A few weeks back McGinn held a press conference where he asserted that WSDOT’s tolling figure are inflated. He released this folio.
I did a little more research and dug up a 2002 tolling study as well as 2008 draft study. Both studies were done by Parson Brinkerhoff (See Publicola’s article). The 2002 study estimated that the optimal toll rate (i.e., toll rate that minimizes system delays) could cover between $35-$95 million (2009 dollars) in construction costs. This study showed that on average drivers would pay 31 cents during peak periods, and 16 cents during off-peak periods (2009 dollar).
The 2008 draft study, which was released several weeks after the announcement of the deep-bore tunnel, however, estimate that tolling could support roughly $330 million (2009 dollars). Toll rates were set at a predetermined level to maximize revenue, with peak rates at $1.50 to $2.25 and off-peak rates at $1.10 to $1.25 (2007 dollars).
The 2008 results represents an approximate 4- to 10-fold increase over the 2002 study.
This shows that WSDOT is significantly “over pricing” the tunnel in order to generate the revenue it requires for the deep-bore tunnel. However the additional revenue comes with a significant side-effect, diversion. The high toll rates will cause an estimated 40% of traffic that would otherwise use the tunnel to divert to other routes such as Alaskan Way, downtown streets and I-5. In very rough figures the viaduct carries around 100,000 cars a day, so that works out to roughly 40,000 diverted cars a day. That’s nothing to cough at.
This is yet more evidence that the impacts of the tunnel have been poorly vetted due to WSDOT’s expedited and politically motivated choice of the tunnel.
UPDATE: I want clarify the take away of this post. I’m not disputing the tolling model, rather I’m arguing that the models themselves show that tolls will be significantly higher than what the optimal toll should be. The 2002 study describes the toll rate methodology as;
Assuming that users have perfect information about pricing, that toll revenues are used to make cost-beneficial highway investments, and that pricing is ubiquitous, then short-run marginal cost toll pricing allows the road network to operate with maximum net social benefits from the resources used to build and operate roads. In this case, the economically efficient toll rate maximizes travel time savings, which for a given volume of traffic, minimizes total network travel time.
This means that using the toll rates from 2008 will significantly change travel patters, destabilizing the system, and resulting in increased delay on city streets and I-5 while not fully utilizing tunnel capacity.