The design vehicle is a choice to be made by the designer and its dimensions and operational characteristics of interest are its physical dimensions and turning characteristics.

Design Vehicle(s)

The design vehicle is also a choice to be made by the designer. In most instances, the design vehicle dimensions and operational characteristics of interest are its physical dimensions and turning characteristics. These influence the intersection geometry (corner radii, channelizing roadways, and islands). Larger and longer vehicles such as semi-trailers produce greater turning paths and require more space.

Selection of an appropriate design vehicle is highly context sensitive. Where the surrounding land use or that served by the road is industrial in nature, it is generally prudent to select a larger vehicle as the design vehicle. For residential streets or neighborhoods, delivery trucks or school buses may be more appropriate.

In the urban context, selection of a design vehicle should consider the needs of pedestrians and activities outside the traveled way. Longer vehicles requiring greater turning radii produce longer intersections, which increase crossing distances for pedestrians and may promote higher turning speeds.