NEW MOTORWAY TECHNOLOGY UNDER TESTING

R Zimmermann and B Neumeyer

Our desire for transport and mobility is still so strong that traffic increases faster than the required traffic routes. This applies to both passenger and freight traffic, and not only to road transport but also to transport by rail or air. The number of congestions will thus increase, traveling times will become longer. This nega- tive development of traffic may, however, be opposed by the increased application of telecommunications and information technology in the field of traffic, or in short "telematics in traffic".

Requirements concerning telematic systems in traffic can be derived from applications like traffic informa- tion, parking space information, electronic route guidance etc. Further requirements are necessary if telematic systems are also used for payment procedures. for example for advance booking of a parking place and the subsequent payment of the parking fee, or for safety-relevant applications such as the control of access per- missions for company premises. Very high requirements must be fulfilled if such payment and control proce- dures are to be carried out safely and correctly even during a fast motorway ride (up to 250 kmh) and during the process of changing lanes.

Field Test "New Motorway Technologies" in Germany

Since the European Community will permit the introduction of route-related motorway fees in all member states from January 1, I998 onwards, the Federal Ministry of Transport has decided to perform the field test "New motorway technologies" in order to determine the feasibility of such a complex telematic system.

The field test, which was started on May 2, 1994 will be continued until April 30, 1995 on the A555 between Bonn-Nord and Wesseling (in direction Cologne). According to preliminary technical investigations by the

Rheinland, out of 125 parties interested and 19 serious applicants, 10 companies and groups are actually participating in the field test at their own expense (One of them is the consortia Dornier-Marconi with its partner Autostrade). Functionality and technologies employed by the ten participants differ considerably. It is, however, not the aim of the field test to determine a "winner" but to examine this broad spectrum in practical operation, and to use it as the basis for a technical specification concerning the introduction of a full-coverage automatic toll collection system in accordance with the European standardization.

Automatic Toll Collection

Motorway fees have been charged in the large neighbouring states in the EU, Italy and France, since the be- ginning of the motorway construction in these countries. This is. however, carried out by manual toll col- lection requiring a large staff and large areas for the toll stations. In Germany as well as in the UK, no space has been provided for that purpose, toll collection must therefore be carried out completely automatically and without impairing the traffic flow. In Italy and France too, the increasing traffic and the impossibility to in- crease the number of lanes requires the introduction of lanes with automatic toll collection.

The following describes how the automatic toll collection could be carried out in Germany from January 1, 1998 onwards. This procedure does not correspond to any of the current field test systems, it is a variant with relatively low investment costs, an extremely high efficiency and fulfilling all the requirements concerning data protection and privacy. The ideas have been furnished by various participants in the field test.

R. Zimmermann and B. Neumeyer are with Daimler-Benz Aerospace Dornier, Friedrichshafen, Germany

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Data communication between vehicle (OBU) and gantry on the A 555

Each vehicle driving on the motorway is equipped with an On Board Unit (OBU). This may be an "electronic credit card" with an integrated microwave antenna or a little box which is permanently installed in new cars, or attached at the front screen by means of suction cups (for example behind the inside mirror). The OBU is provided with a random number and an identification of the vehicle type (for example passenger car) and contains in the high end version a card reader for the insertion of a debit card (pre-paid mode). If this is inserted, the current state of the credit balance is indicated on a small display unit of the OBU. Furthermore, the OBU contains a receivinghansmission equipment for data communication in the microwave range at 5.8 GHz from and to permanent transmittersheceivers (beacons) which are part of the so-called "roadside equipment".

Upon the entrance to the motorway, a small transmitter transmits to the OBUs of all entering vehicles the number of the motorway, the number of the motorway entrance, the direction of entrance, date and time. This information is encrypted in such a way that it cannot be falsified. The OBU stores these data. If the vehicle leaves the motorway, a further transmittedreceiver located in the exit curve inquires the identification of the OBU, the stored data record, the identification of the debit card and the credit balance on the card. Then the fees to be paid are calculated, the OBU is requested to deduct the amount from the debit card, and the reduced account is inquired again for control purposes. (In the credit card type the account number is inquired and the proper account will be charged.)

