intersection in roads by malyar talash
TRANSCRIPT
INTERSECTION
Prepared by: Zakir Hussain FarahmandUnder the Supervision OF: Eng. Malyar Talash Road Design Engineer/NRAP/MoPW Kabul-Afghanistan Emails: [email protected] [email protected] Mob: 0093786575033
Introduction: Area which two roads cross each other. Key Feature of Street: Focus of Activity: concentration of
travel Destinations. Conflict Movement: Motor vehicle,
bicycle, pedestrian Traffic Control: Cause Delay Capacity: reduced by delay
Terminology of Intersection
Requirement of Intersection 1. Safe and convenient operation for all road users, including
cyclists and pedestrians 2. Adequate capacity for peak-hour demand on all
movements; 3. Adequate visibility of conflicting traffic; 4. Minimum delay and disutility to all road users 5. Proper drainage of storm water; 6. Necessary regulatory, warning and informational
messages for all road users;
Basic Element Consideration Human Factors: like Decision and Reaction time,
pedestrian use and habits and etc. Traffic Consideration: like Design and Actual Capacities,
Vehicle speeds, variation of movement, Bicyclic and pedestrian movements and etc.
Physical Elements: like Vertical alignments at the intersection, Sight distance, Angle of the intersection, Conflict area, Geometric design features, Lighting equipment, Safety features
Economic Factors: cost of improvement and energy consumption.
Basic Concept of IntersectionMovement: in a four leg intersection 12 movements exist.(see the figure}
2- Type of Movements: Unopposed Movement: Don’t be any other movement in
opposite. Like Movement on one side. Protected Movement: Red signal protect it from opposite
conflict. Left Turn Permitted Movement: By considering priority right turning
is allowed. Like Right Turning in respect to Pedestrian footfall
Prohibited Movement: sometimes in peak hour left turning is proscribed.
Turning Conflict PointsDiverging: points which separate from a road.Merging: Points which movement approach to a roadCrossing: Points which two opposite movement cross each other.
Signalized intersectionPhase: Unit time which control one or more similar movements come one after another.
Ring Diagram: Group of phases which separate crossing movements.
Red Clearance: Time which a vehicle inside intersection can pass safely.
Type of Intersection1- At-Grade Intersection Three Leg:
Four Leg Intersection:
Multi- leg intersection:
2- Two level Crossing or InterchangeWhile two main road cross each other with high volume TrafficThen at grade intersection changes to interchange
References:• Highway Capacity Manual, Transportation Research Board,
Washington, D.C.2010.• A Policy on Geometric Design of Highways and Streets,
AASHTO, 2011.• Florida Intersection Design Guide 2015
THE ENDTHANKS FROM ATTENTION