National interoperability SECOND THOUGHTS

October 7, 2012

2012-10-07: In our earlier report of the IBTTA/E-ZPass Group (EZPG) 'webinar' we suggested a conflict in approach between the Alliance for Toll Interoperability (ATI) and the EZPG which is probably more a difference in emphasis and healthy competition in approaches. ATI's hubs happen to have been used so far to clear transactions between tollers that mostly originated in license plate imaging, but they are a back office transactions clearing network, and can process any kinds of transactions.

The E-ZPass Group wants to emphasize high levels of performance in transponder-reader transactions and their focus for now is on how to do interoperability at the front end.

This is more a difference in emphasis or focus rather a conflict. For the foreseeable future - certainly within the 4 year MAP21 timeframe for interoperability - there will be vehicles without transponders, so whether you like it or not there will have to be cameras and an effort to clear interstate transactions from camera imaging and license plate reads.

Solutions are needed in both areas. The ATI is also focussed on a different method of back office clearing of transactions between different tollers.

The ATI hubs are an alternative the EZPG's peer-to-peer clearing of transactions but the two can well coexist. They do already. The E-ZPass Group itself while mainly peer-to-peer has small hubs within it - Virginia for example.

ATI's hubs while used so far for clearing camera-derived transactions can clear any kind of transactions, regardless of the front-end and whether it originated with a transponder reader or a camera. A major advance pioneered by ATI is having the hub operator deal with different business rules and file formats, whereas the E-ZPass Group has stressed the importance of harmonizing business rules and file formats first to simplify interoperability.

They are competitive approaches but not incompatible. Both will probably be needed. The differences are ones of degree.

The E-ZPass Group still has many different business rules toller to toller. Harmonization of business rules makes transaction clearing simpler and cheaper but software can be written to handle differences. They did it for the pilot hubs.

ATI and the EZPG also have a different approach to staging or sequence for interoperability. The ATI's hubs have reflected the approach of let's-do-it and solve problems and deal with incompatibilities while doing it, whereas the EZPG emphasis has been more on ironing out differences and advancing harmonization before doing interoperability.

The great virtue of the MAP21 legal 4-year deadline for national interoperability is that it is going to force the issue. If the EZPG had its way it would - as with procurements - plan, and study, and test, review sample coverage, study some more, and retest. . . to, what, about the year 2025?

earlier report:


E-ZPass Group's materials on how it does interoperability internally:

TOLLROADSnews 2012-10-07

Further Reading

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