Assessing Major Safety Issues on Highway-Railroad Grade Crossings along the Addis Ababa Light Rail Transit
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Date
2016-08
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Of the whole railway line, the major part where frequent accidents occur is highwayrailroad
at
grade
crossings.
The
grade
crossings
along
Addis
Ababa
Light
Rail
Transit
(AA
LRT)
are
located
at
areas
with
high
pedestrian
and
vehicular
traffic.
Therefore
safety
levels
at
AALRT grade crossings will be major concern during operation. This research study
assessed major safety issue at highway-railroad at grade crossings along AA LRT using
accident rating models and highway-railroad level crossing engineering design guidelines
and standards.
The study identified the design and construction of highway-railroad level crossings along
AALRT satisfied most of the design guidelines and criteria outlined by American Railway
Engineering and Maintenance-Of-Way Association AREMA manual, Chinese standard
GB50090, Federal Highway Association FHWA handbook and manual on uniform traffic
control devices MUTCDS.
Despite being compliant to the above design standards, level crossings at Tsehay
Realestate roundabout, Salitemihiret roundabout, Adey Ababa and Sebategna junction
found to have highest accident number. The geometry of the crossings and the traffic
volume operating at these sections of AALRT are found to be major reasons for such high
accident rate.
For type āFā traffic control system the smallest expected accident number per year is 0.28
at Kality side Meshualekiya roundabout level crossing. This result is higher than 0.075 a
threshold value for the use of type āGā traffic control system. Therefore the gates at the
level crossings of AALRT should start operation.
When gates are operational, accident frequencies from US DOT model are greater than 0.2
on the above hazardous level crossings. This 0.2 accident/year is the threshold value for
grade separation. Therefore level crossings at Tsehay Realestate roundabout, Salitemihiret
roundabout, Adey Ababa and Sebategna junction should be considered for grade
separation if the cost of grade separation can be economically justified based on fully
allocated life-cycle costs.
Description
Keywords
Highway-railroad grade crossing safety, Light rail transit system, design standards, accident rating models