Does GPS/GNSS-based technology provide a cost-effective means of charging or tolling on a national or international level, or are the issues pertaining to effective enforcement an obstacle. Here, leading equipment manufacturers debate the issue.
The technology choices for those looking to implement Electronic Toll Collection (ETC) have broadened considerably in recent years and no doubt this will continue into the future. A wider range of technologies equates to an increased range of opportunities in terms of operating characteristics and geographical extent. Where once only relatively limited schemes were possible (although that in itself is a relative term; 'limited' can still equate to many thousands of users), area-wide schemes on the transnational or even the transcontinental scale are now within our reach.The final choice of technology for any scheme which hopes to be successful in the long term has to be made after considering a number of factors. The extent and types of roads to be covered and the types and numbers of road users to be charged have to be balanced against the need to maximise profit by guaranteeing good levels of income and low costs of ownership over the lifetime of the system.
Dedicated Short-Range Communication (DSRC) or tag-based tolling systems working at a variety of difference frequencies have now been in service around the world for a good many years. In operation, they offer convenience of use and robustness. The cost to run such systems is typically low and the technology is well understood by road operators. Such attributes have led to tag-based systems being used by any number of tolling concessionaires around the world as well as being deployed on strategic routes in a number of countries (principally in Europe) for the purposes of charging transiting heavy goods vehicle traffic for the wear and damage it inflicts upon infrastructure.
GPS/GNSS
However, as infrastructure funding shortfalls make themselves painfully felt in some countries and the need to arrest traffic growth for environmental reasons becomes increasingly important politically, time-distance-place/Vehicle Miles Travelled (VMT) charging concepts have gained ground - at least among informed transport professionals; many politicians still fight shy of actual deployment (those in the Netherlands being an honourable exception, that country's government having stated its intention of implementing national distance-based charging for all vehicles by 2016). As a result, GPS/GNSS (satellite)-based charging and tolling systems have found themselves in the spotlight.At first sight, GPS/GNSS-based systems are the obvious choice for any 'all roads, all vehicles, all the time' charging scheme. Their principal attribute in this case is their much-reduced reliance on ground-based infrastructure. They get round the issue of having to erect large numbers of gantries - something which would be financially ruinous were every road possible to be considered.
As ever, there are balances to be struck. DSRC tags, for instance, have the advantage of being cheap to procure and easy to use. They also do not need an in-vehicle power source. By contrast, the OnBoard Units (OBUs) required for GPS/GNSS-based schemes are expensive. They have to carry considerably more intelligence and need some form of in-vehicle power to drive them. (For reference, in the Winter 2006 edition of Tollways, François Malbrunot compared the long-term costs of GPS/GSM and DSRC systems.) But perhaps the biggest sticking point for many is enforcement: a charging or tolling scheme is of little real benefit if it is so porous that large numbers of non-paying road users can expect to get away without sanction. The absence of large numbers of gantries also means the absence of a large number of ready-made opportunities to implement systems designed to catch would-be miscreants.
So where does that leave us? Does the 'wonder' technology fail to hold up in the cold light of day, or are we still left with meaningful possibilities in terms of a wide-area scheme which is able to guarantee a credible level of user compliance? Do, for instance, hybrid DSRC/satellite systems offer a solution?
Implementing enforcement
DSRC-based systems offer a relatively simple means of implementing enforcement using the existing gantries, albeit with an element of mobile enforcement being used to target foreign drivers or systematic fraud. The presumption is that GPS/GNSS-based systems will require a greater investment in mobile/portable enforcement systems with an element of proportionality, meaning that there would need to be a greater expenditure of enforcement effort on roads with higher traffic volumes. Hybrid DSRC/satellite solutions allow operators to enforce as per a DSRC-based system on those roads where tag systems are in operation but still require an appreciable level of mobile/portable systems to be in operation elsewhere.Combining technologies
Enforcement issues aside, in Europe there tends to be a more ready acceptance among equipment manufacturers of the approach of satellite-based systems."The decision over which tolling technology to use should be based primarily on a business case calculation rather than the enforcement aspects," says Michael Polt, Solution Architect with
"The exact enforcement concept depends on the tolling system as well as on the legal framework. The actual enforcement procedures depend heavily on the local legal background or on the ability to consult on legal changes wherever necessary. How to enforce and execute the penalty collection differs similarly. The collection of penalties via mobile enforcement units or by using other channels set up on local or nationwide legal defaults, such as fine settlement at vehicle registration/ registration renewal, can be viewed as standard procedures.
"The consequences for non-paying road users also vary according to the legal background. These range from blacklisting and denial of future use of the tolled road network, to vehicle shutdown until outstanding penalties are paid or even licence revocation. Without a well-elaborated legal background it will be very tough to provide efficient enforcement, independent of the background technical solution.
