22-11-2012, 01:35 PM
AN IDEA TO AUTOMATICALLY DETECT HIGHWAY ACCIDENTS AND TO CONVEY THE INFORMATION ABOUT THE OCCURRENCE OF THE ACCIDENT TO THE NEAREST POLICE STATION AND HOSPITAL USING MOBILE COMPUTING.
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Abstract
Statistical reports show that, the “Absence of timely medical care” accounts for a large percentage of fatal accidents on highways, because there is no way of getting immediate first aid. Moreover, due to the occurrence of the accident, heavy traffic builds up until the policemen are summoned for clearance. Our system mainly aims at the automatic detection of highway accidents and the conveyance of a message to the nearest police station and to the hospital regarding the location of the accident, to initiate immediate recovery and traffic clearance. Incoming vehicles are also informed in advance of these accidents/congestions; so that those drivers may take another route/appropriate actions. Special sensors capable of forming an ad-hoc network along the movement of the vehicle (enabled with GPS), locate the area of accident. Air bag sensors in the vehicle detect the acceleration changes during the accident and convey it to the special sensors employed, through the bidirectional radios attached to the vehicles. The sensor transmits this message, along with the location information, to all the remaining sensors and to the access point server, from which the hospital and police station are notified through a fax message. All the other vehicles, on receiving the accident message from the remaining sensors on the road (through their bidirectional radios), take up another route to prevent traffic jam and to ease the arrival of the ambulance and the police vehicle. Thus immediate first aid for the injured and speedy clearance of the accident area may be ensured.
INTRODUCTION
Present traffic monitoring systems use expensive devices such as video cameras, magnetic loop detectors that are difficult to deploy and not very scalable. But our solution uses inexpensive agents. The use of vehicular networks for traffic monitoring requires advanced sensors in the vehicle themselves. Many individuals are not willing to bear the extra cost of fitting these special devices to their vehicles. Vehicular network solutions differ greatly in their design, protocol and implementation. As such a vehicle that uses one vehicular solution will not be able to communicate with other vehicles along the road unless they all implement the same solution. This can be a very grave problem. Our solution is generic and does not face the above problem. Sensors are very resource constrained in terms of power, memory and computation thus reducing the resource requirements of the system drastically. Vehicles on highways usually travel at high speeds between 65 to 70 mph. They need to be informed of the accident/congestion up ahead as quickly as possible before it is too late. Our solution senses accidents as soon as they occur and communicates this information to the rest of the relevant network as quickly possible. Also the users are often unwilling to learn (or just plain lazy) how to use new systems.
DESIGN
Our solution introduces two very unique ideas:
1. It integrates an ad-hoc sensor network with a vehicular network to create an effective, energy-efficient traffic accident detection and notification system. As far we know this has never been done before.
2. We also introduce the new concept of Virtual Group and Watchdog Group of sensors that will track the motion of a car and will greatly increase the reliability of the network while making sure that we have less energy-consumption by the sensors
Sensors placed along-side highway roads, are active and listening when there is traffic movement, detect any traffic accident and communicate this message to neighbouring sensors, which will in turn notify incoming vehicles of the accident up-ahead.
DETECTION OF ACCIDENT
Air-bag sensors [2] in cars that detect the accident will trigger the car radio to broadcast accident alarm message. The sensor closest to the car that receives the alarm message will wake up the sensors behind it (if they are already not awake).
The sensor will then broadcast an Event Notification message with the TTL field set to a fixed value so that the message does not propagate further than is required. The message (containing location details) eventually reaches the special sensor through various hops which then transfers the message to the nearest access point [3] from which the message is transferred to the server.
The server sends a fax message containing the location of the accident obtained from the sensor input, to the nearby hospitals and police station thereby alerting them. (Fig.4)
SPECIAL CASES
If an accident occurs in a very long stretch of highway with no exits, the other vehicles need to be informed before it leaves all exits behind. Relay of message from one sensor to another takes a long time until it reaches the car to be informed. Here we can use the access point to convey message directly to the sensor closest to next-to-last exit (as far in advance as feasible).
Normally sensors communicate with each other on a per- hop basis. If a sensor goes down, it finds the neighbouring sensors across the road and bypasses the down sensor. The overhead of extra sensors is a small price to pay for greater reliability.