Incident Management - An interactive ITS Handbook for Planning
Relevance for Large Scale Events
Best Cases and Examples
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An incident is an event which occurs without prior notice. It can degrade safety and/or slow traffic flow
and may include vehicle breakdowns, vehicular crashes, adverse weather conditions and debris on the
road. Unplanned incidents can result in severe injury and/or death and may require the partial or full
closure of the affected roadway.
Traffic incident management refers to the delivery of planning and operational tasks by the responsible
road authority in response to an unplanned incident. This is achieved through collaboration with
emergency services and other key stakeholders to facilitate effective management of road users, the road
network and infrastructure. Incident response plans (IRP) are developed in anticipation of a full unplanned
closure of a state road. The IRP defines the diversion route(s) and roles and responsibilities of the agencies
Fig. 1. Overview of incident response planning process.
The purpose of ITS tools in this context is to provide automated functionalities which can help to give a
faster and more efficient response and calculation of strategies which enable transportation agencies and
other agencies to manage road incidents more effectively.
These tools can contribute in various ways, including:
the detection of incidents: this can be achieved directly (using data coming from crash detection
sensors) or via the processing of traffic flow data (e.g. inductive loops, infrared sensors, floating car
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data) using appropriate algorithms, which permit the identification of probable incidents (these are
then verified e.g. by CCTV images or the police);
the diffusion of information: this permits indications on how to deal with the incident to be
communicated to road operators and recommendations sent to drivers (collectively, e.g. via VMS,
or individually, via mobile devices);
support in the definition of management strategies: i.e. identification of the optimum strategy for
redistributing traffic on the road network.
Implementationof priority strategies: e.g. priority given at intersections to emergency vehicles (e.g.
ambulances) in collaboration with UTC functions.
As regards the planning process, a key component is the consultation with stakeholders to attain
agreement on the incident response plan. Consideration is given to constraints on diversion routes such as
the type and condition of infrastructure (bridges) and suitability for heavy vehicle use. Consultation may
involve written correspondence and workshops through to the establishment of an Incident Management
Planning and Operations Team, which include the RTA, Police, and local council.
An “incident” is defined as any non-recurring event that causes a reduction of roadway capacity or an
abnormal increase in demand. Such events include traffic crashes, disabled vehicles, spilled cargo, highway
maintenance and reconstruction projects. Traffic incidents have a great effect on the safety of responders
and on the mobility of the travelling public using roadways. In 1999, over half of the police officers killed in
the line of duty died in traffic crashes. These secondary crashes are estimated to cause 18% of deaths on
freeways. Traveler mobility and productivity are also affected by incidents and incident management. Well
over half of non-recurring traffic delay in urban areas, and a large majority in rural areas, is a result of traffic
Fig. 2. Secondary crash generation by an incident on an highway.
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Integrated traffic incident management is emerging as a proven solution to address these safety and
mobility concerns. Traffic incident management is a planned and coordinated process to detect, respond
to, and remove traffic incidents and restore traffic capacity as quickly as possible. It involves the
coordinated interactions of multiple public agencies and private sector partners through the
implementation of ad-hoc ITS tools and platforms aimed at the supervision of a wide area and at the
diffusion of RT updated information to the drivers. ITS are particularly relevant to incident management.
Indeed, it is during atypical events, such as incidents and catastrophic weather, that ITS provides the
greatest benefit. In particular, ITS tools can be effectively used in different phases of the incident
Detection: The most common variants applied in incident detection can be grouped into three
- Citizen reports: e.g. mobile telephone calls from motorists, and via SOS call boxes. All
verified information needs to be integrated in the incident management platform;
- Reports from professionals: e.g. police patrols, aerial surveillance, public works crews,
traffic reporting services, service patrols etc can serve as incident reporting sources. Once
the call comes in to an operations or dispatch centre, it could be handled with higher
priority than other motorist calls. The main issue of this kind of reporting is how to get this
data into traffic supervision platforms (see below). An effective solution can be the
development of smart phone mobile apps for easy incident reporting, which are able to
connect to traffic management centre and exchange traffic and incident detection data into
a common format;
- Electronic techniques: CCTV, AVI, electronic traffic measuring. For further information, see
Traffic flow monitoring and Automatic Incident Detection systems): large traffic monitoring
systems (traditionally based on inductive loops or the analysis of CCTV images but also more
recently wireless sensor networks) can contribute to the real-time estimation of traffic flows in the
road network of a wide area. Comparing the flow pattern with historical ones, it is possible to
automatically detect sudden slowing of traffic or the formation of unexpected queues. This permits
the identification of a possible incident which is then verified by other means. can be used to
automatically highlight possible area where incidents have occurred.
