Speed breakers are one of several tools to reduce traffic speed. Speed breakers are not appropriate for all locations and when used, they must be built as per IRC Guidelines which specifies the height, width, etc of the speed breaker as well as markings and signages required to warn motorists in time. Very few speed breakers in Chennai meet the criteria, making them ineffective as a road safety tool, says Sumana Narayanan, senior researcher, CAG.