Turn Characteristics

Design Vehicle - Turning Characteristics

Turning Characteristics

When designing an intersection, the largest design vehicle specified for that intersection should be able to negotiate the turn without climbing adjacent curbing and channelization islands. WB-67 is the most common semi-trailer. Commercial locations such as the BX, commissary, gas stations, or any other location that moves large quantity of goods should accommodate this truck. This would also include major roadways used to access these facilities.

Minimum Turning Radius

Design Vehicle Passenger Car City Transit Bus Intermediate
Interstate Semitrailer
AASHTO Symbol P City Bus WB-40 WB-62
Minimum Inside Radius (Ft.) 23.8 41.6 39.9 44.8
Minimum Design Turning Radius (Ft.) 14.4 24.5 19.3 7.4

The chart above shows the minimum turning radius of four design vehicles: passenger cars, buses, intermediate semitrailers and interstate semitrailers. When designing intersections and other facilities that require tight movements by vehicles, these values must be considered for the appropriate design vehicle.

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