[__derek__]

> I've never seen a toll bridge that had tolls in both directions.

Huh, I think I've only seen this once (the Tacoma Narrows Bridge). Other toll bridges I've driven have all had tolls in each direction, e.g., Ambassador and Blue Water Bridges to Canada, Lake Washington floating bridge. Maybe I need to start taking more bridges to nowhere!

[dymk]

The floating bridge has a toll in both directions because there’s an alternate route which isn’t too much worse when there’s no traffic (and something about federal highway grant money)

[jedberg]

Interesting! I'll admit my sample size is limited to bridges in California, but at least in the Bay Area all the bridges only have tolls in one direction.

[dragonwriter]

I suspect the Bay Area model is more common where the dominant traffic on a bridge is two-way commute traffic that can’t easily escape the toll regime for one side of the commute. In that case, one-way tolls reduce infrastructure and operating costs, and traffic impacts, of toll collection without any significant downside.

[duskwuff]

The other half of that is a practical matter -- collecting tolls in both directions means constructing and staffing a larger and more complex toll plaza. It's hard to justify that expense unless a lot of tolls will go uncollected without it.

[dragonwriter]

> The other half of that is a practical matter -- collecting tolls in both directions means constructing and staffing a larger and more complex toll plaza

That’s part of what I waa getting at with “infrastructure cost”, yes.

[__derek__]

That makes sense. It fits with the Tacoma Narrows Bridge, which connects Tacoma (urban economic hub) to the Olympic Peninsula (some small towns, mostly wilderness).