Implementation of RFID Technology in Parking

Lot Access Control SystemG. Ostojic, S. Stankovski, M. LazarevicFaculty of Technical Sciences Novi Sad,

Trg D. Obradovica 6, 21000 Novi Sad, Republic of SerbiaVukica Jovanovic

College of Technology, Digital Enterprise Center, Purdue University,1419 Knoy Hall, N.Grant St.,West Lafayette IN 47907, USA

Abstract-Parking plays an important role in the traffic systemsince all vehicles require a storage location when they are notbeing used to transport passengers. Whether it is a parking lotor on-street parking there is a problem of parking revenueconvenience. Implementation of the RFID technology could be agood solution for this problem.

I INTRODUCTION

Radio Frequency Identification (RFID) is becoming animportant identification technology in applications such asinventory management, security access, personnelidentification, factory automation, automotive toll debiting,and vehicle identification to name just a few.

During the last four decades numerous parking searchmodels have been developed [1, 2, 3, 4, 5, 6, 7, 8, 9, and 10].Since parking plays an important role in the traffic system oneof the problem concerning this area is parking revenue. RFIDtechnology was chosen for the implementation in parkingsystem of city ofNovi Sad, Republic of Serbia.

Territory of the city of Novi Sad encompasses the surfaceof 702.7 km2 with population of about 310,000. We anticipatethat there are more than 130,000 vehicles. Having this inmind there is a huge traffic and parking problem in city ofNovi Sad.

At Faculty of Technical Sciences Novi Sad, Department ofTraffic Engineering, the stationary traffic study was donewith the analysis of the status of stationary traffic anddefinition of solutions for occupation of public runningsurfaces, analysis and exploitation of public garages andparking lots.

According with the stationary traffic study new parkingsystem is released in 2005.

II PARKING SYSTEM IN CITY OF NovI SAD

There are different types of parking system in city of NoviSad: on-street parking, parking lots and garages. On streetparking is organized in three zones: red, blue and white.Parking revenue is done by a Parkomat, SMS (Short MessageService) message over mobile phone and by parking ticket.Instead of parking revenue collectors there are parkingcheckers (checking parking price payment).

Parking revenue for parking lots and garages is done byparking collectors, because the parking price varies with thetime spent on a parking lot or in a garage.

Parking operators face a number of challenges such as:1) The inability to accurately and intelligently identify,

collect and record the data of the vehicles that enter and leavethe parking lot then processing this data to better analyzetraffic patterns and facilitate client billings.

2) Need to increase the security (and user integrity) of theparking lot.

3) Adding human resources, especially in peak traffic timesthat burdens operating costs and reduces profitability.

4) Line-ups created for parking payments, especially duringpeak traffic times that reduces the service levels to customers.Automated parking revenue systems enable convenience

when dealing with already mentioned challenges.

A. On-streetparkingOn-street parking places are located in over 90 streets in

center of the city of Novi Sad. Traffic in these streets isunobstructed.A parking place user sends SMS message by a mobile

phone to an adequate number (for the parking zone). Messagecontains license plate number (e.g. ,,NS1 1 111 1").

Every message sent by a parking place user is forwardedfrom mobile operator (Telenor or Telekom) to company forparking revenue server over the Frame Relay (see Fig. 1.).Afterwards, confirmation/failure message is sent to a userabout parking revenue. If a user has correctly entered licenseplate number and has enough funds on his/hers accountneeded amount of money is reserved for parking revenue andconfirmation SMS message is sent to a user. Moneyreservation is accomplished by server which sends query tomobile operator billing system over Frame Relay (see Fig. 1.).

SERVER ROUTER ROUTER

FRAME_RELAY

Fig. 1. Communication between server and mobile operator server.

SERVER ROUTER ROUTER

ft [MOBILEOPERATOR

PDAFRAMERELAY

ControL center

Automatic barries

_....

Fig. 2. Communication between PDA and server.

If a user gets confirmation message the reserved money isobligated, and if, for any reason, user doesn't getsconfirmation message in 5 minutes transaction is stopped andreserved money is released. All messages are sent to a user byFrame Relay to mobile operator and then from SMS mobileoperator center to user over GSM (Global System for MobileCommunications).

