Liberal Senator Roméo Dallaire told Senate colleagues Tuesday afternoon that the car crash he had on Parliament Hill earlier in the day was caused by a lack of sleep due to reliving the events he saw as a general during the Rwandan genocide and the apparent suicide of three Afghan war veterans last week.

"On my way to work this morning, I fell asleep at the wheel and crashed into the barrier near the East Block with my car. I am very thankful that nobody was injured or worse by my not being more attentive to the level of fatigue that I have been experiencing," Dallaire told the Senate.

In an interview with CBC News Network's Power & Politics on Tuesday, Dallaire said he was unhurt, but that his biggest fear had been for the safety of others.

"I'm OK, because I was completely asleep and in so doing didn't see anything coming, so when the airbags blew open, I was sort of like a rag doll, so I have no injuries, no whiplash or anything. The gravest element of that was my fear that I had hit somebody, because the Hill is always full of people."

The senator's black BMW skidded off the road, past the sidewalk and onto the snow-covered grass before hitting a lamp post on Parliament Hill. Liberal Senator Roméo Dallaire was involved in a single-vehicle accident on Parliament Hill Tuesday morning, the apparent result of sleep deprivation. (Lorian Belanger/Radio-Canada) "I was out cold, just like that."

Dallaire, a retired general, said he is still battling post-traumatic stress disorder two decades after heading up the UN peacekeeping mission in Rwanda.

The Liberal senator was the force commander of the United Nations Assistance Mission in Rwanda​ leading up to and during the 1994 genocide.

Dallaire told host CBC host Evan Solomon that alcohol was not a factor in the accident.

"I'm not allowed drinking. I have not had a drink in 12 or 13 years now," Dallaire said.

The senator, who in the past has attempted suicide, explained that he hasn't had a drink in over a decade because of the antidepressants he is on to treat his PTSD.

Dallaire told Solomon he will be attending a therapy meeting on Thursday and will avoid driving unless he has to.

PTSD triggers

As the 20th anniversary of the Rwandan genocide approaches in April 2014, Dallaire told the Senate he has been reliving those events. Not only that but the apparent suicides of three Afghan war veterans last week have also had an effect on him, he said.

Dallaire told his Senate colleagues those events have affected his ability to sleep, despite taking prescribed medication to help him cope.

"I simply ran out of steam," the senator said.

Dallaire said he regrets taking such a risk and not paying more attention to his physical condition.

"I hope it brings no dishonour to you or to this institution," Dallaire said.

Roméo Dallaire's BMW is towed after he crashed into a lamp post. (Lorian Belanger/Radio-Canada)

The RCMP closed the road to traffic while Dallaire's car was towed.

RCMP say that "like alcohol, fatigue impairment slows reaction time, decreases awareness, impairs judgment and increases the risk of crashing."

Dallaire is an Officer of the Order of Canada, a Grand Officer of the National Order of Quebec, and a Commander of the Order of Military Merit.​

He is also the author of two bestselling books stemming from his experience in Rwanda and is currently working on a third book.