Support in mobility strategy (e.g. rerouting): more advanced traffic supervision platforms integrate
specific traffic rerouting algorithms. Such platforms are software solutions which provides
algorithms and interfaces in applications, services, and client engines to use the data in order to
perform a coherent solutions to the main goal: manage traffic data, variable message sign and all
the subsystems installed in the UTC centre to perform the objectives to maintain the traffic in
equilibrium on the network and inform travellers about the traffic situation. Using these platforms,
the traffic operator can manage the mobility of the area of the incident, keeping into account the
actual status of the road network (in terms of flows, events, weather, congestion), even as
suggested by the platforms itself.
Information delivery: in this case ITS are used both in the coordination of the VMS systems and as
devices for information delivering. Coordination of VMs systems can be operated in two different:
- By advanced traffic supervision platforms, which integrate VMS control;
- By proprietary software for VMS control.
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The first solution grants an higher level of integration between information services and allows the traffic
operator to have a global view of the whole scenario of the incident.
(Emergency) vehicle priority: in most advanced in fully integrated wide-area supervision and traffic
light control platforms and in order the speed up the delivery of first aid actions, specific categories
of vehicles, e.g. emergency ones, can receive priority at traffic lights (see also “Technologies”
section for more detailed information about this functionality).
Relevance for Large Scale Events
In case of large events, the consequences of the incident will be even more serious, because of several
Presence of high peak flows;
Drivers not familiar with the road network;
Presence of special vehicles (e.g. VIP, government, …);
Tightness of times to clear the road (critical in large events).
Furthermore, during large events it is possible to find a sort of specific problems, not directly related with
traffic conditions, which can increase the consequences of an incident:
Terrorism: during large events, especially in critical areas, many people will be frightened of
terrorism and this may cause general lacking of protection feeling and subsequently panic in people
not properly informed about an incident.
Security alerts: due to the presence of a large amount of people (most of them with any knowledge
of the area of the event), all information should be carefully checked and validated before being
published in order not to generate counterproductive behavior in the attendees.
Weather conditions: sometimes large events (e.g. as regards Winter Olympics) are organized in
location with severe weather conditions. These can affect both the operation of ITS systems and
the number of incidents due to the bad conditions of the road surface. Monitoring and control
systems redundancy is therefore suggested.
For these reasons, the implementation of incident management tools can be considered as one of the most
important steps for the successful organization of a large event.
The incident management activities require the skills and expertise of a diverse disciplines and agencies. To
develop an effective incident management program or to improve an existing one, it is important to
understand the roles that various agencies play in incident management, especially as regards large scale
The most common variants regard the level of ITS platforms integration within the ITS incident
management process. There four many categories of incident management tools:
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Stand-alone system. In this model, the traffic operator simply receives incident information
through different channels (maybe also by road sensors systems), as already mentioned in the
“Description” section, manually identifies the incident and uses a dedicated application (or
internet-based service) to delivery information by different channels. The most common mean of
information divulgation is represented by VMS.
Fig. 3. A VMS used for drivers information. [From en.wikipedia.org]
VMS are very common on highways where traffic flow is critical for the safety of the travelers.
Furthermore, VMS are used to inform driver also regarding other kind of potentially dangerous traffic
events like road works or adverse weather conditions.
Monitoring platform. In this model, a part of the functionalities of the previous one, the platform is
able to connect with the traffic monitoring systems located in the area in interest. In this way, the
traffic operator has a global view of the area and therefore can activate reaction protocols on the
base of the actual status of the road network. This is particularly relevant for large scale events,
because it enables the operator to make decision taking into account atypical situations (slowing,
…) related to the happening of the event.