"Efficient enforcement requires consideration of the legal background, tolled roads/area, user group and preferred technical solution. Only then can an acceptable solution be provided.
"As the types of charging and tolling schemes increase in coming years, a variety of technologies will be used and coexist in the future - often in the same country. As a consequence, I think we can expect to see tolling solutions which are based on various technologies combining the benefits of microwave technology, satellite positioning, video and so on in a single, fully integrated solution. This approach allows using the optimal base technology for each use case while enabling interoperability so that road users need only one OBU and one account to pay for a charge in any location. Besides the existing solutions, such as fixed enforcement stations and mobile enforcement units, further concepts will be introduced which will allow efficient enforcement on rural roads or in city environments. In addition, in Europe the EETS [European Electronic Toll System] will ask for a new enforcement concept which will allow enforcement of users from other service providers as well as cross-border enforcement."
Perceived risk
For every practical purpose, the only viable way of rigging an enforcement solution is by using video cameras proving the presence of a vehicle at a certain time and location, says Steinar Furan, VP Business Development and Compliance,"Naturally, these enforcement points would have to match the locations of checkpoints or at least be defined as belonging to a specific charging zone. An enforcement system covering all vehicles through all checkpoints will require physical infrastructure to be erected on all checkpoints, rendering the whole concept of GPS/GNSS-based tolling useless if the primary purpose of that solution was to save infrastructure cost. Could one just as well have chosen to use video images and Automatic Number Plate Recogniton [ANPR] as the method of vehicle identification? The answer to this is 'it depends' because, first of all, no Road User Charging [RUC] system needs to verify the compliance of every vehicle at every checkpoint every time.
"The key here is the total risk for the user. In simple terms, if the chance of being discovered is moderate to low but the consequences of being caught are severe, or if the chance of being discovered is very high but the penalties are moderate to low, then most people will tend to comply. It is perfectly feasible to design and operate a heavy vehicle RUC scheme where the number of enforcement checkpoints is only a minute fraction of the number of charging points or zones and still maintain a high degree of user compliance.
"In some cases where a solution includes every vehicle on the road, a GPS/GNSS-based solution will be less favourable as the cost of the in-vehicle equipment becomes comparatively high. Typically, the cost of a satellite-based OBU for RUC is 15-20 times that of a DSRC OBU. For all-inclusive schemes, a good system composition could be to offer local residents travelling only on domestic roads a subscription through the national vehicle register, using ANPR to identify the vehicle, whilst vehicles from other countries and local vehicles requiring interoperable services are offered a subscription using DSRC OBUs for interoperable subscriptions. Such interoperable schemes are already operational between the three Nordic countries Denmark, Sweden and Norway, where actually three different types of DSRC system offer seamless cross-border interoperable services to any road user in any of the three countries.
"Three clear technology paths have emerged for RUC in recent years.
"DSRC OBUs in combination with video imaging to provide legal evidence and to give a secondary means of vehicle identification will remain the dominant choice for RUC because the solution offers moderate capital expenditure and typically very low operational expenditure. Q-Free systems in operation in Norway and Portugal are excellent examples of such designs.
"ANPR-based systems, where a video image is used for the purpose of identifying the subscriber and as legal evidence in cases of non-compliance, have become popular where domestic vehicles form the largest portion of traffic and the quality of the vehicle register is good. Then, the solution offers low capital and operational expenditures but the latter has a tendency to rise rapidly when the operation has to deal with foreign vehicles. The Q-Free system in operation in the City of Stockholm, where every Swedish car is liable to pay congestion tax when crossing a cordon, is an example here.
"Solutions using GPS/GNSS OBUs in combination with ANPR cameras to provide legal evidence and DSRC transponders for easy and free data read-out are gaining popularity for application within heavy vehicle charging schemes. The solution benefits from moderate capital and operational expenditures and at the same time offers the operator great flexibility with respect to tariff definitions and charging models. For countries with extensive road networks where only a small portion of the traffic is to be charged, this will be a prevailing solution in the years to come. Q-Free's system for the Slovak Republic provides an example.
"Choice of technology is always a consequence of the operation planned, the business environment, the legal basis and the availability of technical resources. All three technologies, DSRC, ANPR and GPS/GNSS, will survive and will, in different compositions and arrangements tailored to each use case, offer their services to the RUC operator for decades to come. Rather than believing in one technology making another obsolete, I believe that the unique strengths of each technology should be combined to offer better solutions to customers worldwide."
