Photo 3: Road alignment.
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This involves measuring cross-section
elements such as road cross slope, widths
of carriageway and shoulders, identifying
road surface types and also checking
drainage channels;
Roadside objects which may impact the
severity of injury to the vehicle’s occupants
when errant vehicles collide with them
should be identified together with the
placement of rigid objects including the
installed barrier system;
Road furniture, which influences the
effectiveness of providing information,
guidance and warnings to road users
should be checked including the quality of
road signs, road markings and delineators;
Road surface conditions influence the
deceleration rate of vehicles, therefore
influencing,
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the braking distance,
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the effectiveness of the dissipation
of surface water that may cause
hydroplaning, and
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the comfort and stability of vehicles.
Checks should be made on the skid resistance
properties, texture depth, pavement surface
defects such as potholes and undulation of
pavement surface.
The on-scene investigation may need
to identify most, if not all, of these road
characteristics, subject to the type of road
accident under investigation. The findings from the
road environment assessments may or may not
be conclusive evidence as to what had happened
or what might have caused the accident. Hence,
further scrutiny of the findings may be necessary
to determine their relationship with other evidence.
Examining Physical Evidence on Site
When checking existing road environment and
conditions, the investigator should also be able to
visually scan through the area where the accident
occurred and identify any evidence to the cause of
the accident. It is important that the investigator
knows what evidence to look for and be able to
recognise and interpret the evidence.
For physical evidence, the inspection of the
road surface is vitally important. Skid marks,
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