Abstract: A roadway drainage installation comprising a roadway, an elevated pavement extending alongside the roadway, and a more or less horizontal apron extending alongside the roadway so that it is located between the roadway and the pavement at the level of the roadway. A curb extends upwardly from the apron to the pavement so that the apron and curb define between them a water pathway. A storm water conduit runs below the pavement, the apron and the roadway. A curb inlet device comprises an opening in the apron as well as an opening in the curb, with the openings being in communication with each other. The curb inlet device is connected to the storm water conduit such that water can pass from the water pathway, through the openings into the storm water conduit. Water-deflecting members are located in the apron opening.