Design & Construction Specifications - Town of Kernersville

A. Intersection Sight DistanceIn order for vehicles to safely maneuver into or through an intersection,sufficient sight distance must be provided so as to avoid collisions. Intersectionsight distance is measured from a driver's eye 3.5 feet high to an object 4.25feet high as measured from the pavement surface.The amount of sight distance required at an intersection depends on the type oftraffic control at the intersection and the speeds of the vehicles.1. Stop Sign ControlAt approaches to intersections that are controlled by stop signs or atdriveways where the driver is required to stop before entering the street,the driver must have an unobstructed view of the entire intersection andadequate sight distance for any of the various vehicular movementsallowed upon departure of the intersection. These movements mayinclude crossing the street, turning left or turning right onto the street.An obstruction to the driver's view shall not be located within the sighttriangles as defined herein to permit adequate view of the intersection.In addition, there shall be no sight obstructions located in the triangularareas shown in Figures 1 through 4 to allow for safe departure throughthe intersection. The measurement of intersection sight distance isalong the centerline of the appropriate lane of the roadway and ismeasured from an eye height of 3.5 feet above the surface of theroadway to an object 4.25 feet above the surface of the roadway. Thelocation of the driver's eye (d1) is dependent on the classification of theintersecting streets. For all intersections where the through street is athoroughfare, the driver's eye location shall be 15 feet back from theface of curb extended through the intersection, or the edge of pavementif there is no curb. At all intersections where the through street is a localor collector street, and for driveways, the driver's eye shall be locatedten (10 feet behind the face of curb extended, or the edge of pavement ifthere is no curb. The sight distance lengths d2 and d3 shown in Figures1 through 3 for left or right turns onto the through street are dependenton the design speed of the roadway and are presented in Table 3-1.Figure 4 shows the measurement method for determining the sight linefor left turns from the through street. Table 3-2 gives the minimum sightdistance for this movement across one, two, or three lanes (d1).