Checking of the parking revenue payment is done byparking checkers. They are using PDA (Personal DigitalAssistant). They print penalty ticket and enter license platenumber and send query to database. If a user haven't paidparking price or the time for parking is overdue a parkingchecker enters data for the parked vehicle (license platenumber, vehicle type, time and place etc.). These data is sentover GPRS (General Packet Radio Service) to mobileoperator and after that over Frame Relay to server (Fig. 2.).From database server, license plate number is sending to

the police (in text file), and the police sends back vehicleowner data to the database.

Every penalty ticket has a unique number. On the PC(Personal Computer) there is an application for selectingrecording penalty tickets from E-bank database (MicrosoftAccess) and transfers it to database on the server(PostgreSQL).

B. Parking lots and garagesThere are several parking lots and garages which are

dislocated all over city of Novi Sad. They have one or severalentry/exit. Parking entry/exit on these parking lots is beingcontrolled by arm barriers. Parking revenue is done byparking collectors, because the parking price varies with thetime spent on a parking lot or in a garage.A parking place user stops a vehicle on inductive loop (in

front of arm barrier) and with a hand presses pushbuttonplaced on a control center side. Afterwards arm of theautomatic barrier lifts thus enabling entering a parking lot.Also a user gets printed parking ticket with encoded enteringparking lot (or garage) time (see Fig. 3.).

On entry barrier there is display with indicating light(red/green) with display. On a display number of free parkingplaces is shown. If there is no free parking places arm of abarrier will not lift. There is a GPRS communication betweenbarriers controlling systems, when the entry and exit barriersare dislocated. Exit barrier, sends a signal to an entry barrierwith every arm lift. According to received signals controlsystem calculates number of free parking places on parkinglot or garage and sends number to the display.

Exit

Parking lot

Indicating Lights (red I green)

Induot ive LoopPu button

rFIreader

Enter

Fig. 3. Entry/exit parking lot (garage) system.

When a user of a parking place wants to leave a parkinglot or garage he/she stops a vehicle on exit inductive loop (infront of arm barrier) and gives a parking ticket to a parkingcollector. A parking collector then reads a barcode printed ona parking ticket (with a barcode reader). Afterwards, timesspend on parking place and a price for the parking service isdisplayed on the PC monitor. Those data could be seen byboth a parking collector and a parking place user. Afterpaying for the parking service, parking collector prints areceipt and exit barrier arm lifts, so the user can leave aparking lot or garage.

III CONTROL CENTER OF A PARKING LOT OR GARAGE

Regulation of vehicle entry/exit parking lot or garage isaccomplished by the control center. In control center basiccomponent liked to all the others is programmable logiccontroller (PLC) FESTO, type FEC FC440. This PLC has 16digital inputs and 8 digital outputs, 2 serial ports and oneEthernet interface. Other components connected on PLC atentry side of parking lot are: inductive loops, capacitivesensor, barcode printer, display and GSM modem (see Fig.4.).

GPRS communication between entry and exit barriers isaccomplished by Siemens MC 39i modem connected withTTL RS232 cable to EXT port (serial port-extensioninterface) of PLC.

The exit control center of the parking lot or a garage alsohas PLC, but there is a difference with the componentsconnected to it. Besides inductive loop and GSM modemwhich are also present in the entry control center, there is aPC, a receipt printer and barcode reader (see Fig. 4.).

According to the momentary status of inputs (sensors) likeinductive loops and demand for printing ticket at the entrypart of a parking lot PLC sends output signals to arm barriersand semaphore (indicating lights). Inductive loops are used todetect metal objects (vehicles in front, beneath and behindbarriers).

Exit

n 4

GPRS

G~P1RS

Display

Fig. 4. The entry/exit control center of a parking lot or garage.

A ticket printer is connected by RS232 cable to first serialport while display for indicating number of free parkingplaces at the parking lot is connected to the second.

Communication between the PC and PLC is over Ethernetinterface (twisted pair interface- I OBaseT) on a switch.

