Winter maintenance considerations in transportation planning Pat Kennedy, P.E. Engineering Supervisor, Denver Street Maintenance Denver, Colorado Member, APWA Winter Maintenance Subcommittee
hether constructing new or expanding existing roads, the planning for a major project brings together many disciplines, each having a different frame of reference and focus. Transportation is more than just cars; there is mass transit, light rail, bicycles, and pedestrians moving around in the same corridors. Pavement design, lane configurations, streetscape elements, vegetation, storm drainage, and public art are all part of the planning process. Rarely, however, does winter maintenance become part of the planning effort, but minor design details can have major consequences when winter arrives. Roundabouts assist in slowing traffic while increasing safety and mobility of the public. These items can also be a hazard when snow has decreased visibility or partially covered them. Plow drivers are maneuvering heavy pieces of equipment during marginal weather when visibility is low. A plow impacting a curb can damage both the equipment and the curb line. Sloped curbs instead of vertical curbs along the central or channelling medians can create the visual barrier needed for traffic but a plow blade will ride up over the curb minimizing the damage and injury potential. The turning radius of plow equipment must be considered when setting the curves and locations of curbs associated with these structures so they may be properly cleared of snow. Roundabouts also create unique problems with snow 88 APWA Reporter
July 2012
storage. The entrances and exits, as well as pedestrian facilities, use up much of the available perimeter space that could be used for snow storage. Placing snow in the central island will create icing problems if the pavement slopes away from the center. Melt will flow across the pavement and refreeze at night creating hazardous conditions. Traffic calming devices such as intersection bulb outs and center refuge islands provide a safer pedestrian environment, but they are also obstructions to plowing operations requiring skilled maneuvering by the plow driver. Bulb outs also create pockets that are difficult to clear and can become
collection points for debris and snowmelt if not properly constructed with drainage structures. Many cities are undergoing a change in the way that lanes are laid out. Parking is being removed and bike lanes are taking their place. What may have previously been used as storage for plowed snow now must be cleared for the bicyclists that are using the streets for commuting. Additional passes by the plow will be necessary and, in some extreme cases, expensive and time-consuming snow hauling will be needed. Pavement in a shaded area will be 10°F or more cooler than pavement exposed to the sun. Snow that falls
Geometry can make roundabouts difficult to plow.
