Where medians do not exist or cannot be provided, designers should strive to mitigate potential adverse effects. Left-turn restrictions and the institution of access control can reduce rear-end/left-turn conflicts.

Where medians do not exist or cannot be provided, designers should strive to mitigate potential adverse effects. Left-turn restrictions and the institution of access control can reduce rear-end/left-turn conflicts.

Where narrow median widths exist in urban areas, designers can consider the re-allocation of cross section width. The provision of a minimally functional median dimension (i.e., to enable placement of raised barrier, provide left-turn storage, or shield pedestrians) can be accomplished through marginal narrowing of lanes, elimination of on-street parking, and re-striping lanes. The Roadside Design Guide (3) provides guidance on the use of barriers for narrow medians.

Turn-arounds and/or jughandles can be used to provide access where it is desired or in place of a center left-turn lane where sufficient width for a median does not exist.

From A Guide for Achieving Flexibility in Highway Design, 2004, by the American Association of State Highway and Transportation Officials, Washington, D.C. Used by permission. AASHTO publications may be purchased from that organization's bookstore at 1-800-231-3475 or online at http://bookstore.transportation.org.

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