On a PC there is application for trifling parking service(according to the time spent on a parking lot or garage) whichuses PostgreSQL database. Also, there is an application thatgives the command to the exit barrier to raise the arm. ThePLC is programmed according to IEC 61131-3 standard.

IV IMPLEMENTATION OF RFID TECHNOLOGY IN CONTROLCENTER OF A PARKING LOT OR GARAGE

Since RFID technology is contactless identificationtechnology a suggestion was given to use this technology inparking systems. Advantages of RFID technology incomparison to other technologies are:

* No need for physical contact between data carrierand the communication device

* Tags can be used repeatedly* Robust tags can withstand extreme conditions and

temperature* Low maintenance costs* Tags available in a range of types, sizes and

materials* Non-line-of-sight communication makes it possible

to read and write Tags in dirty conditions.* RFID tags may be read by the RFID system at one

time.* Extremely low error rate.

We have implemented RFID technology in entire parkingsystem of city of Novi Sad, meaning both on-street parkingand parking lots and garages, thus creating intelligent parking

control management system which integrates RFIDtechnology, automatic control technology and applicationssoftware.

We have chosen RFID system that is working onfrequency of 13.56 MHz because:

* 13.56 tags are less expensive due to their limited coilrequirement and

* Some 13.56 MHz tags are anti-collision.

In designed parking system verification of parking servicerevenue is done by using passive RFID tags (ISO 15693).There are several types ofRFID tags-tickets:

* for invalids (free of charge),* for people living in parking zone (monthly or yearly

payment but only for limited parking area),* for all others (golden card, only for one month but

for all garages, parking lots and on-street parking,see Fig. 5)

Fig. 5. Golden card - RFID tag.

Reading distance for these passive RFID tags is 7 cm.Their weight is 3.4 g, so they are light, easy to use and tocarry with the user (they look like a credit card). Also thesetags are read/writable (64's block memory space for userdefine, each block can be written 4 bytes data).

A. Entry control center ofaparking lot or garageA parking place user stops a vehicle on inductive loop (in

front of arm barrier) and puts RFID tag in front of a RFIDreader (mounted on a control center, see Fig. 3.). Afterwardsarm of the automatic barrier lifts thus enabling entering aparking lot. In this case he or she doesn't get printed parkingticket with encoded entering parking lot (or garage) time.

There are defined terms which must be achieved in orderto lift the arm of an entry barrier like:

* Vehicle must stop on inductive loop.* Data written on RFID tag must be correct like:

* Validity period (day, month, year),* Integrity,* Is the user vehicle out of the parking lot (or not).

RFID reader is connected by RS232 cable to EXT port ofPLC. PLC is programmed to communicate with RFID readerand to send read and write commands to RFID reader.Principle is next: after a parking place user stops a vehicle oninductive loop and puts RFID tag in front of a RFID reader,reader query's a RFID tag. The RFID tag detects theinterrogating signal and transmits a response signalcontaining encoded data back to the receiver. This data is:UID - Unique Identification-encode check, validity period -locked data for date, time, and year, so that the tag can beused only in defined period (after locking this data no one canunlock these blocks for reuse), check bit (one block memory)to determine is the user's vehicle already is in the parking lotor not. This check is practiced for prevention of malversation.One user of a parking place could borrow RFID card toanother user.

MiGPRS

PLC software analyses gathered data and if the UID iscorrect, if validity period is correct and the user's vehicle isnot already in the parking lot sends a signal to barrier to liftan arm and sends a command to RFID reader to write onRFID tag information that the vehicle is entering parking lot.While PLC is processing information, green led diode isblinking, thus informing a user of activity of checking andwriting information on tag process. After writing data toRFID tag green led diode stops blinking and user can drive into parking lot (or garage).

If one or all of the named data are not correct, system willinform a user by lighting red led diode. An arm of a barrierwill not lift a user can't enter in a parking lot. If a user stillwants to enter in a parking lot (or a garage) he or she mustpress the pushbutton, placed on a control center side andfollow the procedure already mentioned above.

