In the first incident, the driver of a Mercedes SUV was able to drive off the stairs with help from onlookers.
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In the second, on Oct. 12, the driver of a Volkswagen called a tow truck, and in the most recent incident, the driver of a taxi became stuck.
Officials at UBC say they aren't sure why so many vehicles are getting stuck.
"For vehicles to get to this point they are disobeying signage preventing access and weaving through a barricade that further communicates limited access," said UBC spokesman Randy Schmidt in an emailed statement.
"However, to prevent this from happening we are looking at installing a handrail down the centre of the stairs. At this point we don’t have a time line for the installation of a handrail."
There are signs indicating the approach to the stairs is a fire lane, but there are no signs preventing cars from accessing Student Union Boulevard from East Mall, which would then give vehicles access to the wide boulevard approaching the stairs.
A Google Street-view image of the staircase shows a concrete planter was once in front of the staircase. It's unclear why that planter was removed.