Accident
Warning System at Intersection
Requirements Specification
Special Restrictions
Principle of Operation
Speeding Car OnBoard Unit consists of a GPS which
constantly determines the location and speed of the car in which the unit is
located. This information is logged by a laptop and sent to the transceiver,
which sends it to the Roadside Unit. Roadside Unit The Roadside Unit transceiver
receives the speed and location information from the OnBoard
Unit. It verifies if the light is turning red anytime soon, and if it is then
it calculates whether the speeding car will run the red light. If it will run
the red light, then a warning signal is sent to the transceivers of all OnBoard Units. Traffic Light We are simulating the traffic
light on a microcontroller. The microcontroller has an external clock which
helps it keep track of the period of time the light should remain a certain
color. It is directly connected to the Roadside Unit laptop, to which it
sends a control signal defining the point after which the Roadside Unit needs
to consider all messages from the OnBoard Unit as
Event Messages. Warning Signal If the speeding car
will run the red light, then a warning message is sent from the Roadside Unit
transceiver to the transceivers on the OnBoard Units
of the speeding car as well as the waiting car.
Input
There are two inputs to the Accident Warning System. 1. GPS This input contains information
on the speed and location of the car in which the GPS is located. It is
constantly sent to the Roadside Unit. 2. Traffic Light This input allows the Roadside
Unit to judge when to regard the speed and location information from the OnBoard Unit as Event Messages. Output
There
are two kinds of output from the Accident Warning System. 1. Warning Signal A warning signal is sent from
the Roadside Unit transceiver to the OnBoard Unit
transceiver of the speeding and waiting cars in order to warn both cars that
the speeding car is about to run the red light. 2. No Action If the speeding car will not run
the red light, then no action is taken by the Roadside Unit and hence no
warning signals are received by the OnBoard Units. Acceptance Tests
The acceptability test
is to ensure the successful execution of the real-life demonstration of an
accident warning system involving a single speeding car. If the car is about
to run the red light, then a warning should flash on the laptops of the
speeding and waiting car. If it is not going to run the red light, then no
action should be taken. |
|
|
|
|
|
|
|
|
|
This page is maintained by Richa
Prasad.
© 2007
University of Massachusetts Amherst •
Amherst, MA 01003