Traffic Report

INTERSECTION SIGHT DISTANCE The intersections of Bongart Drive and Oval Road and Warner Road and Davey Drive have been identified as having questionably inadequate intersection sight distance from the minor stop controlled approaches. Specifically the sight distances from Bongart Drive to the north and south and the sight distances from Davey Drive to the east and west are in question. Both Bongart Drive and Davey Drive form the stems of their respective tee intersections. The standards for intersection sight distance are found in “A Policy on Geometric Design of Highways and Streets” published by The American Association of State Highway and Transportation Officials (AASHTO). This design manual is referred to as the “AASHTO Green Book or AASHTO Manual” and contains most of the standards for highway and roadway design. The Manual states that sight distance from an intersection approach is measured from a point 14.5 feet back from the edge of travel way of the intersecting street and 3’6” above the pavement to a point in the middle of the intersecting street’s approach lane, also 3’6” above the pavement. The driver’s eye is conservatively assumed to be 3’6” above the pavement which is lower than the driver’s eye in most vehicles. The required sight distance, measured along the major intersecting street, is a function of the speed of vehicles on the major street. The speed of vehicles on Warner Road in the vicinity of Davey Drive is conservatively assumed to be 25 miles per hour. It is probably lower due to speed bumps on Warner Road. The speed of vehicles on Oval Road in the vicinity of Bongart Drive is assumed to be 30 miles per hour. The AASHTO manual states that the required intersection sight distance for a stop controlled approach to a street with a travel speed of 25 miles per hour is 280 feet and to a street with a travel speed of 30 miles per hour is 335 feet. Therefore, the required sight distance from Davey Drive at its intersection with Warner Road is 280 feet; and the required distance from Bongart Drive at its intersection with Oval Road is 335 feet. 29