If you read the blog post and the full report (PDF), you'll discover that a quarter of all bridges are "structurally deficient or functionally obsolete." Functionally obsolete means "inadequate for today's traffic." Oh.
To give you a sense of the difference, the Throgs Neck Bridge is structurally deficient. Large trucks are only allowed to cross at night when there's very little other traffic, because in 2005 the bridge engineers discovered big cracks in the concrete. By contrast, the Whitestone Bridge is only functionally obsolete: it has relatively narrow lanes and can't carry as much weight as the State DOT thinks it should, but otherwise it's in good shape. In neither case are we talking about something like the I-35W Bridge in Minneapolis.
Apparently, though, in the minds of congressional staffers, "a lot of people want to drive over them (usually for free) and that means that sometimes they have to slow down" is exactly equivalent to OMG THE BRIDGE IS FALLING DOWN EVERYBODY PANIC!!!" In this mindset, both are equally deserving of funding, and the fact that together they make up a quarter of the total means that Something Must Be Done. Forget about transit, about unemployment, about global warming, the bridges are going to fall down and we need to spend money now!
If you look at the actual data that went into the report, it's the last line on this table. Out of 603,245 bridges, 71,179 are Structurally Deficient (12%, which is more like one in eight than "one in FOUR") and 78,468 are Functionally Obsolete (13%) for a total of 149,647. The Federal Highway Administration thoughtfully provides area totals as well, so that we can see that the Structurally Deficient bridges only comprise 9% of the total surface area of the country's bridges.
Turns out I'm not the only one who's jaded by this annual "infrastructure madness." Jack Shafer wrote about it last year for Slate. The entire post is worth reading, but my favorite quote is this one:
So credulous is press coverage that reporters almost never ask whether some Rust Belt bridges might be redundant or economically superfluous because industry and population have moved on. And just because a bridge occupied a place on the traffic grid once shouldn't give it a right to eternal service.
I would add that somehow every time a bridge is slated for rehabilitation or rebuilding, it always seems to wind up with a few extra lanes tacked on. So there's actually a triple bait-and-switch going on: you're willing to spend money to prevent heavily used bridges from collapse, but you wind up spending a lot more to (1) add lanes to (2) relatively unimportant bridges that are (3) not in any danger of collapse.
We kind of expect credulous reporting from mainstream outlets like the Star-Tribune. But how about some healthy skepticism from public radio reporters like Andrea Bernstein? Or transit advocates like Veronica Vanterpool? We're counting on you, guys. Don't get taken in.