This road pricing process is called "closed system". Data communication only takes place at motorway entries or exits. There, the vehicles are relatively slow (below 100 km/h) and thus remain in the communica- tion range of the beacon for a relatively long time. In most cases the road has only a single lane and the road- side equipment can thus be simple and cost-efficient. The fees are charged only once per ride and they may be very flexible. For example, for short routes (entry and exit are known) at sections susceptible to conge- stions, additional fees may be charged at the corresponding time of the day, and at other times they may be reduced in areas with a bad national road infrastructure. This process meets all the requirements concerning data protection and privacy since the identification of OBU and debit card as well as the debiting procedure are completely anonymous. If a vehicle is stolen, the owner may disclose the identification of the OBU. It is then transmitted to all accounting stations which inform about each debiting procedure and thus about the corresponding location of the vehicle (respectively the OBU).

Protection against Manipulation of Motorway Users "Unwilling" to Pay

The experience gained on foreign motorways with (paper) entry vouchers and payment upon exit shows a variety of manipulation possibilities for motorway users "unwilling" to pay, which might be used in a similar

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way for the "closed system" described above. For example, someone driving from Hamburg to Munich-East exchanges his OBU on the way with a friend driving from Munich-Freimann to Hamburg-Harburg. At the exit he pays for the short route Munich-Freimann to Munich-East, his friend pays for the short route in Ham- burg. Similar "saving effects" can also be achieved if several OBUs are utilized in the same vehicle. This re- sults in a considerable loss of income for the motorway operator.

This can be remedied by an "open system" in which charging for the corresponding section is carried out between two entry points like, for example on the test route A555. That means, many debits have to be made (on an average every five kilometers), and the road infrastructure will be more complex on account of the high speeds and the several lanes. The advantages of both systems can be used, if the "closed system" de- scribed first is supplemented by the complex infrastructure of an "open system" only in front of each motor- way junction or other possibility to change the direction. In the case of longer routes, fees are charged from the entrance to the first junction, from junction to junction, and from the last junction to the exit. Thus, there are no losses of income. The more complex infrastructure (comparable with that at the A555) in most cases does not require any larger construction measures since there are several gantries in front of a junction which could be used for the reception of transmitters/receivers.

Detection of "Non-payers'' and "Incorrect Payers"

If all vehicles are equipped with correct and properly working OBUs, the motorway operator has no losses. If however, a vehicle has no OBU, or if the latter is switched off, this "non-payer'' is not detected by the beacon. Therefore, a detector is required at any toll station in order to determine if and where there is a vehicle, and a computer comparing if the vehicle pays the fees. Detection alone is, however, not sufficient, since there will be different fees for different vehicle classes. A truck might use a cheaper passenger car OBU, and would then be an "incorrect payer". Therefore, the detection equipment must also verify if the vehicle class transmitted by the OBU is correct. For example this is carried out by means of a range image camera (RIC) determining the vehicle height profile on the basis of laser-pulse run time measurements.

Non-payers and incorrect payers are detected, and shortly afterwards the rear part of the vehicle can be photographed with a video single-shot camera and an infrared flash unit. For the further prosecution this picture with the rear number plate is available as a complete digital data record including the measured height profile, the determined vehicle class and the data transmitted during the payment process. No pictures of correct payers are taken. This monitoring is generally carried out at each toll station immediately during the debiting procedure. There is no impairment or disadvantage to correct payers, but non-payers or incorrect payers will be certainly detected, even if particular monitoring devices have failed (or are missing). On an average of 21,000 vehicles per day using a track with several lanes, one monitoring process will cost less than 1 Pfennig per vehicle, which is infinitely small compared to manual sampling controls or to mobile monitoring vehicles. Furthermore, the process does not result in additional traffic or environmental impacts, and it cannot be avoided by a changed or even dangerous driving behaviour. It is economic and very efficient and ensures correct payment of the motorway fees by all vehicles without necessity of extremely high fines.

E 1995 The lnstituhon of Electrical Engineers Printed and published by the IEE, Savoy Place, London WC2R OBL, UK

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Range image pictures of two vehicles