The document discusses collision avoidance systems (CAS) that aim to reduce accidents by alerting drivers of potential collisions using sensors and automatic braking. It describes how CAS works using cameras, radars and lasers to detect vehicles ahead and calculate braking distance needed to avoid collisions. The document outlines different types of CAS including forward collision warning, adaptive cruise control and those that automatically brake. It concludes that CAS can help reduce costly accidents by alerting drivers before problems occur.

1. Faculty of Engineering
Civil Engineering
Intelligence Transportation
Systems (ITS): Collision
Avoidance System
By: Mohammad W. Al Mohammad

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Abstract
The population explosion and the development and multiplicity of
transportation means have produced many problems that cast a heavy
shadow on human societies. The annual reports of organizations
concerned with health, environmental, and accidents matters indicate
an unusual increase in the growth rates of these negative practices,
which prompted governments to present these problems for the
treatment, where they were mocked for that Ample funds, advanced
research centers and specialized companies for the purpose of producing
and implementing techniques of sensing, sensing and indication,
designing software, and imposing general and other laws concerned with
these technologies, and restriction to strict conditions aimed at
implementation and commitment, for the purpose of the smooth flow of
safe transport inside and outside cities by all means and reducing its
negative effects on the society where it emerged. Technologies of
intelligence transportation systems (ITS) supported by advanced
communication means and information control centers working around
the clock to protect lives, property, and the environment and achieve the
best method in managing all transport operations. These systems have
been strengthened through tremendous progress in the field of
information technology and means of communication from the ground
to satellites in High orbits.

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INTRODUCTION
Intelligence Transportation System (ITS) is an advanced application
which, without embodying intelligence as such, aims to provide
innovative services related to several types of transport and traffic
management, enabling users to be better informed, and making them
safer, more coordinated, and smarter. “Use of transport networks.
Although the International Transportation System may refer to all modes
of transportation, European Union Directive 2010/40 / European Union,
which was prepared on July 7, 2010, defined Intelligence Transportation
Systems (ITS) as systems in which information and communication
technology is applied in the field of transportation. Land, including
infrastructure. And vehicles, users, traffic management, and mobility
management, as well as for interfaces with other modes of transport.
Intelligent transportation systems may improve transportation efficiency
in several cases i.e., ground transportation, traffic management,
mobility, etc.

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Collision Avoidance System
What is it?
It is a vehicle safety system designed to reduce the size of an accident. It
has many names and it is called the pre-crash system, the forward-
collision warning system, or the collision mitigating system. Several
collision avoidance systems (CAS) have been developed and used in
human-managed vehicles as well as more recently in autonomous
vehicles. Most current CAS systems perform an override function to
trigger automatic emergency braking in critical situations based on
current traffic information obtained from in-vehicle sensors or short-
range vehicle communications. These CASs focus on the critical situation
in the vicinity of the target vehicle, which means that they may have
negative impacts on the target vehicle and following vehicles, especially
when the pilot vehicle of a short-distance platoon applies harsh braking
to mitigate the impending collision hazard. This study proposes a CAS
Hazard Prediction System (RPCAS) that implements predictive
deceleration with light braking in advance to prevent a potential rear
collision by predicting collision hazards arising from the downstream
location. To evaluate RPCAS performance, the proposed system is
compared with several CASs in different vehicle tracking states based on
microscopic traffic simulations. Simulation results show that RPCAS can
effectively reduce rear-collision risk with less severe braking compared
to current CASs. Moreover, RPCAS enables vehicles arriving at the source
to anticipate a potential collision, providing them with sufficient time to
reduce their current speeds proactively. The research results indicate

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that the proposed system could mitigate the negative impacts of
previous CASs in relation to traffic and vehicle safety.
How it works?
The front collision avoidance system works via cameras, sensors, or
radars installed on the front of the car, and sometimes lasers. These
devices are all connected to a central computer, which also derives
additional information from the main computer of the car, such as speed
and braking. The radar at the top of the windshield scans the front area
of the car while it is moving and warns the driver if he approaches
another car ahead.
This is done after the front collision avoidance system calculates the
vehicle’s speed and the distance between the front car and compares it
to the stopping distance that the car needs to stop, provided by the
manufacturer.
And when the system senses that the braking distance has become
insufficient to stop the car if it is not stopped, it immediately alerts the
driver to this via an acoustic warning, shaking in the seat or steering
wheel, or flashing light in the dashboard, to stop the car in turn.
This system works in the advanced classes to automatically brake the car
if needed to avoid a collision or to reduce its consequences. In some cars,
this system also works to distinguish pedestrians and people who cross
the street in front of the car, and it is even able to distinguish a person
walking on his feet or a passenger on a bicycle, wheelchair, or pram.
When the system senses any danger, it alerts the driver to the presence
of pedestrians in front of the vehicle and asks him to reduce the speed.

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If the driver does not respond, the system will take the appropriate
measure of slowing down or a standstill. If the system senses that there
is a collision that cannot be avoided, we see it activate the brakes to
reduce the force of the accident and by adjusting the tension of the seat
belt, adjusting the head restraints, adjusting the seats, and closing the
windows and the sunroof, to reduce the impact of the accident when
colliding as much as possible.
In the same context, the Forward Collision avoidance system is most
often linked to the adaptive cruise control system, which works to
maintain the vehicle a specific distance from the vehicle in front, and
automatically increases or decreases the speed accordingly.
Types of CASs
Forward collisionwarning
It is a system that includes a visual and audible warning that the driver
is too close to the vehicle ahead. The warning depends on the distance
between the vehicle and the vehicle ahead. The warning level changes
from "safe" to "critical" as the next distance decreases.
Reverse CollisionWarning System
It is a visual and audible system that warns drivers of the possibility of
colliding with an object behind the car by sensors in the rear bumper.

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The warning is increased when the distance between the rear of the
vehicle and the body decreases.
Adaptive cruise control (ACC)
It enhances the automatic cruise control present on many new cars by
automatically maintaining a specified tracking distance for the vehicle
ahead. The distance to the previous vehicle is measured by radar, laser
systems, or both. When the vehicle ahead speed is slower than the
modified speed, the ACC system adjusts the vehicle speed to allow a
safe distance for the front vehicle.
Mitigate collisionby braking
It is an evolution of the ACC with the addition of a braking system that
increases progression by braking; These systems may also detect
obstructions inside the road and brake accordingly. The speed and
separation distance at which systems operate is determined by the
arrangement and type of sensors and the systems' ability to recognize
them.
Track guard devices
They are electronic warning systems that activate if the vehicle is about
to deviate from the lane or road. Collision times for safety-critical
changes are usually less than one second. Since the average driver's
reaction time is approximately 1 second, there is not enough time for
the driver to respond to a pre-collision warning. Since there is not

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enough time to respond to a warning, it is likely that rerouting and fault
consolidation will only be avoided by interfering systems. But these
have their own problems: how to spot the driver's intentions and how
to intervene. This could be through taking over from the driver or by
providing feedback through the steering wheel. The technical and
operational viability of these systems has yet to be demonstrated. Most
of the existing systems are warning systems only.
Conclusion
Collision avoidance systems can be a great way to help your vehicles
avoid safety incidents while also serving as a valuable tool to train
drivers on safety best practices. Because these monitoring systems use
sensor technology to detect impending collisions, they can alert drivers
of a problem before it is too late. Plus, they can have a significant
impact on your bottom line: collision avoidance systems can help
reduce the number of costly safety-related incidents that occur across
your fleet.

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