Strategic supervision platform. This kind of integration adds to monitoring integrated platforms
the capability to dynamically route vehicles, giving personalized and real-time updated traffic and
navigation information to the drivers. The most common method to spread this information is
based on mobile apps running un handheld devices or navigation systems able to receive traffic
information from the traffic management centre.
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Fig. 4. Architecture of a supervision platform. [By Courtesy of MizarAutomazioneS.p.A.]
This integration leads to the optimization of traffic flows over the whole network, which is kept into
equilibrium conditions and for this reason can be used at its best efficiency conditions.
Strategic and control integration. This kind of platforms is characterized by a direct link between
the supervision platform and the UTC system. In most advanced platforms also the parking
guidance system is integrated into the architecture of the platform.
Fig. 5. Architecture of a fully integrated platform. [By Courtesy of MizarAutomazioneS.p.A.]
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This represents the most advanced state-of-the-art solution and enables the traffic operator to take
decisions and activate protocols having knowledge and control of all the traffic monitoring and regulation
services of the area of the incident. For example, priorities action for emergency vehicles can be activated
(see also “Technologies” section).
Detection and surveillance technologies serve several traffic management functions, including traffic
monitoring and data collection. Typical data collected via these technologies include vehicle volumes,
speeds, occupancy, and traffic density. Surveillance technologies have some utility in detecting incidents. In
practice, surveillance technologies are most useful for incident verification.
Magnetic, or inductive loop detectors, which are embedded beneath the roadway pavement, are the most
common form of automated vehicle surveillance. In use for decades, they do have several limitations. They
are prone to failures, and servicing them, which requires opening up the pavement, can cause serious
disruption, particularly in high-traffic areas. These limitations have prompted the development of
alternative forms of traffic surveillance like magnetometer, infrared or microwave radar detection, or even
floating car data (FCD).
Fig. 5. Examples of magnetometer (left) and radar (right) for vehicle detection.
Video-Image Processing is another form of non-intrusive vehicle detection. It works by monitoring specific
points in the video image of a traffic scene to determine changes in successive frames. Typical video image
processing systems include one or more video cameras, a microprocessor system to process the video
images, and software that translates the processed images into vehicle detection data. A disadvantage of
video imaging is its sensitivity to light and shadows, which can cause the processing systems difficulty in
accurately interpreting the images. The performance of video imaging processing systems can be, however,
enhanced by improving their detection algorithms. Another disadvantage, compared to other detection
systems, is its very high cost. However, the advantages of video-imaging detection over other forms of
traffic surveillance are significant
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The life-cycle cost for video imaging detection is lower than embedded loop technologies in most
Installation is less expensive in terms of labor, materials, equipment, time, and disruption to the
Maintenance can be done year-round, with minimal traffic disruption;
Detector regions can be relocated or added with software;
Resurfacing or construction projects do not affect traffic detection;
Camera location is flexible, and can be controlled remotely;
Very little training is required for installation staff.
Automated incident detection algorithms are the mechanisms by which traffic surveillance methods are
translated into incident detection data. An algorithm is set of computational rules for the solution of a
mathematical problem within a finite number of steps. An algorithm allows a person or a computer to
determine relationships among various sets or pieces of data. For instance, various types of incident
detection algorithms have been established to allow computer systems in traffic operations centers to alert
operators to the possibility on an incident in any part of the traffic network for which traffic data are
available. The operator can then use other equipment, such as CCTV if the incident occurs within proximity
to the camera, to verify that an incident has occurred, and to assess its scope.
Fig. 6. ITS platform for visualization of network state and incident management
In order to detect an incident electronically, data regarding vehicle volumes, speeds, and/or occupancy
(whether a particular detection area is occupied) are taken in from the devices discussed previously,
compared, and analyzed against various scenarios. Incident detection algorithms can be divided into the
four major categories including:
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Comparative (or pattern recognition) algorithms compare traffic parameters at a single detector
station or between two detector stations against thresholds that define when incident conditions
Statistical algorithms use statistical techniques to determine whether observed detectors data
differ statistically from historical or defined conditions;
Time-Series/Smoothing algorithms compare short-term predictions of traffic conditions to
measured traffic conditions.
