On the evening of December 1 at Town Hall, speaking to a packed Stranger-sponsored forum on the downtown tunnel project, Mayor Mike McGinn appeared to stumble upon the perfect talking point. McGinn said something along the lines of "This tunnel will cost $2.8 billion but will move fewer cars than the Ballard Bridge."
Supposedly he'd used that line before to criticize the proposed replacement for the Alaskan Way Viaduct. But if he had, no one noticed. These days, that one sentence answers a question that's on everyone's mind: Does this project, as outlined in the state's latest designs and traffic estimates, actually make any sense?
McGinn's comparison to the little old Ballard Bridge cuts right through all the complication and says, in plain Seattle language, No, it doesn't.
If completed as planned, the tunnel will be almost two miles long and cost the state around $2.8 billion (the total viaduct-Âreplacement cost is $4.2 billion). But, because of its tolls and lack of downtown exits, it will carry only about 42,000 cars a day, according to the state's estimates (that's about one-third of the current viaduct capacity).
The Ballard Bridge carries more than 60,000 cars a day. According to the mayor's office, it was built in 1917 for about $500,000 (and, according to a federal government online calculator, that's about $8.5 million in inflation-adjusted dollarsâa pittance compared to the billions required to build a tunnel today).
McGinn should repeat his line about the Ballard Bridge as often as possible. He should do it to make his point, but he should also do it to draw a contrast with tunnel proponents, who have been staying relatively silent of late.
Tunnel proponents dodged questions at The Stranger's crowded tunnel forum by failing to show up at all, choosing instead to talk unfiltered to the wonks who watch the Seattle Channel the next evening and to a balanced forum slated for December 16.
It's odd. If the tunnel backers really believe they have a winning argument, then they should be willing to make their case anywhere they're invited. It is the public comment period, after all. Instead, they appear unwillingâor unableâto answer McGinn's great new question: How does a tunnel that will cost $2.8 billion and carry fewer cars than the Ballard Bridge make any sense? 
