UPDATED -- I expected more from the National Transportation Safety Board investigation of the Skagit Bridge collapse. Given how thorough the agency has proven itself to be in air crash investigations, it seems the Board sat this one out and contented itself with simply issuing recommendations -- a bit of arm-chair quarterbacking, as it were.

There is no excuse whatsoever for a driver striking a low bridge, or any other obstruction for that matter, if the obstruction is marked accurately. That obviously wasn't the case with the Skagit River Bridge on Interstate 5, and there's only one doorstep on which to lay that blame: the agency or department responsible for such structures -- in this case, the Washington State Department of Transportation.

Of the 26 conclusions the Board came to in the months of investigation, only two, no. 24 and 26, really relate to the state's responsibility in this matter.

They are:

  • Low-clearance signs in advance of and on bridges and tunnels provide valuable warnings to drivers of vehicles carrying overheight loads to help them avoid striking overhead obstructions.
  • Drivers of overheight vehicles would benefit from having a warning sign that indicates the proper lane of travel for their vehicles when traveling underneath an arched structure.

I'll come back to these, but in that long list of conclusions, the pilot-car operator was rebuked for talking on a hands-free cell phone at the time of the strike, which the board determined might have diminished the pilot-car driver's awareness of the situation and "which reduced her attention to her escort duties." Predictably, distracted driving gets some of the blame here. That's an easy call.

The board notes by not communicating any information about the narrow lane widths on the bridge or the reduced overhead clearance in the right lane of travel to the truck driver before they reached the bridge, the pilot/escort vehicle driver failed to fulfill the duties of a pilot-car driver.

The pilot-car driver was also taken to task for not maintaining adequate distance between her car and the truck so as to be able to provide a timely warning to the truck driver. As well, the pilot-car driver claims she was not aware that her height-pole had struck the bridge truss, despite testimony from a witness that it had. That should have been an easy one for NTSB to sort out. If it had struck the bridge there would have been marks on the pole or the bridge. NTSB says it was unable to determine if the pole had struck the bridge.

There were other conclusions and recommendations related to the pilot-car driver's responsibilities in researching the route, providing direction to the truck driver, ensuring they had proper training, etc. To me this indicates NTSB is badly out of touch as far as the realities of pilot-car operation are concerned and the movement of oversize loads generally.

Very few regulations exist related to pilot-car operation. Moreover, the ones that do exist are closer to guidelines than regulations. One top-notch pilot car operator I know has been pushing regulators in the U.S. and Canada for years to tighten things up, but to no avail. Pilot-car operators have a big responsibility when it comes to the safe movement of big loads, but practically anyone with a pickup truck, a CB radio and a broomstick can be a pilot-car. I'm not for a moment saying that was the case with this operator, but I've seen others that leave a lot to be desired.

The truck driver, too, was the focus of several NTSB conclusions and recommendations. Not surprisingly, the board believes the driver and or the carrier should have done more research in choosing the route for the load, and should have been aware of any obstructions they may have run into along the way -- pun intended.  

In defining probable cause for the collapse of the bridge, NTSB lists three causes:

(1) insufficient route planning by Mullen Trucking LP and the oversize combination vehicle driver;

(2) failure of the certified pilot/escort vehicle driver to perform required duties and to communicate potential hazards, due in part to distraction caused by cell phone use; and

(3) inadequate evaluation of oversize load permit requests and no provision of low-clearance warning signs in advance of the bridge by the Washington State Department of Transportation.

I really think the agency got those in reverse order. First and foremost, how is the trucker supposed to plan a route when insufficient data exists on the bridges? WDOT was held to account for not having low-clearance signs posted on the approaches to the bridge and for inadequate evaluation of the permit request. I think that's where the real blame stops.

If the state grants the permit and the load is in compliance with the permit, who else can you blame?

So back to my earlier two points. If a driver hits some overhead obstruction that is adequately marked, then throw the book at the driver. If the driver hits an overhead obstruction that is incorrectly marked, it becomes the fault of whoever put up the sign.

The Skagit River Bridge had no such warning signs, yet all over the country I've seen signs warning of low clearances at the extremities of an arched structure. That's a message to move into another lane. You need adequate time to react to such a warning, but they are out there and they are obviously effective most of the time.

As a testament to their effectiveness, I can recall when New York State used to post overhead clearances using what it called "curb height". That was generally about a foot lower than the actual overhead clearance. You could always tell when a bridge had a questionable sign by all the skid marks on the road approaching the bridge. Those signs get truckers' attention.   

The NTSB lists 18 recommendations in its report on the Skagit River Bridge collapse, and I'm sure if they had more time they could have come up with more. But there are really only three that if implemented would have prevented this incident: Better over-height clearance data on bridge structures; better ways of making that information available to carriers requesting permits; and warning signs on the bridge approach.

As I understand it, prior to the incident the Skagit River Bridge appeared on state registries showing its actual clearance at the tallest part of the structure. The clearance under the arched portions isn't mentioned. So a carrier, driver or pilot-car operator researching a route would have seen adequate clearance under this bridge for the load being hauled. The State DOT obviously did too, as it granted the permit. No red flags went up alerting anyone to the arch, or warning them to use the center lane, for example.

I can't see any other way than to hold the state about 80% responsible for this, but determining responsibility isn't NTSB's mandate. The agency makes recommendations that will prevent similar occurrances in the future. So the way I read the board's recommendations, I think it would be completely reasonable for every over-height load to stop at every bridge it came to and measure it before proceeding under it. How else could you utterly sure the state's information and your permit are accurate?

Read the Seattle Times story that carries the WDOT's comments to the NSTB report.

Update adds initial comments from Washington State Department of Tansportation.

About the author
Jim Park

Jim Park

Equipment Editor

A truck driver and owner-operator for 20 years before becoming a trucking journalist, Jim Park maintains his commercial driver’s license and brings a real-world perspective to Test Drives, as well as to features about equipment spec’ing and trends, maintenance and drivers. His On the Spot videos bring a new dimension to his trucking reporting. And he's the primary host of the HDT Talks Trucking videocast/podcast.

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