles to enter the highway based on observed traffic data.Data were collected from two selected sites which had certain characteristics both operational and geometrical to fit the criteria needed for gap acceptance study which were presented hereinafter. These two sites were on-ramp sections at Mohamed Al-Qasim highway and the Army-Canal highway.Video-recording equipments were used to collect data. The observed data were analyzed, grouped, and processed using computer programs developed by the researcher for this purpose. Standard statistical analysis techniques were used to examine and analyze the observed data.Gap acceptance results are used to determine the critical gap. Critical gaps are playing main role to evaluate level of service and capacity at Highway merging sections. This study measures gaps in the major stream regarding to driver behavior for traffic stream in the merging area. It has been found that different types of drivers will accept different gaps, more aggressive drivers will accept smaller gaps and conservative drivers accept larger gaps.Keywords / Traffic behavior, Gap acceptance, Critical gap, Merging area, Highway capacity.