Associated links (R15V0191)
Peter Hickli
Investigator-in-Charge, Transportation Safety Board of Canada
and
Sarah Harris
Human Factors Investigator, Transportation Safety Board of Canada
Vancouver, British Columbia, 13 July 2017
Check against delivery.
Peter Hickli
Good morning.
On the morning of 11 September 2015, a CN train struck an ambulance at a crossing in Langley, British Columbia. The two paramedics inside, including one who was driving, were injured. A patient who was being transported in the back of the ambulance later succumbed to injuries sustained in the accident.
The TSB's investigation revealed that the initial question of "what happened" was relatively straightforward: the ambulance entered an intersection with an active grade crossing warning system (GCWS); the driver, whose cell phone was active at the time, attempted to make a left-hand turn but stopped on the tracks when a lowered crossing gate for the opposite lane appeared to block forward progress. The ambulance was subsequently struck by a northbound train travelling at 34 miles per hour.
But in order for the TSB to properly fulfill its mandate of advancing transportation safety, "what happened" is just the start. We also need to ask "why." For instance, why was the driver's cell phone active? Why did the driver enter the crossing with the warning signals flashing? And why did the ambulance stop foul of the main track?
The answers led us to examine issues such as:
- the complexity of the crossing;
- driver distraction;
- situational awareness and information processing; and
- the cognitive workload involved with left-hand turns.
Sarah Harris, one of the TSB's human-factors investigators, will now explain some of what we found.
Sarah Harris
Thank you, Peter.
Accidents are almost never caused by one single factor, and this one was no exception. The TSB's investigation revealed that:
Although the distraction of the cellphone likely decreased the driver's ability to detect the warning signals, the complex design of the crossing also contributed to the accident, with multiple lanes, two distinct rail tracks close together, and many different visual cues—some of them harder to see or appearing to be contradictory. One possibility, for instance, is that the red flashing railway-crossing lights on the right-hand side of Crush Crescent may have been momentarily obscured by a crossing sign. All of these put together limited the driver's "situational awareness"—that is, the ability to perceive and process the relevant information in the environment. Further, any assessment that it was safe to proceed, could have been reinforced by green traffic lights at the intersection ahead. These lights are designed to sometimes stay briefly green despite an approaching train, in order to "flush" any remaining traffic from the intersection. Add to this the faded roadway markings, specifically, the left-turn lane, which likely helped bring the ambulance in close proximity to the westbound gate arm and led to the driver's perception that the way forward was blocked, even when it wasn't.
Peter Hickli
Since the accident, a number of steps have been taken to improve this crossing, by making the interaction between drivers and their environment as unambiguous as possible:
- The grade crossing warning system (flashing lights and gate) that controls eastbound traffic has been relocated to encompass both tracks
- The equipment that controls the active warning system has been upgraded, and the warning time has been extended.
- Flashing lights have been installed overhead for better visibility, some pavement markings have been repainted, and an LED sign warning of an approaching train has been added.
Technology has done much to make the interactions of road vehicles and trains safer. It can also do more. But drivers too must do their part. Better warning signs, clearer signals and improved sightlines may still be insufficient if drivers are distracted and do not pay enough attention to the environment around them. This accident provides a tragic reminder of exactly that.
Thank you.