Delhi Traffic Police: Hit-and-run cases or accidents by “unknown vehicles” have also come down this Jan compared to last year. Forty-seven such accidents have taken place this year against 50 accidents last year. Last Jan, 51 people were killed by unknown vehicles and the figure was 47 this Jan, the data compiled by the police shows. Scrutiny of data of “day and night accidents” revealed that most of the simple crashes occurred during the day, while fatal crashes took place more during the night.