Ottawa bus crash both 'horrific' and 'unique,' inquest jury hears

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The Westboro bus crash was so unique a collision that no amount of structural reinforcement on the double-decker could have prevented its tragic consequences, a crashworthiness expert testified Tuesday.

Suzanne Tylko, Transport Canada’s chief of crashworthiness research, prepared a report on the “mechanism of injury” in the Westboro bus crash.

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In that report, Tylko concluded the Jan. 11, 2109, incident that killed three passengers and seriously wounded 17 others was “different from all other documented collisions.”

“It is very unique,” Tylko told inquest jurors. “It’s a very challenging type of collision because, in this case, the bus struck a rigid structure. Typically, when we have collisions, it’s the bus striking another vehicle or maybe striking a roadside structure.”

Striking something flat or collapsible can dissipate the energy of a crash, Tylko said, and allows the frame and structure of a bus to absorb some of it. Striking a narrow object concentrates the energy, she said.

Ill-fated OC Transpo Bus 8155 struck a narrow, rigid structure — the passenger shelter awning at Westboro Station — aligned with the top portion of the double-decker. It penetrated seven rows deep on the passenger side of the second deck and collapsed nine rows of seats.

The C-shaped station canopy had two leading edges: one lower and one higher. The structure did not bend or crumple in the crash.

Unfortunately, Tylko said, the canopy also struck “the soft spot of the vehicle,” just above the floor of the upper deck, a more structurally robust part of the bus.

“This was a horrific accident,” Tylko told the inquest, “and, as this canopy was penetrating inside the bus, it was picking up the seats with it and pushing them back. All of these seats and the passengers were being pushed back behind that canopy.”

Those killed — Bruce Thomlinson, 56, Judy Booth, 57, and Anja Van Beek, 65 — were seated in the first, third and fifth rows in window seats on the passenger side.

The inquest has heard the bus was travelling between 36 km/h and 40 km/h when it struck the shelter.

“The canopy penetrated nine rows, so we can argue about the exact speed at which the bus struck the canopy,” Tylko told the inquest, “but the fact that the canopy made its way all the way to the ninth row is indicative of the tremendous amount of energy that was applied to that area of the bus.”

Tylko said there was no way to engineer a bus to protect passengers against such a hazard; she suggested the best way to protect them would be to avoid hitting the structure.

The inquest has heard that OC Transpo driver Aissatou Diallo was six months into her career when she lost control of Bus 8155 on what was a cold, clear afternoon.

The double-decker drifted onto the shoulder of the Transitway, hit a snowbank, a rock wall and another snowbank before slamming into Westboro Station’s bus shelter.

During Diallo’s criminal trial in 2021, court heard that some orange construction lines, exposed after being covered with black paint, may have confused the driver as she approached the station. Diallo’s defence team suggested those lines led her to steer the bus onto the snow-bound shoulder as she drove west into the setting sun.

A City of Ottawa engineer told the inquiry Tuesday that the lines were painted on the Transitway during repairs of a utility bridge, 90 metres east of Westboro Station, between July and November 2018.

The lines were painted to direct buses around scaffolding set up during the project.

Bin Wang, the city’s senior engineer of infrastructure projects, said the construction contract stipulated the orange lines were to removed “mechanically,” either through sandblasting or asphalt grinding. It’s a standard clause in any contract where lines are painted on roads, he said.

When the project ended in late November 2018, the contractor covered the orange lines on the Transitway with black paint.

The city did not inspect the site, Wang said, since it had hired an engineering firm, Parsons Corporation, to do that job. Parsons did not report the existence of the painted lines to the city.

Wang said he did not find out about the contract deficiency until eight days after the Westboro bus crash. At that time, he said, the orange lines were “clearly visible” on the Transitway.

The markings were not permanently removed until June 2020, 17 months after the Westboro bus crash.

Wang said he believed the additional delay was due to the crash investigation and the difficulty of gaining access to the site from OC Transpo.

When asked by coroner Dr. Louise McNaughton Filion if there should be a city safety audit following a street construction project, Wang agreed. “I think that’s something we can consider for future contracts, given what we’ve learned from this,” he said.

Andrew Duffy is a National Newspaper Award-winning reporter and long-form feature writer based in Ottawa. To support his work, including exclusive content for subscribers only, sign up here: ottawacitizen.com/subscribe