The permit ran to several pages, and most of it was about avoidance.
Go around this bridge. Around that one. Six structures on the same highway, each one flagged, each one with a detour drawn around it.
One bridge was not on that list.
The paperwork sent the trailer straight beneath it, and the load stood 16 feet 11 inches, one inch under the ceiling the state had already approved.
It hit anyway.
Why a load inside the limit still takes out a girder
An oversize permit is not a measurement.
It is a lookup. Somebody enters a height, software checks that against a stored table of clearances, and a route falls out the other end.
Nobody walks out and lays a tape on the steel.
So the table is the system, and a figure in it that runs six inches generous makes every permit written against it six inches generous too.
The driver cannot audit any of that.
He carries a route he did not draw and a clearance number he did not take, sitting under a trailer whose roofline he has no way to check from the seat.
What the road looks like at that interchange
The overpass crosses a highway carrying about 57,000 vehicles on an ordinary day.
It is also the only road link between Anchorage and the valley to the north, which means nothing that happens there stays local for long.
There is no back way around.
When the first strike closed the southbound lanes, traffic was pushed off at the north exit, through the middle of a small town and back on again further down.
Commutes under an hour turned into five.
The approach is a long straight grade with the deck sitting square across it, and from a cab windshield that opening reads as plenty of room.
The driver had hauled oversize before.
He came up at roughly 45 miles an hour, eased off to about 25 as the span filled the glass, and went under at a crawl by highway standards.
Two strikes, four years apart
On September 28, 2022, a semi carrying modules bound for the North Slope clipped the northbound side of the overpass and damaged a girder.
The permit allowed 17 feet. The load measured an inch less.
Police did not cite the driver.
Repairs were put at 500,000 dollars to a million, and the state opened an internal review of the load height and the recorded clearances.
The first strike was the ugly one.
In March 2018 a truck hauling a prefabricated camp building hit the southbound side and pulverized the concrete around a girder weighing 200,000 pounds.
Southbound lanes shut for four days and reopened just after 10 at night on the Sunday, once the ruined girder had been cut out and lifted away.
The top of the building sheared off on impact.
That driver was cited for failing to comply with the conditions of his permit, a non criminal ticket, and the carrier later said the load it picked up was not the load it had been expecting.
Emergency repairs came in at 1.8 million dollars. The governor drove out to look at the wreckage himself.
The number nobody has published
Then comes the detail that reframes both crashes.
After the 2018 strike, bridge engineers went back and measured the southbound clearance at 17 feet 6 inches. It had been on file as 18 feet 6 inches.
A full foot of error, in the state’s own records.
After the second hit, the department marked the northbound side at 16 feet 1 inch and said outright that this is not the height of the bridge.
The sign runs deliberately low, posted to keep anything else off the steel while repairs waited.
So the real figure stays unpublished, which is how a span quietly becomes a can opener, and how a permitted oversize load can be legal and badly wrong at once.
What a remeasurement quietly admits
The response is the part worth keeping.
The state ordered an immediate check of every bridge height on that highway, so the permit division would stop writing routes off a stale file.
Read that sentence again.
A department does not send crews to remeasure an entire corridor unless it has stopped trusting the file it was writing permits from, and that is an admission.
Clearances also drift.
Resurfacing adds an inch, settlement removes one, frost works at the abutments, and a figure recorded when a span was poured can be wrong decades later with nobody at fault.
Which is the uncomfortable part of the whole thing.
The load was inside its oversize permit, the route was the one the state issued, and the bridge still came off worse.
The state timeline has the closure and the correction. The local reporting has the permit.
Read the whole thing?
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