INGENIEUR
Photo 2: Taking notes on eyewitness account of an accident.
they must be carefully scrutinised. Distance,
lapsed time, and speed are the key elements
of most vehicular accident evaluations but
they are difficult to judge accurately even by
an experienced observer. Furthermore, drivers
involved in the accident are notorious for under-
estimating their own speed and over-estimating
the speed of the other driver.
Assessment of Road Features and Conditions
The design and construction of roads should
incorporate all the elements of road safety.
However, this may not necessarily be the case.
Compromises sometimes have to be made due
to financial limitations and technical requirements
such as traffic capacity, traffic safety and others.
Safety deficiencies ‘built’ into a road may
have caused or contributed to some extent to
the cause of the accident. Hence, in an accident
investigation, there are many aspects of road
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2018
VOL 76
55 OCTOBER-DECEMBER
JUNE 2013
characteristics that need to be checked and
assessed, as follows 8 :
● ●
Road layout may influence the driver’s
perception of the level of safety and his
driving behaviour and may also influence
the driver’s choice of speed and reaction
time. The elements of design that should
be checked are sight distances, horizontal
curves and super elevation of curves
and the placement and configuration of
junctions or intersections;
● ●
The road profile which may influence a
driver’s sight distance, and therefore his
ability to realise the hazard in time, should
be checked including vertical alignment
and sight distances;
● ●
The road cross-section, which influences
the lateral forces that act on the vehicle on
different occasions and provides or denies
easy manoeuvrability should be checked.