OmniAir’s Tim McGuckin on the continuing validity of 5.9GHz-based tolling for the US.

Since its unveiling in 2004, the US Vehicle-Infrastructure Integration (VII) programme has evolved to succeed in a changing political environment. Nevertheless, there have been constants. One is 5.9GHz DSRC, the technology expressly designed to fulfill VII’s safety objectives. The second is ‘VII tolling’, the long-standing support from the US tolling industry for the adoption of DSRC technology for Electronic Toll Collection (ETC).

While it is championed as the next generation of ETC, some still question whether VII tolling is an improvement over currently deployed systems. It is clearly viable, both in terms of performance and the platform’s flexibility and scalability, but this depends on how you deploy it. In short, to reflect the saying that the best approach to an unfamiliar subject is to show a familiar face, then the more VII tolling looks like ETC, the more likely it will be accepted and deployed.

Two flavours – one goes down easier
There are two variants of VII tolling. The first is ‘VII Tactical’. This employs aftermarket tag-like DSRC units not embedded in the automobile during assembly. The OnBoard Equipment (OBE) is designed primarily for tolling (or another specific purpose) but the form factor could accommodate additional soft safety or mobility applications (vehicle-to-vehicle hard braking or accident warnings, or basic data transfer to populate traffic management systems). With VII Tactical tolling, deployment is not dependent on a national network but can scale to one.

The second type of VII tolling is ‘VII Classic’ – the original design and intent of the VII programme. Vehicles are embedded with OBEs complemented by GPS functionality and onboard computers provisioned with many more, particularly safety-critical, applications. The system is envisioned as a national network driven by the need for wide-scale interoperability: new cars must communicate no matter where they are built, shipped and driven.

The reason for the two versions stems from practical realities. VII has endured political, institutional and resource challenges that necessitate a change from the classic ‘Big Bang’ deployment approach to a tactical, staged one. For tolling, the system would feature carry-in devices that evolve as the unit’s functionality increases with the degree of embeddedness in the vehicle. What will drive this is that as applications are deployed they form a basis for later services. These innovation cycles improve the product and create a pull for the follow-on iterations.

As for the RoadSide Equipment (RSE), this will likely sit aside legacy toll systems and use their existing classification and violation enforcement equipment.

ETC versus VII tolling
As compared to current 915MHz ETC technology and processes, 5.9GHz VII tolling systems are a step-change in several compelling ways. First, they have demonstrated performance advantages: very low latency, high read distances, high data rates, and high security. Second, VII tolling is based on IEEE’s open DSRC standards and will be certified as interoperable, which should be favourable to any organisation that values a selection of competing suppliers. Third, from a business and traffic management perspective, VII systems enable more applications that advance safety and mobility – key objectives of the toll industry.

VII tolling is not a far-off vision, particularly VII Tactical, which is in the foreseeable future. Every major toll operator, developer and integrator active in the ETC market today is interested in 5.9 DSRC technology and is seeking ways to either advance it and make it viable, or delay it. Both are due to its potential to disrupt the market. VII tolling can eliminate the dependence on proprietary ETC systems.

It can end the stove-pipe approach to ITS technology deployment, as VII is designed for safety and mobility (ETC is classified as both, depending on whom you ask). There are several enterprises currently testing 5.9GHz DSRC toll systems and one that has a 5.9 product as its core offering in the US market. Those not searching for a way to be part of this movement could in fact become relics of ETC history within four to eight years.

Technical and operational challenges
As compelling as it is, VII tolling introduces new questions and demands some new best practices from the toll industry. The way these are defined and realised will impact upon how and when the business case is made to justify procurement. In some cases, existing best practices for ETC will be adapted to incorporate the new requirements of VII tolling. What matters most is what form of VII tolling is deployed. VII Tactical has significantly fewer challenges.

Vehicle classification in the VII world
In a VII system, a key challenge is interoperability of vehicle classification. At some point in time, VII toll systems will cross regions and become a national system operating with no national standards for how vehicles are classified and charged. Operators take different approaches to classifying: simple car or truck classification; axle count; length, width and height information; or a mix. Further, these classification frameworks often equate to different expressions of how a class is defined.

For VII Tactical, this would not be an issue because of the presence of the tag-like OBE: the management and distribution of it would still be in the hands of the toll industry. For VII Classic, there is a concern due to the stringent privacy policies created by the national VII Working Group. As designed, there are no permanent public identifiers broadcast from the vehicle to the tolling infrastructure that could be used for classification.

