GEOMATERIC DESIGN Sight Distance And Road Alignment
Traffic System • Components: 1. Vehicular Traffic --Cars, Buses, Trucks, Taxis – 2. Road Conditions-- Motorway, Highway, Urban Arterial, Rural roads 3. Driver Characteristics --Young, Drunk, Experienced, Learner’s License 4. Environmental Conditions-- Sunny, Foggy, Night-time conditions 5. Control Devices-- Signs ,Signal ,Traffic Marking
Sight distance • Sight Distance. • Distance a driver can see ahead at any specific time • Must allow sufficient distance for a driver to perceive/react and stop, when necessary • Different types of sight distances, • • • • Stopping Decision Passing Intersection
Sight distance……(ctd.) • Road geometry affects the sight distance available to the driver. • Sight distance, in the context of road design, is defined as "the length of roadway ahead visible to the driver.” • " Sight distance is how far a road user (usually a vehicle driver) can see before the line of sight is blocked by a hill crest, or an obstacle on the inside of a horizontal curve or intersection. • Insufficient sight distance can adversely affect the safety or operations of a roadway or intersection.