A median is a desirable element on all streets or roads with four or more lanes. The principal
functions of a median are to prevent interference of opposing traffic, to provide a recovery
area for out-of-control vehicles, to provide areas for emergency stopping and left turn
lanes, to minimize headlight glare, and to provide width for future lanes. A median should
be highly visible both day and night and in definite contrast to the roadway.
Width. The width of a median is the distance between the inside edges of the pavement.
See Fig. 2.27 for examples of various medians. The width depends upon the
type of facility, topography, and available right-of-way. In rural areas with flat or
rolling terrain, the desirable median width for freeways is 60 to 84 ft (18 to 26 m).
Although the minimum median width is normally 40 ft (12 m), narrower medians
may be used in rugged terrain. A constant-width median is not necessary, and in fact,