分离式立交.pptx

Types of intersectionnAt-grade intersectionnGrade separation or interchangenRoundabout(circle)At-grade intersectionRoundabout Interchange without ramps(分离式立交)Interchange with ramps(互通式立交)Introduction to intersection controlnBasic rule of road（基本通行规则）-n 1.Driver on the left yield to those on the rightn 2.Through traffic has right-of-way over turning movementsn 3.Sight distance should be met.(sight triangle 视距三角形)nSTOP and YIELD signs-n1.Two-way STOP sign(TWSC 二路停车)most popular-used control method at unsignalized intersections where major and minor roadways are met,the STOP signs are installed at approaches on minor streetvehicles on major street pass intersection without stopping,while vehicles on minor street have to stop first and then use gap to pass intersection Ranking of passing two-way stop control intersection n2.YIELD sign used at unsignalized intersections where major and minor roadways are met,the YIELD signs are installed at approaches on minor streets vehicles on major street pass intersection without stopping,while vehicles on minor street have to slow down first and then use gap to pass intersection The difference between STOP and YIELD is that drivers do not necessarily stop at intersection approach where YIELD is applied.YIELDsigninUKYIELDsigninChinaYIELDsigninUSAn3.Multi-way(Full-way or All-way)STOP sign（多路停车或全路停车）the STOP signs are installed at approaches on all approachesfirst come first pass is observed all-way stop control is used where same level roadways intersectThe STOP sign used in Beijing,Chinan4.Capacity of TWSCna.Priority of movements for TWSCnb.Conflicting volume（冲突流量）nc.Critical gap and follow-up time（临界可接受间隙与随车时距）nd.Potential capacity（可能通行能力）Raffs ModelnTraffic signaln1.Merit n(1)provide orderly movementn(2)enhance traffic-handling capacityn(3)reduce frequency and severity of crashesn(4)coordinate continuous movement along arterialn(5)protect pedestrians and bikers n2.Demeritn(1)excessive delayn(2)excessive disobedience of the signal indicationsn(3)encourage cut-through trafficn(4)increase of rear-end collisionsn 3.Warrants based on MUTCD(设置依据）n1.Volume principle(eight,four,and peak hours)n2.Pedestrian/biker principlen3.School crossing principlen4.Coordination principle（协调原则）n5.Crash principleNote:Engineering judgment plays key role.