Study on traffic safety of road segment between urban close-quarter intersections based on traffic conflicts
Vehicles need to complete lane change operations at short distances by reason of its lane-changing demand,to generate serious traffic flow interference between two adjacent intersections,which is the key to cause traffic safety problems at urban road close-quarter intersections.In order to study the conflict severity of the interleaving section at the close intersection,a concept of intensity of traffic conflict(ITC)was de-fined.The spacing intensity of traffic conflicts(SITC)and the time intensity of traffic conflicts(TITC)are used to calculate respectively traffic-conflicts intensity of unit travel distance and unit travel time at two ad-jacent intersections.Traffic flow characteristics of interlaced sections was analyzed comprehensively at close-quarter intersections.Considering fully some key road parameters and traffic parameters at two adjacent in-tersections(such as:interval distance of two adjacent intersections,V/C,travel speed,etc.),the determi-nation threshold value of the time intensity of traffic conflict was proposed at close-quarter intersections by traffic microsimulation technology.The recommended value of the traffic conflict hazard level was proposed at two adjacent intersections by grey clustering method.Finally,by using traffic conflict intensity method to analyze the project example of adjacent intersections traffic conflict condition,and the engineering exam-ples,before and after the improvement of traffic conflict intensity is analyzed.Research results showed that spacing intensity of traffic conflicts(SITC)index had static attribute.The time intensity of traffic conflicts(TITC)index had dynamic properties,owing to contain speed parameters.The intensity of traffic conflict can be used to quantify the degree of conflict in interleaved sections and screen the sections with serious in-terleaved interference.The improvement measure of"left-turn lanes to set up on right side"could effectively reduce traffic conflict intensity of close stagger intersections with high turn-left traffic demand.