You've heard of road-race runners "hitting the wall," but if you participated in yesterday's Vancouver Sun Run, you were probably at greater risk of a "bump on the road."

That's because at the finish line, a literal bump in the road saw many runners trip, fall and sustain injuries at the end of their 10 kilometres.

It was grey — the colour of the pavement — slightly raised, and ran the width of the race area.

Sun Runners tend to one of their own after an injury at the finish line. (Stephen Quinn/CBC)

Race director Tim Hopkins says the bump was part of the announcer's information system that feeds information about the racers passing over it to the announcer.

"It's a worldwide-used timing system. It's recognized by multiple running groups," Hopkins told On The Coast host Stephen Quinn.

"I think, unfortunately, people were just caught up in the emotion of finishing 10K, and unfortunately weren't looking at the ground."

Hopkins says his medical reports showed six people needed to be treated for tripping at the finish line, but Quinn disputed that number, saying he saw "dozens" fall when he watched the race at the finish line.

"People might have gone down and not asked for treatment or reported treatment," Hopkins said.

He also says there was nothing organizers could have done about the grey colour of the bump, because it was provided by an outside supplier.

Removed, but returned

Hopkins says volunteers removed the system for a time, but it was quickly returned to its position. Volunteers were later posted to the bump to warn runners of the obstacle, but Quinn questioned why it took hours, in his estimation, for anyone to be posted to it.

Hopkins surmised it might have come down to insufficient communication.

"A volunteer that has been put out there has been communicated a role, and the role that they are out there to do often has not given them enough information to make a decision. They have to report it to whoever's in charge of their area, and then it has to go up the chain of command," he said.

"People can't arbitrarily make a decision to pull a system they know nothing about. … If it's an absolute decision, obviously people need to make a decision and take the right steps. I imagine that the volunteers that were in place felt that they were not able to make a recommendation. They weren't able to communicate."

Hopkins says he has not fully debriefed with everyone involved with the event and would not offer possible changes for next year's event.

With files from On The Coast

A medical volunteer tends to a woman who tripped on the finish line bump. (Stephen Quinn/CBC)

To hear the full story, click the audio labelled: Vancouver Sun Runners tripped, injured at finish line by hard-to-see hazard