Compliance, not enforcement
According to Marc-André Funk, Director of Innovation and Research,"It disregards the fact that a well-designed tolling scheme is not dominated by enforcement efforts but by the efficiency of the detection system," he says. "Of course, it is probably easier to add enforcement functionality to RSE [gantry]-based tolling solutions as the enforcement equipment will benefit from the existing infrastructure. But objectively this reduction of costs might be small when set against the difference in system costs between RSE- and GNSS/CN [Cellular Network]-based systems, which is well-known to vary with the size and tariff structure of the tolling scheme.
"It is compliance that is important, rather than simply enforcement. Compliance with any rule may be promoted in both positive and negative manners - 'carrots' and 'sticks'. The enforcement system is exclusively concerned with the 'stick' approach, whereas the 'carrot' refers to incentives and encouragement to those who comply. There are numerous opportunities for positive incentive schemes that may be incorporated on a temporary or permanent basis to promote and encourage compliance, for example: providing discounts or 'cash-back' for continuous compliance; discounting for early or pre-payment - season tickets, for instance; and providing discounts where other modes or alternatives are unavailable.
"In addition value-added services, such as travel information or incident alerts and journey time advice, provided through a smart-client OBU, may also encourage compliance. However, these should be chosen carefully since they may work contrary to other policies, for instance route guidance versus congestion reduction. Promotion of compliance will also be achieved through the provision of public information through education and advertising programmes.
"User compliance is not simply determined by the level of enforcement and risk of being caught. A significant proportion of the population may not consider evasion if a large degree of societal acceptance is achieved. Achievement of this acceptance is likely to be influenced by many political and economic issues, including: the perceived benefit of the tax or charge to community, society or profitable venture; the scheme's perceived fairness; whether the funds collected are ring-fenced for transport investment; comparative replacement of existing taxes; benefits to the individual, such as more reliable journey times, reduced delays; and privacy and data protection." For the future, Satellic Traffic Management is already developing tolling applications that can be downloaded to a PND or cell phone, or the converged form of both.
Funk: "These will be registered with the toll operator and enforced by existing or upcoming cellular communication methods at high data privacy standards.
"The enforcement equipment will be smart and relatively 'handy' through the use of modern cameras and image processing algorithms for identifying and classifying vehicles. They will be autonomous, as they will request vehicle registrations and carry out compliance checks locally. They could be operated by standard traffic police."
Recognising the problem
In the US, there is a marked reluctance on the part of some equipment providers to comment publicly on GPS/GNSS-based solutions. This perhaps reflects differing market dynamics however"We need to start from the recognition that any tolling system can have violators. GPS/GNSS-based systems don't seem to address this in the way that DSRC does," he says.
"We see good treatment of the violation issue in the German truck tolling system - which, although it is nominally satellite-based has a good level of ground-based infrastructure - but we don't see a lot of the proponents of satellite-based tolling talk about how they'll catch those travelling without paying. You have to wonder why they don't.
"I can understand the attraction of GPS/GNSS for mileage-based charging applications but from a practical standpoint, you do need some infrastructure for enforcement.
"DSRC and video are better known technologies; we have more experience of using them. A closed DSRC system, such as Toronto's, captures everyone using the scheme. However with GPS/GNSS you can never be assured that 100 per cent of users are accounted for - if you can find some way of switching off the OBU you're effectively invisible and hybrid DSRC/satellite systems only dig into the cost advantage of a satellite-only system." GPS/GNSS solutions remain very promising, he says, but this has to be viewed in context: "The DSRC manufacturers never succeeded in getting a tag into the vehicle at the OEM level; it's all been aftermarket. I think that 5.9GHz DSRC technology still holds the most promise for the future, although one has to remain aware of such things as
"The vision is too muddied at present to allow people to make proper decisions of GPS versus 5.9GHz, because it depends on the specific choice of tolling policy."
A costly solution
To"GPS/GNSS makes sense for government-mandated tracking of heavy commercial vehicles, but how do you launch into a market such as the US with 250,000,000 vehicles when the all-in cost can approach several hundred dollars per vehicle? There are more economic ways of launching VMT over large geographic areas with a large user base.
"The enforcement technology will be derived from the business rules and what you are trying to accomplish. Does the new VMT scheme require monthly reporting? Daily? Or hourly? Each of these timeframes might point to different enforcement methodologies and significant differences in price points.
"In terms of the most appropriate technology choice, the 'ideal' is what meets the objectives of the programme at hand. Spending a dollar to chase a dime is good for academics but doesn't do much for economics. No matter what the VMT technology solution evolves to be, there will be many varied enforcement measures. And once a set of business rules are developed the industry will answer the call. Certainly any new technology developments will focus on interoperability."
