Effectiveness of an improved road safety policy in Ethiopia: An interrupted time series study

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Effectiveness of an improved road safety policy in Ethiopia: An interrupted
time series study
Article in BMC Public Health · May 2014
DOI: 10.1186/1471-2458-14-539 · Source: PubMed
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Teferi Abegaz
Hawassa University
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Yemane Berhane
Addis Continental Institute of Public Health
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R E S E A R C H A R T I C L E Open Access
Effectiveness of an improved road safety policy in
Ethiopia: an interrupted time series study
Teferi Abegaz 1*
, Yemane Berhane 2 , Alemayehu Worku 3 and Abebe Assrat 4
Abstract
Background: In recent years, there has been an increasing interest in implementing road safety policy by different
low income countries. However; the evidence is scarce on its success in the reduction of crashes, injuries and
deaths. This study was conducted to assess whether road crashes, injuries and fatalities was reduced following the
road safety regulation introduced as of September 2007 by Oromia Regional State Transport Bureau.
Methods: Routine road traffic accident data for the year 2002-2011were collected from sixteen traffic police offices.
Data on average daily vehicle flow was obtained from the Ethiopian Road Authority. Interrupted time series design
using segmented linear regression model was applied to estimate the effect of an improved road safety policy.
Results: A total of 4,053 crashes occurred on Addis Ababa - Adama/Hawassa main road. Of these crashes, almost
half 46.4% (1,880) were property damage, 29.4% (1,193) were fatal and 24.2% (980) injury crashes, resulting 1,392
fatalities and 1,749 injuries. There were statistically significant reductions in non-injury crashes and deaths. Non-injury
crash was reduced by 19% and fatality by 12.4% in the first year of implementing the revised transport safety
regulation.
Conclusion: Although revised road safety policy helped in reducing motor vehicle crashes and associated
fatalities, the overall incidence rate is still very high. Further action is required to avoid unnecessary loss of lives.
Keywords: Road crash, Road injury, Road death, Road safety law effectiveness
Background
Road traffic crash is a growing public health threat,
being responsible for 1.2 million deaths and up to 50
million nonfatal injuries globally. It is a big challenge
especially for low and middle income countries, 90% of
the victims were found [1]. Accident trends observed
in industrialized countries witnessed the rapid reduc-
tion over the last three to four decades, while a terrify-
ing increment reported from a number of developing
countries including Ethiopia [2,3]. The problem may
grow further in the coming decades; due to the rapid
rising of vehicle ownership associated with their eco-
nomic growth [4].
Evidence from high income countries showed that im-
plementation of appropriately designed and well enforced
road safety policy contribute a lion share for their impres-
sive achievements of the declining trend in the number
and severity of crashes [5]. According to the European
Transport Safety Council estimation, if all existing road
safety laws in European Union are enforced up to 50% of
death and injuries could be averted [6].
Likewise in recent years, many low income countries
are implementing improved road safety policy to deter
risky driving practices including: − exceeding the speed
limit, impaired driving by alcohol and drugs, phoning
and texting while driving, and not using seat belt [5,7].
However there is little empirical evidence as to their
effectiveness in reducing crashes, injuries and fatalities
[7]. For example, Brazil, after implementing an improved
traffic code with stiff penalty and media coverage a 21%
and 25% reduction of injuries and fatalities, respectively,
was observed [8]. A study conducted in Uganda follow-
ing, police enforcement using patrol cars equipped with
radar brings a 17% reduction of fatalities [9]. In Rwanda
a 30% reduction in traffic death was observed following
an improved legislative change complimented with pub-
lic awareness campaign [10].
* Correspondence: [e-mail]
1
School of Public and Environmental Health, College of Medicine and Health
Sciences, Hawassa University, Hawassa, Ethiopia
Full list of author information is available at the end of the article
© 2014 Abegaz et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain
Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article,
unless otherwise stated.
