Abstract:
In Sri Lanka, rural roads are not explicitly designed on technical requirements.
So far restoration of rural roads went through with mere Construction enhancements
and appropriate geometric improvements have not been adopted. Itwas discovered
that the actual operating speeds can be higher after restoration which is affecting
the safety of road users. Aim of this research is to survey operating speeds, posted
speed limits and to find design operating speeds that expected to be after the rehabilitation.
The majority of the rural roads in Sri Lanka does not have posted speed
limits indicated by the geometric, road environment and functionality level of the
road. Consequently, the speed decision of the rural road drivers relies upon variety
of different factors. The 85th percentile speed was taken as the operating speed. This
speed was utilized as a basic for recommending rational speed limit. Selected roads
were divided into a few segments; straight and curved. Operating speed on straight
segments were given priority in suggesting rational speed limits. As operating speed
in curves are considerably lower and enforcing lower posted speeds only based on
operating speeds on curves for entire road and would not be practical. The recommended
speed limit for all the roads under purview is 50 km/h and this speed limit
will be superseded to a lesser speed limit at a curved segment, dependent on the
operating and design speed. This speed limit should be notified using sign boards
and shall be enforced only for the curve itself.