Although there may be future enhancements to the specs to allow for some type of ID (without compromising privacy), toll authorities deploying VII Tactical technology should plan that classification technologies they may use in the short term can be integrated with future VII Classic-based tolling solutions.

Existing lane configuration design
Little research has been done into the extent to which the toll industry is able to accommodate more lane configurations during a transition to VII tolling. Near-term plans to add open-road, high-occupancy and/or all-electronic lanes could be an opportunity to look at new designs that will easily support VII Tactical tolling. Existing designs will also need to co-exist with the VII Classic model as the embedded OBE vehicle population grows.

Another question is, given the fact that VII’s performance envelope is greater than current ETC systems (VII read distances are up to 3,000ft/1,000m), how will a toll operator preserve its investment in lane configuration hardware and software and support lanes which also support next-generation systems?

With existing systems and automatic vehicle identification algorithms currently tuned for read distances of only 40-60ft (25-30m), and VII systems able to detect a vehicle from 3,000ft, will the industry be able to associate 915MHz tags with the correct vehicles in a mixed toll lane stream? Or will they simply tune down the system to reflect existing lane configuration designs? How do we ensure the same gantry infrastructure can be used for next-generation DSRC tolling equipment?

Provisioning, authentication and interoperability
VII tolling will work in three ways: VII Tactical (where operators either manage OBEs and accounts or non-operators issue OBEs and manage associated accounts); and VII Classic.  For VII Tactical tolling, the process of provisioning a vehicle will not change. For VII Classic, it will be different than linking a toll tag ID with a driver’s account. Provisioning systems should thus support multiple scenarios so that existing toll tags and VII vehicles can be provisioned for the same network.

Multiple account links
VII Classic introduces the reality of application service providers who are disassociated from infrastructure providers. Drivers would use OEM-specific methods to access a range of in-vehicle VII services. This is a significant shift from today, and from VII Tactical, where the OBE is the application.

Furthermore, drivers may expect to use different accounts from within a ‘banking’ menu available in their car as they, for example, change the link from a credit card to a debit card as they approach a toll road. Switching accounts on the fly may also be wanted by the CVO community to support expense reporting. This could create back office challenges. While VII Tactical may not need to address these issues, VII Classic tolling leads to the question, “How will tolling operators guarantee that they will receive payment for services if they do not ‘own’ the account and the customer?”

There are answers, like the approach taken by Mark IV; the company is developing a 5.9GHz DSRC ‘Local Transaction Processor’, effectively a redundant reader which reads tags and permits the operator a cross-check their list of who used the facility against who the issuer says used the facility. This and settlement processes used by phone companies and the banking industry could provide answers.

Violation enforcement systems
For both VII Tactical and VII Classic models, the toll industry currently does not fully understand how Violation Enforcement Systems (VES) will operate in the 5.9GHz environment where the read zones are much extended. Existing best practices with automated plate recognition systems may continue to be relied on as VII tolling ramps up. For existing facilities, read errors associated with mixed-mode use will most likely increase as will the numbers of manual reviews required during this period.

New enforcement techniques such as those used in national road user charging projects around the world could be adopted in the US (mobile enforcement combined with other roadside enforcement techniques to sample and check vehicles). And as for toll operators in states that do not have legislation supporting VES, they need to begin to understand the technical and operational issues associated with it during any mixed-use period, if applicable, so they may help draf the appropriate operating policies.

Conclusion
Since the late 1990s, the USDOT has worked with all interested stakeholders to get the 5.9GHz band and DSRC technology developed and deployed for the safety applications of the future. ETC was recognised as a safety application. The 5.9GHz DSRC technology is being tested successfully by the auto OEMs in various locations.

Toll transactions using 5.9GHz DSRC are being tested now at live toll plazas in California and Denver, and have already been shown to work in the Detroit area VII Test Bed. The work is showing that only light infrastructure is needed to perform the equivalent of today’s transponder-based toll transactions. This says two things:
Firstly, 5.9GHz DSRC is a world-class technology that can deploy soon in tactical form and also an evolving foundation of a competitive and scalable platform lasting into the long-term. What is very clear is that many of the old assumptions of toll collection and payment systems may be turned on their heads as the industry evolves from regional applications to a national payment system.

Secondly, the transportation community, which includes operators of un-priced facilities, wants and needs to address the challenge of improving mobility. VII tolling is a great example of innovation and resourcefulness applied to this challenge. And if you believe as the author does that creativity is one of the key elements of success, then VII was founded on it and is still driven by it. Despite the uncertainty and changes of late, this is a time of anticipation and confidence. 5.9 DSRC endures and VII tolling can be the system that carries the day in the US.

DATED: 6th October 2008