A report sponsored by the American Association of State Highway and Transportation Officials (AASHTO) provides information and guidance on the use of porous, pervious and permeable pavers in roadway shoulders. The study supports recent federal infrastructure legislation (MAP-21) that encourages adoption of infiltration surfacing systems that minimize the environmental impacts of stormwater runoff.

A study commissioned by the American Association of State Highway and Transportation Officials (AASHTO) examines the functionality of permeable paver installations for roadway shoulder applications.

According to the study, state Departments of Transportation (DOTs) and other municipal organizations have expressed interest in permeable shoulders to assist in the overall management of stormwater.

The design would divert water from the surface of the roadway into a permeable shoulder above a stone reservoir, temporarily storing and treating runoff before it filters into the roadway subgrade soils or other stormwater conveyance and treatment systems.

The report assesses the ability of porous shoulders to reduce downstream infrastructure requirements (either conveyance and/or water quality treatment); various subgrade conditions likely to be encountered; recommended construction materials; changes to the surface drainage system; safety and maintenance issues; potential adverse impacts to the mainline structural section and other possible impacts of water infiltration into the shoulders.

The full text of the study is available here.