Investigators remove the SUV involved in the hit and run on May 1, 2008. (Rick Donkers/CBC)

A Calgary man who admits to fatally crashing into a woman and injuring her son and a friend was so drunk that he had defecated in his pants, a court heard Monday.

Darren Coupal pleaded guilty to five charges related to the April 2008 crash, including impaired driving causing death — which carries a maximum life sentence — and two counts of impaired driving causing bodily harm.

Coupal drank at the Bull and Finch Pub on the evening of the crash, according to an agreed statement of facts entered into court Monday.

Witnesses saw him leave the pub and walk unsteadily towards a Dodge Durango SUV and drive away. Alarmed by his impaired behaviour, a couple followed him and called 911.

They watched as Coupal drove the SUV onto a sidewalk, shear off a bus stop sign and veer back onto the road, plowing into a group of pedestrians out for an evening stroll.

A broken bumper of the SUV that Coupal was driving can be seen under a tarp. (Rick Donkers/CBC)

Linda Davey, 39, died at the scene of the crash on Bridlewood Way Southwest. Her 15-year-old son, Josh, who has cerebral palsy and uses a wheelchair, was severely injured. He spent a month in hospital, including 11 days in an induced coma.

Fakhira Zadran, a family friend, 31, was also badly hurt. The crash narrowly missed three other pedestrians, including Fadran's daughter, eight, and Davey's daughter, also eight.

Coupal's vehicle then struck the centre median, rupturing the right-side tires, before hitting a small tree.

He fled the scene in the SUV, but witnesses followed him home, a little more than a kilometre from the pub.

Driver did not have valid licence

Police found Coupal standing on his patio, showing signs of impairment that included a fixed stare, bloodshot eyes and a strong smell of alcohol on his breath. He had also defecated in his pants, said the statement of facts.

"Coupal was aware that he had been involved in a collision but, due to his high level of intoxication and a minor head injury suffered in the collision, he was unaware that pedestrians had been run over," the document states.

"However, he did leave the scene in order to avoid civil and criminal liability."

Coupal did not have a valid driver's licence that night as a result of a July 2005 conviction for driving over .08.

Coupal, who was originally charged with 12 offences, also pleaded guilty to failure to remain at the scene of an accident causing bodily harm and driving while disqualified.

He's scheduled to return to court in February.

With files from Tara Fedun