Roadwork zones induce problems to the traffic flow,
decreasing the level of safety. A number of factors come into play including:
the type of work, type of road, volume, composition and speed of traffic flow,
road alignment, weather conditions and visibility.
Roadwork sites increase accident rates and the severity of
Reducing this problem requires an integrated and systematic
approach aimed at identifying and solving the safety problems of the work
zone. An effective approach, which is quickly spreading at the international
level, is the work-zone safety audit in both urban and rural areas. The audit
is a formal examination of a future road or traffic project, an existing road
or any project that interacts with road users. An independent, qualified team
reports on the project’s potential accident and safety performance.
In countries such as Italy, where there are no work-zone
standards or guidelines related to traffic management and safety aspects, such
a procedure may be beneficial in providing a general safety improvement.
The audit team applies the principles of road safety
according to a multidisciplinary perspective, taking into account the needs of
all road users: car drivers, pedestrians, cyclists, motorcyclists, children,
elderly people, people with disabilities, truck and bus drivers and public
The objectives of a safety audit at work zones are:
identify potential safety problems for road users and others; and
ensure that measures to eliminate or reduce the identified problems are fully
considered by the client and those involved in construction, maintenance or any
other road activity which may affect normal operating condition of the road.
Just their opinions
The road safety audit is aimed at identifying and solving
risk factors by trying to investigate how the road environment is perceived and
ultimately utilized by different road users. Part of the analysis involves a
comparison process between the opinions expressed by a team of safety
specialists. The audit procedure includes the involvement of the following
The client commissions audits at proper project stages,
selects an audit team with the appropriate training and experience, reviews the
formal audit report and acts upon recommendations whenever appropriate and
The designer is responsible for the traffic management
scheme and provides the audit team with all the background information to the
scheme. This person also responds to initial audit findings.
The team should be made up of more than one person and
should have adequate experience in road safety engineering and practices,
accident in- vestigation and prevention, traffic engineering and road design.
The work-zone work flow
Work zones are dynamic environments. Therefore, it is vital
for the audit process to be a quick mechanism to identify and correct unsafe
The main steps of the safety audit are:
selects the audit team;
provides necessary documents to audit team;
preliminary meeting be-tween all subjects involved is carried out and audit
objectives and procedures are set;
team examines all project documentation and drawings;
team conducts site in-spections, both in daytime and nighttime and both as
motorists and pedestrians;
team then reviews the results of the site inspections and documentation
analysis. Checklists, photographs and videos are a useful prompt for the
auditors. The team singles out potential accident scenarios by prediction of
accident types and their contributing factors, and defines possible
team writes the safety audit report, in “problem/recommendation”
format, where the problem is described in terms of an accident risk to a road
user and the recommendation is an engineering solution to the reported problem.
Recommendations produced by the audit team should indicate the type of measures
without specifying detailed technical issues;
completion meeting between all subjects involved is held and the proposed
recommendations are examined and discussed;
designer reviews the audit report and communicates to the client any and all
client examines the audit report and the designer’s observations and
decides about the implementations of the recommendations; and
client responds to the audit report by writing an exception report.
Safety audits also should be done at the end of work-zone
installation, during work through repeated, unannounced site inspections and
after work-zone removal to verify if the risk factors caused by the work zone
The audit team only examines aspects influencing user
safety, but it doesn’t consider other elements, which can refer to other
judgment criteria unrelated to safety. Therefore, the team should analyze, for
example, if users correctly perceive the work zone not only during the day but
at night and in bad weather conditions as well. If there is a high pedestrian
flow, the analyst should simulate all the scenarios in which different types of
pedestrians (i.e., an elder with walking difficulties or a child) who could be
covered by signals or work-zone equipment.
What made the list
Checklists are used so the audit team does not overlook important safety problems. Checklists are not a substitute for knowledge and experience, and should only be used as an aid. A checklist specifically suited for work zones is split into five sections.
Traffic management style='font-size:10.0pt'>
Work zones may induce rerouting of road users in the
network. Characteristics of the road network affected by the work zone have to
be analyzed, taking into special consideration vulnerable road users.
Work-zone layout style='font-size:10.0pt'>
Work zones consist of five areas: advance warning,
transition (usually one of the most critical issues for work-zone safety),
buffer (which provides a longitudinal and lateral recovery for motorists and
workers), traffic and termination.
