RAND VMT report lead author responds to criticism, says did not reject RFID

Paul Sorensen, lead author of the NCHRP-RAND-AASHTO report on nearterm technologies for vehicle miles traveled (VMT) charges has responded to criticism, claiming the group does not dismiss the utility of RFID. In a posting to the congestion pricing weblist "con-pric" he says the report authors considered equipping vehicles with RFID transponders and mounting readers through the most heavily trafficked parts of the highway network. This was considered "a reasonable and attractive option," he writes in contradiction of what the report itself states.

However the authors were steered away from this by the NHCRP project panel: "they asked us to only focus on mechanisms that could capture all VMT."

Since the NCHRP project panel overseeing the study wanted road use charges collected even on tiny local roads the study group was driven to discard low cost RFID transponders and to embrace  expensive on board units (OBUs) that need connections to the engine diagnostics, GPS, and cell phone technologies, Sorensen says.  

RFID "a valuable role"

Sorensen now concedes that RFID has a major role to play:

"Even if not used to try to capture a large share of VMT through the road network via communications with mounted readers, RFID could still play a valuable role in all of the mechanisms that we did recommend as most promising for near-term implementation. In the case of estimated mileage based on fuel economy and fuel consumption paid at the pump, vehicles would be equipped with RFID/AVI devices to communicate make/model information to readers at the pump to facilitate mileage estimates."

He says in two of the three methodologies recommended for further study vehicles "could be equipped with RFID." Could be!

This would allow for heavily traveled routes to be "equipped with gantry-mounted readers to allow for congestion tolls on top of the base mileage charges."

Presumably regular tolls could also be collected by toll agency readers using these same transponders.

Sorensen explains the deficiencies of the report - which has attracted some trenchant criticism - by saying it was an extremely fast study, just three months from kickoff to delivery of the final draft. He says they couldn't find data that would have allowed them to cost the various options.

(We called it the report "unprofessional" for dismissing RFID as involving "considerable expense" and then choosing three methodologies requiring far more expensive OBUs without any attempt at comparing costs - editor)

Sorensen says that while there are arguments for implementing or experimenting with VMT charges at a state or lower level the "charge" given to the authors was "to focus on national level implementation."

On the report's focus on fulfilling lobby group AASHTO's efforts to shore up the status quo policy of national tax and grant Sorensen writes: "The project was managed by TRB under an NCHRP series that is funded by AASHTO. In the spirit of promoting greater rigor and objectivity, RAND requested that TRB subject the report to external review, and TRB granted this request."
 
The RAND report recommended future development effort be focussed on three alternatives:

(1) mileage estimates based on nominal miles per gallon and fuel consumption

(2) mileage estimates based on an on-board device drawing data from the engine diagnostics port (OBD2) and cellular wireless location, and

(3) mileage estimates based on an on-board device featuring coarse resolution GPS

Sorensen uses the term "metering" in (2) and (3) rather than estimates, using a verb that implies high accuracy.

For (1) fee collection would occur at the fuel pump, for (2) and (3) collection could occur at the pump (as in the Oregon trials) or by wireless transmission of billing data to a central billing authority, as in Seattle and Iowa trials and the German TollCollect.
 
Work on uncertainties and costs

Sorensen writes: "It is important to note, however, that the report also suggested that there are several remaining uncertainties, particularly with respect to cost at scale, that make it difficult to choose the best option now. As a result, the report recommended a series of activities that could be funded in the upcoming reauthorization, including targeted research and trials, that would make it possible to identify with greater confidence the most cost-effective metering and collections options and pursue implementation beginning in 2015."
 
Sorensen writes that rather than mandating a particular technical configuration for the on board units the national system could instead "identify and codify a set of standards" that various system components should meet.

Different private vendors could then compete to supply the equipment on the basis of added functionality as well as price. Confining the specification to standards would allow for future technical innovation and help drive down prices.

"A key benefit of VMT fees is that they remove the issue of improved fuel economy (and, for that matter, fuel type) from the equation. Should, as expected, the coming decades witness significant improvements in fuel economy in conventional vehicles as well as greater penetration of alternative fuel vehicles, VMT fees will remain much more stable than fuel tax revenues. They would still need to be raised to account for inflation, but the raises would not need to be as large or as frequent."
 
Sorensen says that provided that the metering technology offers sufficient flexibility, the per-mile fees could be structured to vary with certain vehicle or travel characteristics to address other transportation policy issues such as varying charges by vehicle type, place and time of day - congestion pricing.

He does not explain however how this could be done with distance estimation based on fuel consumption and fuel mileage or how the cell phone and coarse grained GPS units could be made accurate enough for differential pricing between toll lanes and free lanes or indeed define congestion priced zones with consistency and clarity.

He says mileage estimates based on fuel economy and fuel consumption offers "relatively low metering flexibility at comparatively low cost (minimal per-vehicle equipment cost) while the two options involving on-board metering equipment, in contrast, offer greater flexibility at greater cost."
 
Sorensen says that for tolling trucks with GPS high resolution GPS is needed. He fails to acknowledge this means German style OBUs costing about $500 each, ten to twenty times the cost of 5.9GHz Omniair style transponders. And he calls mileage estimates from fuel consumption minimal cost without highlighting the minimal accuracy provided.
 
"For general traffic, we judged the ability to determine specific route of travel to be somewhat less important, for two reasons. First, even with coarse resolution GPS one could still implement area-based congestion tolls (e.g., higher per-mile charges within a particular zone during peak travel hours). Second, if the decision were made to implement facility-based congestion tolls in certain locations, one could install gantries along those facilities to communicate with the on-board equipment in passing vehicles to levy such tolls."
 
He justifies the use of coarse resolution GPS for general road use charges with the point that it can always be supplemented by RFID transponders and readers in those areas where facility-specific tolling or pricing is needed.

So RFID is, after all, a vital road pricing technology!

You'd never have guessed that from the report.

COMMENT: Sorensen makes a valiant effort to defend an ill-designed, and unprofessional report with a mix of "we wuz ordered" buckpassing, "we didn't have time" on costing, and some welcome backtracking on the central issue of its rejection of the role of RFID.

He still doesn't explain how a panel studying future electronic toll collection methodologies did not manage to recruit a single member with some expertise and experience in electronic toll collection, or why there was not even a sketch level outline quantifying costs and benefits of the various methodologies recommended versus those discarded.

At least he now seems prepared to acknowledge the role for RFID even as the report airily dismissed it in a few sentences.

But we are left with a confused and now qualified hodge-podge of recommendations for funding of more research and studies - editor.

TOLLROADSnews 2009-10-21