THE PROSPECTS FOR ELECTRONIC FEE COLLECTION (EFC) USING VEHICLE POSITIONING SYSTEMS (VPS) erp1110 paper on VPS for Turin World Congress.doc by Ian Catling, Ian Catling Consultancy, Ash Meadow, Bridge Way, Chipstead CR5 3PX, U.K., telephone: +44 1737 552225, fax: +44 1737 556669, email: ic@catling.com SUMMARY Road User Charging (RUC), Electronic Road Pricing (ERP) and Electronic Toll Collection (ETC), collectively known as Electronic Fee Collection (EFC), are increasingly important ITS applications. The technical development of EFC has been largely focused on Dedicated Short-Range Communications (DSRC). The combination of an on-board positioning capability, typically using the GPS satellite system, with on-board processing and mobile communications now offers a viable alternative technology option for EFC. Recent trials in Hong Kong indicated that this approach generically referred to as based on Vehicle Positioning Systems (VPS) is fast becoming a viable alternative to DSRC, particularly where there are concerns over the environmental intrusion of roadside DSRC infrastructure and where integration with other Intelligent Transport Systems (ITS) applications is an important feature. This paper describes VPS technology for RUC, and discusses its development in Germany, Switzerland, Denmark, the UK and, in particular, the Hong Kong Electronic Road Pricing Feasibility Study. It describes the INITIATIVE project that is demonstrating aspects of interoperability between DSRC and VPS-based EFC, and summarises the development of standards for VPS-based EFC within ISO and CEN. Finally it compares the advantages and disadvantages of DSRC and VPS for EFC and discusses the prospects for widespread interoperable implementation of VPS-based EFC systems. INTRODUCTION Until recently, most approaches to electronic tolling, electronic road pricing and road user charging, collectively known as Electronic Fee Collection (EFC), have been based on the concept of shortrange communication between an in-vehicle unit and roadside equipment, using Dedicated Short- Range Communication (DSRC). An alternative approach, rapidly gaining credibility and interest, is based on an in-vehicle positioning capability and has been referred to by a range of terms, including the following: GNSS / GSM (Global Navigation Satellite Systems / Global System of Mobile communication) used by the European Commission GNSS / CN (Global Navigation Satellite Systems / Cellular Networks) used by the ISO / CEN standardisation group working in this area GPS / GSM (Global Positioning System / Global System of Mobile communication) used in a variety of sources Autonomous systems used by CARDME, the European 'Concerted Action on Road Demand Management in Europe' group SNMTT (Satellite Navigation and Mobile Telephone Technology) also used by CARDME Wide Area Systems used by the University of Newcastle who have carried out research in this area
MPS (Mobile Positioning Systems) used by the UK Department of the Environment, Transport and the Regions (DETR) VPS (Vehicle Positioning Systems) used in the Hong Kong Electronic Road Pricing Feasibility Study The terms VPS and MPS do not prescribe the means of positioning, but in practice all developments to date have used GPS as the location means. VPS-BASED EFC THE TECHNOLOGY The basic concept of the VPS approach to EFC is that the In-Vehicle Unit (IVU) should contain a means of locating itself within a network or charge area. Typically this is done using the Global Positioning System (GPS) of satellites. The IVU also contains details of the appropriate charge structure and is able to determine when charges should be applied. When a charge is generated, it can either be deducted directly from a smart card inserted into the IVU, or stored for later transmission and debiting to a centrally-held account. Although not necessary in order to perform the basic charging function, most VPS implementations to date have included a mobile communication link, which provides the following: A means of updating the charging system data stored in the IVU; Transmission of charge generation data at appropriate times (not necessarily immediately the charges are generated); System diagnostics and/or health/status message transmission; Transmission of digital certificates for enforcement purposes; and A continuously available communication medium for integration with other ITS applications and services. As with almost all EFC systems, enforcement is based on the capturing of images of the licence plates of violating vehicles. Unlike a DSRC-based system, a VPS system does not have fixed charge points with gantries and system components installed at the roadside for charging purposes. The approach taken in the recent field trials in Hong Kong was to envisage both a small number of fixed enforcement sites, which might be based at key high-flow points of the network, and a number of portable enforcement sites, which could quickly be set up at the roadside to provide a form of random enforcement. Figure 1 (taken from the Hong Kong ERP Feasibility Study) illustrates the basis of the technology. GPS satellites Camera Enforcement Classification $ Smart Card In-Vehicle Unit (IVU) Wireless communication link Back office system Portable/mobile Figure 1: Principles of VPS EFC (from Hong Kong ERP study)
EXPERIENCE OF VPS-BASED EFC SYSTEMS This section briefly describes the development of the VPS approach for EFC, from the early SOCRATES projects, through the German motorway tolling trials, the establishment of the ISO/CEN standardisation sub-group on VPS, the Hong Kong ERP Feasibility Study, various smallscale trials around the world, through to the UK DIRECTS project and the Swiss and German HGV charging systems scheduled for full implementation by 2001 and 2002 respectively. In the SOCRATES (System Of Cellular RAdio for Travel Efficiency and Safety) projects, partfunded by the EU from 1989 to 1995, initial investigation took place over the potential for EFC using cellular radio in place of the DSRC link. In 1995 the German motorway tolling trials included two systems based on the concept of virtual beacons. These were based on using the GPS (Global Positioning System) satellite location system and on-board processing to determine and apply charges without the need for widespread installation of expensive gantries. In 1996 the ISO/CEN standardisation committee dealing with road transport telematics established a sub-group to propose standards for EFC based on satellite positioning and cellular communication. In 1997 the Hong Kong Government initiated a 27-month Feasibility Study on Electronic Road Pricing (ERP), to include field evaluation of two ERP technology options. The two options assessed during on- and off-street field evaluation programmes at the end of 1998 were one based on DSRC and one using GPS positioning. Because GPS had not been specified to suppliers, but rather the concept of using an on-board positioning capability, the generic term Vehicle Positioning System (VPS) was coined for the evaluation