Abegaz et al. BMC Public Health 2014, 14:539
http://www.biomedcentral.com/1471-2458/14/539

This study was conducted to measure the level of
effectiveness of an improved road safety policy (Oromia
Regional State Road Transport Regulation No; 96/2007)
enforced as of September 2007. The Oromia Regional
state is one of the largest states in Ethiopia. This
improved road safety policy include the new road safety
laws (prohibition of cell phone conversation while behind
the wheel, driving without using a seat belt and not using
motorcycle helmet) and the amendment of the existing
road safety laws (excessive speeding, impaired driving
with alcohol and Khat and unsafe loading) by introducing
higher penalty rate including suspension of the drivers’
licens. Seat balt wearing, healmet use and phoning while
driving were enforced by using a roadside random check
up on a regular bases; however speed and alcohol were
not well enforced due to lack of radar and breath analyzer.
Methods
Study design
Interrupted time series design was utilized to evaluate
the effectiveness of an improved road safety policy
implemented by Oromia Regional State Transport Bureau.
Interrupted time series design is an alternative approach
used to evaluate the effects of any intervention, when
randomized control trials are infeasible or identification
of a control group impractical [11]. This design was
utilized by various researchers to assess the effectiveness
of health care intervention [11,12].
Study setting
The study was conducted on one of the main and busi-
est roads of Ethiopia, which extends south from the
capital Addis Ababa to Adama/Hawassa. This two-way
and two-lane road has an average width of 8 meters
and covers a total distance of 264 Km. It is part of the
main route of the country’s import and export corridor
from the port of Djibouti and part of the Trans-African
Highway (an international road that stretched from Cairo
to Cape Town). Moreover, the road has a significant
economic importance since many of the cash crops,
floriculture farms, recreational areas and tourist centers
are located across the stretches of the road. According
to the Ethiopian Road Authority report more than 20,
000 vehicles used the road daily.
Data sources
We reviewed traffic crash records, routinely collected by
the police officers from 16 district traffic offices for the
period 2002 through 2011. Additional data on daily vehicle
flow was obtained from the Ethiopian Road Authority.
Only crashes happened on Addis Ababa- Adama/Hawassa
highway was considered for this study. A data retrieving
form was developed and used to record information from
the crash registration (CR) book. A total of 16 traffic
officers, who are assigned as an expert in documentation
and reporting of crash related cases were recruited from
each of the 16 traffic offices and provide training. Further-
more, two senior police officers and the principal investi-
gator were involved in the data collection process as a
supervisor. Relevant information on the type and severity
of the crash, type of vehicles and road users involved in the
crash and the time and place of the crash was retrieved.
Data management and quality assurance
Those crashes lacked some of the relevant information
needed were excluded. Among the total 46 cases that
excluded from the analysis, 27 of them were reported
before the intervention and 19 of them reported after
the intervention. The main reason for the exclusion is
due to lack of information on injury severity and num-
ber of victims involved. The collected data was double
entered by two different data clerk, using the EpiData
3.1 statistical software. Once the data entry completed,
we run the frequency and print out the output of the
two datasets. Consistency was checked by comparing the
frequency and the difference was corrected accordingly
by using the original data retrieving form.
Statistical analysis
The revised road safety policy include the new road
safety laws (banning of cell phone conversation, unbelted
driving and not using motorcycle helmet) and the amend-
ment of the existing road safety laws (excessive speeding,
impaired driving with alcohol and Khat and unsafe
loading) which was implemented as of September 2007.
Prior to September 2007, road safety enforcement in
Oromia Regional State implemented by police officer
using less strict enforcement with low penalty. On the
other hand, the existing and the newly enacted road
safety laws were implemented in a coordinated way
(traffic police and transport expert) using a stricter law
enforcement to the extent of drivers’ licence suspension.
Seat belt wearing, helmet use and unsafe loading were
enforced by using a roadside random check up on a
regular basis; however, lack of road safety instruments
like; radar and breath analyzer hinder the implementa-
tion of speeding and alcohol intoxication.
In this study three different dependent variables were
considered in the statistical analysis: monthly rates of
non-injury crashes, fatalities and injuries per 10,000
vehicles. The explanatory variables were intervention
dummy variable coded 0 before the intervention and
coded 1 after the intervention. A time trend was used
to control the confounding effect of the underlying
trend on the actual intervention coded as 1 at the starting
month of the first observation and continued to the last
observation. To estimate the trend change we introduced
a scaled interaction term (the number of months counted
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