Abstract:
Though 119 accidents had occurred on Colombo- Katunayake Expressway with a rate of
12 accidents per month and only one death occurred during the period of ten months. 16
people had died on Southern Expressway within the period of thirty three months with a
total of 1,190 accidents and a rate of 36 accidents per month, raising concerns about the
safety of travelling on Southern Expressway. The objective of this study was to conduct
an analysis to estimate the degree to which road accidents were due to adverse weather
conditions.The study was confined to the segment between Kottawa and Pinnaduwa
exits. The secondary data collection was done on two aspects. The accident analysis
was based on unpublished data for the period between January 2012 and May 2014. The
data on weather conditions were obtained from the Department of Meteorology.
Published thematic maps for both aspects were taken into the analysis. The average
annual rainfall in the area is higher than other parts of the country, an indication about
the intensity of raining. The monthly rainfall figures indicate the peak rainfall period is
associated with South-West monsoon and second inter monsoon, an indication for the
necessity of extra precauations. The average annual number of rainy days is 150 or
above, indicating over 40% of the days in a year is expected to be rainy days. Three
aspects of accidents were identified: road surface condition, speed of the vehicles and
type of the vehicles. The accidents data indicate about 85% of accidents were involved
with wet and slippery road conditions. Over 60% of the accidents occurred when the
vehicle speed was between 80 to 100 km per hour and cars were involved in over 70%
of the accidents. The study reveals that adverse weather leads to some accidents directly
or indirectly. Increasing trends in extreme rainfall events may also accelerate adverse
weather related accidents. Future studies should investigate the behavior of road in
relation to weather and its interaction with different weather conditions. The authorities
should collect information on accidents to compare the data with rainfall patterns for the
identificatiorj of links between them.
