Motorcyclists are vulnerable to skidding on metal covers which typically have a lower skid resistance than the surrounding pavement. Where there is a sudden change in road surface properties, it can lead to stability issues for motorcyclists.

The locations that are most problematic are where a cover is located within the riding line in areas where a motorcyclist is likely to brake, turn, accelerate and/or change lanes. This can be a particular issue on curves, intersections, and roundabouts.

Treatment

: Historically, metal covers for utilities and storm drainage have been located within the pavement. However, designers should strive to ensure that metal covers are not designed for new pavements, including main lanes, shoulders, turn lanes, and median openings of high speed and/or arterial roadways. If these facilities already exist in the pavement, they should be relocated where practicable.

Where there are existing metal covers that cannot be practically moved, then they should be treated with a surface or coating so that the polished skid resistance value (PSRV) matches the surrounding pavement.

Details for metal coverings should also be reviewed to ensure that the tops are flush with the adjacent pavement and do not present a height differential.