Don Borelli, a former FBI special agent who was part of the New York Joint Terrorism Task Force, said the organizers in Boston did everything right, but it's difficult to secure such a large public event.
He said co-ordination between police, fire and private security is a key aspect of planning.
The Montreal Marathon, scheduled for Sept. 22, is a major event that draws large crowds, and a spokeswoman for the Montreal Oasis Marathon says it will be difficult to monitor.
“It's 42 kilometres. We can't check everyone in and out,” said Dominique Arsenault.
“But we're really trying to do the best we can as humanly possible.”
The Tour De L'Ile, Montreal’s popular cycling event, faces similar logistical challenges.
The cycling course, organized by Vélo Québec, will use fences and barriers to block off the city’s streets in June.
Joelle Sevigny, head of Vélo Québec’s special events, says while Monday’s incident was tragic, it shouldn’t stop people from enjoying public events like the Tour De L'Ile.
“We have to think how positive and healthy these events are collectively,” she said.