traffic signal control using

8/3/2019 Traffic Signal Control Using

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Traffic signal control using

fuzzy-logic

Submitted by-

Ankit Agrawal

Amit Kumar

Harshal Arora

Harpreet Anand Guided by-

Neha Verma Prof. D. L.

Bhombe


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INTRODUCTION

Traffic congestion causes significantdecrease in both traffic throughput andtravel speed.

The conventional stop and go drivingregime causes increase in accidentsfrequency, increase in consumption,air pollution.

Our project is based on an attempt toexplore a new method to improve theflow of traffic control using fuzzy logic.


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Why fuzzy logic in traffic control?

Traffic signaling at a given intersectionis not truly adaptive because thesettings can only be altered manually

or by traffic control center. One of the desirable features of traffic

controllers is to dynamically effect the

change of signal phase durationswithout looking up pre-compiledinformation.


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Fuzzy logic

Fuzzy logic is technology thattranslates natural languagedescription of design policies into an

algorithm using mathematical model. This mathematical model implements

the flexibility of human logic-

abstraction and thinking in analogiesin engineering solutions.


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It consist of 3 major sections

Fuzzification

fuzzification means using themembership functions of linguistic variables tocompute each terms degree of validity at a specificoperation point of process.

Fuzzy logic interference using IF-THEN rules- Allnumerical values have to be converted intolinguistic values. Production rules consist of acondition (IF-part) and a conclusion (THEN-part).

IF-part can consist of more than one preconditionlink together by linguistic conjunctions like AND &OR. Each rule is assigned a degree of support inthe interval [0,1] representing individual importanceof the rule.


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Contd..

Defuzzification - Membership function are used to re-translate the fuzzy output into crisp value. This re-translatingis known as defuzzification. First a typical value is computedfor each term in the linguistic variable and finally a bestcompromise is determined by balancing out the results using

different methods.


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System designingmethodology


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Fuzzy Logic Controller (FLC)

In order to accommodate turningtraffic at a single cross junction, acomplete control cycle should consist

of a minimumof four phases, as shownin Fig. 1, allowing traffic from the fourphases (i, i = 1, 2, 3, 4) to pass

through the junction in turn.


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The following assumptions aremade in this junction setup. All vehicles are right-hand driven, hence

left-turning traffic does not block thetraffic of the opposite direction.

The interdependencies of the flow rates

among the traffic streams are assumedto be minor and, hence, not accountedfor in this study.

Vehicle arrivals are stochastic in nature

with uniform distribution and the meanequal to the flow rate. Saturation flow for each arm at thejunction is d vehiclesper second.


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Each phase has a minimum of 10 s ofeffective green time.

The order of the traffic phases within acycle is well defined and fixed.

The number of vehicles that the junctioncan hold at its arms is not bounded inthis study.

The traffic at one arm is collectivelyregarded as one stream or lane, and thedischarge rate of vehicles is the same asthe saturation flow.


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OBJECTIVE

The objective of the FLC is to determinethe effective green times for each phase,in such a way that the totaldelay at thejunction is minimized.

To gain the dynamic traffic data for thecontroller, vehicle detectors must beinstalled at the junction.

The current queue length and flow rate ineach traffic stream are the mostimportant information to the controller.


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. To count the number of vehiclesentering the junction for flow rateprediction, a vehicle detector must be

installed at a distance from thejunction on each arm.


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It is therefore possible to establish thequeue length and the flow rate of eachtraffic phase.

Figure shows the junction setup withvehicle-detector locations.

Miscounting a long truck as two vehiclesmay happen, but the length of a truck is

similar to that of two vehicles. Hence, theimpact on the actual length of the queueis not significant.


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DisplayTrafficUnit

Transportation system

Drivers,vehiclesstreet

Measurementunits-

Vehicledetectors

Control system

traffic signal control using

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