programme. During 1997 and 1998 the Swiss Government developed specifications for the system which is planned to be introduced in 2001 for charging Heavy Goods Vehicles for road usage. These include the use of GPS positioning to provide additional input to the on-board equipment. Two systems are currently undergoing field trials. At the end of 1998, the UK Government issued an initial call for expressions of interest from consortia who could supply the systems to undertake the next stage towards the implementation of road user charging in the UK, namely a major demonstration project in two sites in England and Scotland. The call indicated that systems based on VPS technology, demonstrating an end-to-end capability including enforcement and billing, would be considered. After much negotiating, the final specifications of the DIRECTS project, which will take place in Leeds and Edinburgh, were issued in 2000, and submissions from consortia wishing to supply the system are under consdieration at the time of writing. Also at the end of 1998, the European Commission issued a communication on interoperable EFC systems, including recommendations for actions to be taken to achieve progress towards interoperability. The communication recognises that there are two technological approaches to EFC, DSRC and VPS. After several years of follow-up work from the 1995 trials, the German Government has this year issued functional specifications for a charging system for HGV which is to be operational on the complete autobahn network during 2002. It is likely that VPS systems will be particularly attractive to consortia bidding for this system, because of the very high costs of roadside
infrastructure if the system were to be implemented using DSRC. This major project is likely to have a particularly strong influence on the future development of EFC based on VPS. The city of Copenhagen has undertaken various trials of VPS technology. Both Copenhagen and Gothenburg are part of the European 'PROGRESS' project which started in May 2000, and both these cities are committed to implementing trial VPS charging systems as part of the PROGRESS trials and demonstrations of urban road user charging. Both Australia and New Zealand are actively investigating schemes for charging heavy vehicles for road usage based on their actual usage, which could be based on electronic systems using VPS technology. THE INITIATIVE PROJECT INITIATIVE (INdustry Initiative To Introduce Automatic Tolling In Vehicles in Europe) is a tightlyfocused project with the specific objective of validating aspects of interoperability between free flow, multi-lane EFC systems based on DSRC and those based on VPS. The project, part-funded by the European Commission, specifically addresses issues relating to the use of different technologies for EFC systems as called upon in the EU Council Resolution 97/C 194/03. This is in recognition of the fact that although DSRC systems might be regarded as nearing maturity for possible road user charging applications, the virtual gantry approach offered by the use of autonomous in-vehicle equipment might offer a more attractive alternative in the medium term. The main aspect of interoperability to be validated in INITIATIVE is the use of common integrated On-Board Equipment (OBE) including an interface which will function with a DSRC system and a VPS system. This will enable field trials to take place in which a vehicle is able to operate, using the same equipment, in areas with DSRC and VPS-based EFC systems. During 2000/2001, test sites are being implemented in Germany, Switzerland and the UK and a series of field trials will take place when the systems are operational. STANDARDISATION In 1996, the CEN Technical Committee (TC278) responsible for road transport telematics established a sub-group specifically to work on an application data interface standard for EFC systems based on satellite positioning. In 1997 the subgroup published an Internal Technical Report (ITR) describing the scope of the proposed standard. During 1998 it was agreed that responsibility for the work of the GNSS sub-group, 1.5, should pass to ISO rather than CEN, because of the level of interest in the approach from outside Europe. It is planned that a draft of the application interface definition pre-standard should be available during 2000.
ADVANTAGES AND DISADVANTAGES OF DSRC AND VPS-BASED EFC, AND PROSPECTS FOR IMPLEMENTATION Without doubt, DSRC is widely accepted as the primary technology available for EFC systems. Moreover, in most parts of the world it is expected that any new EFC system will be based on DSRC technology. However, the recent experiences described in this paper have led to an increasing awareness of the potential of VPS-based systems as an alternative to DSRC in certain circumstances. The main attraction of using VPS is in the fact that charging is effected without the need for roadside infrastructure at charge points. Gantries are expensive and, especially in an urban environment, can have a high level of environmental intrusion. In many town centres, for example, it would be almost unthinkable to erect substantial structures in order to implement road user charging. In addition, the density of existing underground utilities along the roadways in many cities makes it difficult or impossible to erect gantries in what would otherwise be suitable locations. Because the charging is effected at virtual gantries, VPS-based systems also potentially offer much more flexibility in defining, or refining, charging systems. It is likely that in any road user charging system the scope of the system would need to be reviewed regularly and to be modified in the light of, for example, road network changes or significant land use changes. An example is Singapore, the site of the only fully operational urban ERP system in the world, where the original Area Licensing Scheme has been amended and extended several times. Using VPS such changes could be readily implemented without any need for on-street alterations. The main disadvantage of the VPS-based approach is the higher cost of the in-vehicle equipment. However, component costs are rapidly falling, and it is likely that in a realistic timescale in which to envisage the possible introduction of VPS-based EFC systems, the unit cost of the in-vehicle equipment would not be much more than the equivalent DSRC-based unit. Although VPS-based invehicle costs are likely to remain higher than the equivalent DSRC equipment, full system costs may be comparable because of the smaller infrastructure cost using VPS. VPS offers the opportunity of integrating a range of ITS applications in one in-vehicle platform. As the implementation of such systems becomes more widespread and, in parallel, the opportunities for implementing innovative transport polices using road user charging increase, it is likely that the VPS approach for electronic fee collection will become the accepted approach for the twenty-first century. erp1110 paper on VPS for Turin World Congress.doc