Vice Chairman T. Bella Dinh-Zarr filed the following statement concurring in part and dissenting in part on May 24, 2016.
While I concur with the findings, recommendations, and overall report, I disagree with the probable cause. The report states that the NTSB "determines that the probable cause of the accident was the engineer's acceleration to 106 mph as he entered a curve with a 50 mph speed restriction, due to his loss of situational awareness because his attention was likely diverted to an emergency situation with another train." The lack of Positive Train Control (PTC) is listed later as a contributing factor to the probable cause. I strongly believe that PTC should be included in the main probable cause statement, along with the engineer's overspeeding.
Time and time again, in the accidents we investigate, the biggest safety challenge we find is human error, which is an area where technology can be very helpful. PTC is a safety system that uses technology to prevent overspeed derailments, among other accidents. We know that PTC is a backup system – the engineer is still in control, but we also know that PTC is a known, accepted, and implementable safety intervention that should have been in place. The NTSB has been recommending automated and positive train control systems since 1970. Since 2004 alone, the NTSB has investigated 30 PTC-preventable freight and passenger rail accidents in which 69 people died and more than 1,200 were injured – Chatsworth, Two Harbors, Red Oak, Mineral Springs, Hoboken, Westville, Chaffee, and the Bronx to name a few. In each of these accidents, the NTSB concluded that PTC would have provided critical redundancy that would have prevented the accident. But at the same time, in these accidents, we found that the lack of PTC was merely a contributing cause – rather than the main probable cause and instead placed the probable cause on the engineer's actions.
In this accident in Philadelphia last year, eight people died and many dozens have life-changing injuries because the government and industry failed to act for decades on a well-known safety hazard. So, why does our probable cause focus on one human's mistake and what he may have been distracted by? I believe after more than 40 years of recommending this proven technology and after placing this issue on our NTSB Most Wanted List for 23 of the past 26 years, it is time to take a less myopic view of the probable cause in these accidents. I understand that we try to be linear and formulaic in the way that we draft probable causes – we identify the root cause and move to the broader proximate cause. However, in doing so in every situation, we are limiting our ability to highlight the importance of prevention. We are limiting ourselves by our own institutional inertia.
We look at many different frameworks in our work and I would like to point you to Haddon's Matrix, the most widely accepted framework in injury prevention. Haddon's Matrix divides prevention into Pre-Crash, Crash, and Post-Crash. Clearly, PTC is a form of Pre-Crash prevention, which is the most effective and desirable. In addition, PTC is a well-established prevention system that we have recommended and that should have been in place on that track.
Our mission is to determine the probable cause in order to prevent accidents like this one from happening again. We always try to prevent human error, but humans will make errors and we should focus on how to mitigate the damage – in this case, preventing accidents through PTC.
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