Egan: Double-decker buses did poorly in 2007 winter road test, Manconi says they were upgraded and are safe
KELLY EGAN
Updated: January 17, 2019
A first-generation OC Transpo double-decker performed so poorly during winter testing in 2007 that the driver felt it was unsafe to even continue.
The surprising conclusion is buried in an 189-page report done by the National Research Council as the city was evaluating the fitness of the U.K.-made buses in cold climates. Over time, OC Transpo would buy 133 of the $1-million buses, now the subject of close scrutiny after a second disastrous crash last week.
“This bus has not yet been deployed into a North American winter climate area such as Ottawa, therefore it was of interest to evaluate its winter performance,” the introduction reads.
The Enviro 500, made by Alexander Dennis Ltd., was sent to a well-known test track in Blainville, Que., and outfitted with sandbags to simulate a real passenger load.
Among the standard tests in the bus industry is one called “double-lane change” in which the bus is required to start in the right-hand lane, move smartly to the left and, about 35 metres later, move back into the right lane. (Imagine passing a car, then returning to the curb lane.) The test was done 26 times at different speeds, with pylons marking the lanes, on a snow-covered track with patches of ice beneath.
The faster the bus moved, the worse the results were. At 35 kilometres an hour, the bus made five clean runs on the double-lane track, with no issues. At 40 km/h, the bus only had two clean runs out of five, striking one cone on the other three attempts.
When the test speed was bumped to 50 km/h, things began to fall apart on that January day, when the temperature was -20 C. The bus entered the course at 47 km/h, the report says.
“New track; over steered when entered into the course,” the comment section reads. “The driver said it was not safe at this speed; hit cones, broke the steering wheel sensor, had to go wide on exit to recover.”
Later on the same page, the authors write: “The driver was able to bring the bus to a stop safely. However, he expressed his concern about attempting another manoeuvre at the same speed and it was decided that no other tests would be performed.”
OC Transpo general manager John Manconi stressed that the current buses are safe vehicles in winter.
He said NRC recommended in 2007 that rear-traction assist systems and electronic braking be added as options to the vehicles and that OC Transpo has always added those features in bulk buys in 2012, 2015 and 2017.
“We’ve gone the extra mile. I don’t want the community to panic over this stuff.”
The NRC said those added features would be a “significant improvement” on slippery surfaces.
There is no mention in the NRC report that speed limits on the Transitway vary from 50 km/h through the 50-plus stations to as high as 90 km/h in straight, clear stretches.
But the testers did issue a warning.
“Based on test results, a bus driver should have no difficulties in executing a double lane change on a similar surface, when the entrance speed is less than 46 km/h. This is below the 60 km/h speed limit of a typical urban arterial road and well below the 100 km/h speed limit of the Queensway.
“It is unlikely that a driver would be able to make a successful double lane change evasive manoeuvre in conditions similar to those of these tests at the prevailing speeds on these highways. This manoeuvre would be even more difficult if the temperatures had been around freezing, when the snow and ice would have been much more slippery.” [...]
