Abstract:
In densely urbanized area s with intensive land uses, traffic calming is a vital safety
countermeasure to avoid violation of permitted speed -limits in hazardous areas such as;
approaches of un-signalized at-grade intersections and upstream of surface pedestrian -
crossings at or nearby densely land-uses such as; schools, hospitals, worship houses, etc.
Previous researches showed that speed calming is usually done by either horizontal or
vertical deflections in road alignments. Horizontal deflections in road alignment could be
achieved through narrowing carriageway width, adopting horizontal alignment to prevent
over speed, etc. while vertical deflections in road alignment could be achieved through
instillation of speed humps upstream to the required speed calming or temporary work -zones
locations. This paper focuses on determining actual traffic performance up - and downstreams
of speed calming countermeasures using vertical deflections in road alignment
(humps and speed tables) to study the influence of their physical and geometric
characteristics on traffic performance, in terms of speed profile and also to extract some
guidelines for their most suitable locations.