A number of rumble installations have been constructed on rural roads in South Africa and although no local accident data are available the provincial roads engineers consider them of value in alerting drives to the need for caution on the approaches to hazardous curves or intersections. City and town engineers had little to report on rumble installations but showed a keen interest in their potential usefulness. Each type of rumble device has certain merits and these are discussed in this report. It is recommended that the intermittent rumble surfaces be used in rural areas and the continuous rumble surface in urban areas. The length of the installation should be related to the speed reduction desired. Guidelines to the layout and construction of rumble installations are given in this report. It is concluded that rumble devices should be considered only as additional measures where existing warning signs and markings have proved to be ineffective on their own.