Signs and lighting style='font-size:10.0pt'>
The road system must provide adequate visual information to
enable the driver to adapt his behavior to the work-zone conditions and also
enable the pedestrian to safely walk to the intended destination. Permanent and
temporary signs and markings must correctly interact with each other.
Roadside obstacles style='font-size:10.0pt'>
In work zones, many accidents involve the vehicle leaving
the road. Longitudinal safety barriers, their transitions and terminals should
provide adequate protection to roadside obstacles.
Work-zone operations style='font-size:10.0pt'>
Interaction between work activities and traffic flow may be an
accident-contributing factor, especially if the buffer area is insufficient.
A risk’s worth
A problem’s magnitude may be quantified by conducting
risk assessments. Various risk assessment procedures can be used.
The easiest approach involves the audit team prioritizing
the safety issues based on experience, but this method is somewhat subjective.
A more objective approach involves the prediction of the
frequency and severity of potential accidents associated with each problem
identified in the audit report. A risk assessment matrix, where the risk score
depends on both the frequency and severity of potential accidents, may be used.
The auditors would go through the report and give each
problem a risk score, making their assessments of risk if nothing is done.
Then, the auditors would go back through their recommendations and, making the
assumption that the recommendation will be carried out, reassess the risk. With
this procedure, the team not only looks at the existing road, or project,
deficiencies but also takes into account that those problems could produce road
accidents and that the suggested improvements may reduce the accident
Pilot work-zone safety audits have been performed both in
urban and rural areas. A team of two inspectors inspected each site
twice—day and night. The visits were not announced and work-zone drawings
were not available.
The safety audits identified many problems. Fixing those
problems required low-cost safety measures such as the insertion of longitudinal
and transverse buffers, better markings and signing, the adjustment of road
restraint systems and the construction of pedestrian facilities.
Two work zones in Naples, Italy, were inspected. In the
first site, the work zone occupied a three-way intersection and was located on
a sharp bend. In the second area, the work zone took up one of the two lanes,
with alternate one-way traffic managed by signals.
Many traffic management problems were encountered, most
involving the formation of queues. In the first work zone, there was a problem
with a queue at traffic lights. Vehicles arriving at the lights could not see
the queues because of the presence of a bend. Furthermore, in the bend there is
a work-zone sign (“We are working for you”) in the center lane that
compels the users to divert to the outer lane, causing the potential for
head-on accidents. Similar problems were encountered in the second work zone,
where work-zone warning signs were absent. Both sites also lacked a safe route
for pedestrian traffic.
The work-zone layout is usually the most relevant safety
aspect. Here, the work zones scored failing grades because there was a lack of
both longitudinal and transverse buffer areas and the configuration of the
traffic areas was wrong.
Signage and lighting was another trouble spot. In most cases
there was a lack of warning signs and markings, and the existing signs and
markings carried the wrong color and didn’t provide adequate information
to the user. Sign maintenance also was poor and there was a lack of delineation
along the path of the work zone.
The roadside obstacle safety level was equal to an
‘F’ because the zones lacked safety barriers, and in several cases
open excavation was not blocked by any kind of protection device or restraint
A common problem in work-zone operations was the work was
carried out very close to the traffic flow. Accesses to the work place also
were positioned in dangerous areas.
A third work zone was a two-lane rural highway located in
Pozzuoli, Naples. It consisted of the roadside and part of one of two lanes and
caused the narrowing of both lanes. A fourth work zone was on the A3
Naples-Salerno motorway and included a succession of work zones.
Problems in the rural zones were similar to the ones found
in the urban environment. The main difference was a faster travel speed, which
increases both the number and severity of accidents.
On the motorway there were many problems related to the
limited road capacity. Congestion problems caused many users to use adjacent
roads with lower geometrical and functional characteristics. As a result, road
accidents could have increased.
Buffer areas were generally absent in the rural areas, too.
There was a lack of work-zone alert signs, incorrect horizontal markings and
signs out of position. On the motorway, signs were often positioned in the
wrong way. There also was a coexistence of permanent and temporary markings,
which could have led to driver confusion.
Roadside obstacle problems were common to both the urban and
rural areas. In the motorway a common problem was the absence of separation
between traffic moving in the opposite direction.