I found an article in the Globe and Mail, 30 Dec 1960, page 4. It explains some details of the accident.
It was a 2 car accident - 4 people died, 2 in each car. Both drivers were killed immediately. Robert Osborne was a passenger in one of the cars. He and the passenger in the other car were injured, but both died later at the hospital. The other car was heading north on Don Mills Road. It skidded out of control in the slushy snow, and the south bound car (the one Robert was travelling in) hit the other car.
RK