Modeling algorithms use standard traffic flow theory to model expected traffic conditions on the
basis of current traffic measurements.
Finally, priority tools, integrated with the local traffic light managing platform, can be used in order to help
the emergency vehicles to reach the place of the incident. Priority techniques are linked to adaptive
signaling strategies and in standard conditions are applied to public transport vehicles. On the other hand,
after receiving a report of an incident, the emergency management centre can send information of the
path that will be followed by emergency vehicles to the traffic management centre: in this way, and
following GPS information coming from the vehicle itself, real-time adaptive and priority technologies can
be applied. The integration of supervision and incident management platforms within the local UTC (Urban
traffic Control) system is essential to implement this application. The most advanced platforms are
characterized by a comprehensive approach, and the traffic manager is able to take control both of the UTC
and the supervision platform from the same graphic interface, with relevant benefits in terms of usability
and speed of the application.
Quantifiable benefits generally associated with an effective incident management program include:
Increased survival rates of crash victims;
Improved response time;
Improved air quality;
Reduced occurrence of secondary incidents;
Improved safety of responders, crash victims and other motorists.
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EasyWay is a project for documenting
Europe-wide ITS deployment on main
TEN-T corridors. The evaluation of
projects implemented through
EasyWay highlighted positive trends in
terms of its impact on road safety,
mobility and the environment.
The CHART project in Baltimore is in
the process of expanding to
automated surveillance with lane
sensors and video cameras on the
freeway system in the metropolitan
The reduction in traffic congestion
may have positive effects on public
Capacity throughputs increased by up to
20% where lanes are managed
Reduced congestion, along with reduced
accidents have resulted in CO2 savings of
5% decrease in delay (equal to 2 million
vehicle-hour per year) associated with
non-recurrent congestion (due to
The reductions in queues and, in
general, in traffic congestion has the
secondary effect to reduce fuel
consumptions and thus air pollution,
especially in urban environments.
Results measured from the EasyWay
project (See “Traffic efficiency” notes).
Injury accident savings of between 10%
and 20%, depending on the particular
Rising to approximately 60% on some
safety critical roads sections.
Table 1. Impacts of parking management systems. [*, ** or *** indicate the strength of the impact].
Incident management systems and automated incident detection systems can gain in effectiveness if
integrated into existing ITS platforms, especially if they are equipped with a geo-locating tool. The large
amount of traffic data available from road sensors and from other sources (e.g. floating car data – FCD or
extended FCD – XFCD, which consists of a FCD system which records information even about weather and
road conditions) can therefore be used for automated detections and traffic flows forecasts. ITS
technologies play a key role in incident management.
Integration with information systems (like Variable Message Sign) is the most important aspect of incident
management tools with existing ITS systems. Through this integration, an efficient information flow can be
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implemented, in order to spread information to the drivers approaching the zone of the incident. As
already mentioned, the simplest way to communicate incident information to drivers is using VMS. Most
advanced applications are based on SMS services or Smartphone-based mobile apps. Innovative services,
likely to be developed in the next years, will be based in cooperative infrastructure and V2I (Vehicle-toinfrastructure) and V2V (vehicle-to-vehicle) communication technologies, which represent the most
efficient way to share real-time updated traffic information between drivers.
Practical indications for successful deployment of incident management tools depend on several
characteristics and other factors such the kind of planned large event or the size of the expected attendees.
Below there are recommendations for the implementation of an integrated incident management strategy.
These recommendations should be adjusted to reflect and to satisfy the needs of a specific situation, in
particular as regards large events.
Effectively detect incident. The first stage of the implementation of an incident management
system is the implementation of an efficient method for incident detection. The proper vehicle and
incident detection technology has to be chosen starting from an analysis of:
o Road conditions (upgrade-downgrade, pavement deterioration, ...);
o Traffic conditions (average speed, flows, presence of queues, ...);
o Weather conditions (presence of fog, rain or snow, persistency of snow on the road
o Environmental constraints (trees along the road, bridges, tunnels, ...).