B. Exit control center ofaparking lot or garageWorking procedure at the exit barrier is next: after a

parking place user stops a vehicle on inductive loop and putsRFID tag in front of a RFID reader, reader query's a RFIDtag. The RFID tag detects the interrogating signal andtransmits a response signal containing encoded data back tothe receiver. This data is: validity period and check bit todetermine if the user's vehicle is in the parking lot or not.

PLC software (see Fig. 7.) analyses gathered data and if avalidity period is correct and the user's vehicle is at theparking lot sends a signal to barrier to lift an arm and sends acommand to RFID reader to write on RFID tag informationthat the vehicle exit's the parking lot. While PLC isprocessing information, green led diode is blinking, thusinforming a user of activity of checking and writinginformation on tag process. After writing data to RFID taggreen led diode stops blinking and user can drive in toparking lot (or garage). In this case a parking place userdoesn't pay for the parking service and doesn't get a receipt.

RFIDRI IL)RFIDretod&r

Fig. 6. New control center of a parking lot or garage.

V CONCLUSION

Fig.7. PLC software for control center of a parking lot or garage.

Ifnamed data are not correct, system will inform a user bylighting red led diode. An arm of a barrier will not lift a user

can't exit a parking lot. In this case a parking collector checksan RFID tag to determine the problem. If a problem is relatedwith the validity period parking collector calculates revenue

for the time spent from the end of the validity period till now.Calculated time and a price for the parking service are

displayed on the PC monitor. Those data could be seen byboth a parking collector and a parking place user. Afterpaying for the parking service, parking collector prints a

receipt and exit barrier arm lifts, so the user can leave a

parking lot or garage. If the problem relates to the value of thecheck bit then a user of a RFID tag an authorized institutiondeals with this problem.

Parking collectors at parking lots and garages are

authorized to visually check, every now and then, validityperiod and quality of graphics printed on a RFID tag (in case

of a forgery). In this way, parking collectors are checkingparking revenue for the on-street parking (for the users whohas RFID tags).

C. SummaryNew control centers of a parking lot or garage in city of

Novi Sad, where we implemented RFID technology has beenin use since January 2007.

Till now collection of the parking service tariff has beenincreased for 17%. For the on-street parking, one of thereasons for the increase is simple procedure for getting RFIDtag (approximately twice as much time needed for buying a

ticket for on-street parking). People realize that the time theyhave to spend waiting in line to buy the tickets (sometimesseveral tickets for different parking zones) they can spenddoing something else.

For the parking lot or garage users, one of the reasons forthe increase in parking service tariff collection is much lesstime spend waiting at the entry and exit barriers. Also theydon't have to worry about amount of time spend at parking lotor do they have enough cash to pay for the parking service.

Implementation of the RFID technology, in an existingparking lot access control system, has given benefits to allinterest parts (the Parking Operator, parking place users andparking collectors).

Parking Operator has gain robust system, easy to operate,easy for maintenance, with the reliable RFID tag-ticket checkfor the prevention of malversation. Also, RFID reader isplaced in a way that it doesn't violate exterior. Till nowcollection of the parking service tariff has been increased for1700.

People using parking place are spending much less time inwaiting in line to buy the tickets for the on-street parking andmuch less time waiting at the entry and exit barriers of aparking lot or garage.

Parking collectors that are working at parking lots andgarages are much less involved in collecting tariff. They areonly active when dealing with parking place users who don'thave correct RFID tag-ticket and, of course, when they haveto charge for the parking place users who don't have RFIDtag-ticket.

Future research will be directed towards the designing aparking system so that a parking place user will be able just todrive thru and enter/exit parking lot or garage. Also we willtry to automate the in and out privileges of the subscriber andthen transfer this data to the enterprise software for the trafficanalysis that will allow optimization of the human resourcesneeded for traffic flow in and out. For customer payment, theRFID tag could be read to debit a pre-pay system or chargethe parking services against a credit card. All of this willfacilitate customers entering and leaving and this improvesservice levels and increases capacity in the parking lot. Thesebenefits will drive higher revenues.

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