To give some examples, the upgrade of the road can seriously affect the accuracy of weigh-inmotion sensors, especially as regards vehicle classification and speed detection. In this case, other
types of sensors have to be chosen. Furthermore, the presence of trees (or other obstacles) along
the road side can cause many errors and false detections in CCTV systems. The same is for thick fog
or intense snow. On the other hand, the presence of a permanent layer of snow on the road
surface can cause malfunctions in incident light sensors.
Inform drivers. It involves activating various means (VMS, radio messages, SMS services,
cooperative technologies – V2V and V2I communication, ...) of disseminating incident-related
information to affected motorists. Motorist information needs to be disseminated as soon as
possible, and beyond the time it takes clear an incident. VMS are the most common mean for
information delivery. Despite this, more modern solutions (like SMS or mobile apps) should be
preferred in large events, because they allow the traffic manager to reach the greatest part of the
people in the area, also giving personalized instructions to the users located in different cells of the
mobile network and therefore an added value to the information service itself. Also the local
deployment of ITS devices, like portable VMS signs, can be very useful to improve the quality of this
Traffic management. It is the last phase of the incident management implementation process and
it involves the application of traffic monitoring and control measures in areas affected by an
incident. From what has been described in the “Variants” section, it is evident that the
implementation of a supervision platform (better if equipped with strategy optimization
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functionalities or if UTC-integrated) in the area of the incident represents an important advantage
for the success of incident management strategies. By using the platform, traffic operators can
efficiently manage traffic re-routing, remotely update VMS signs, coordinate emergency vehicles,
continuously monitor the situation of traffic flows in the area of the incident and, if required,
modify the signaling strategies to give priority to emergency or special vehicles.
Gowanus Expressway/Prospect Expressway – Brooklyn, New York
The incident detection system that has been implemented as part of the Gowanus Expressway/Prospect
Expressway rehabilitation project includes an automated detection system and 20 CCTVs. Other devices
deployed to support incident management functions include highway advisory radio (HAR), variable
message signs (VMS), and a construction information hotline. The benefits attributed to the deployment
and operation of this system includes a 66 percent reduction in the time required to respond to all
incidents. In addition, the time required to aid motorists with vehicles that have broken down has been
reduced by 19 minutes. (Source: Samartin, Kevin, "Under Detection," ITS: intelligent transport systems,
Automatic incident detection with inductive loops – Southampton, UK
This remote automatic incident detection algorithm is designed to detect abnormal periods of traffic
congestion existing over single inductive loop detectors. A real-time trial took place between 07:00 and
19:00 over 167 consecutive days involving 74 detectors situated along two sections of the A33 Bassett
Avenue and A35 Winchester Road in Southampton. Over this period, 181 and 334 triggers were recorded
on the A33 and A35, respectively. An independent operator log showed that over the same period, 32
incidents were recorded on the A33 and 49 on the A35. The remote automatic incident detection system
detected 69% and 92% of the verified incidents on the A33 and A35, respectively; the low detection rate on
the A33 being mainly due to five incidents which occurred during off-peak periods causing no congestion
and were therefore not detected. (Source: T. Cherrett at al., “Remote automatic incident detection using
inductive loops”, Proceedings of the ICE - Transport, August 2005)
CCTV automatic incident detection on A22 Highway – Trento, Italy
This system grants the full coverage of tunnels from Trento to the Austrian border with CCTV cameras
equipped by an high-sensitivity DSP processor, able to take hi-resolution colored images of the road. These
cameras are installed in the middle of the left lane at a distance of 150 meters (50 meters in critical section
of the highway). In case of stopping or counter-flow vehicle, fire or incident, the system alerts the operator
by a window on his platform interface showing the images of the incident. The system is also capable to
detect smoke in the tunnels and leads to a significant reduction in the time required to deploy first aid
action. (Source: C. Costa and P. Duiella, “Il piano sicurezza dell’A22”, Le Strade, pages 108-112, October
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