Halifax Regional Police are asking people who may have witnessed a fatal car crash in Dartmouth that killed a 71-year-old man and shut down Main Street for hours on Monday afternoon to come forward.

The crash happened just before 4:30 p.m. after a black Jetta driven by a 17-year-old boy crossed the centre line on Main Street near Fader Street and crashed head-on into another car, said Halifax Regional Police.

Wayne Webber, of Dartmouth, was rushed to hospital with serious injuries following the crash but died in hospital a short time later. The 71-year-old driver was the lone occupant of his vehicle.

The lone occupant of the Jetta, the 17-year-old driver, remains in hospital with injuries to his legs.

HRP Sgt. Dave Reynolds said police are still investigating the cause of the crash.

"There isn't any definitive reason why the vehicle did cross the centre lane. And a lot of those answers will come in the following days once we've interviewed all of the witnesses — and some have yet to be contacted, as well as the 17-year-old driver of the Jetta himself," he said.

Accident reconstructionists who investigate crash scenes measure everything. The sooner they do it, the greater the accuracy of the investigation.

One piece of evidence police are investigating in this case is the speedometer inside the Jetta — locked at 100 kilometres per hour as a result of the crash.

"Well that's just one of those pieces of evidence that the reconstructionists take into account when they do all of their calculations and collect all of the evidence," said Reynolds.

He said people do often speed along the section of Main Street where the crash happened. Reynolds said police have handed out 700 speeding tickets near the crash scene in the past 12 months — about two per day.

Halifax Regional Police are now looking for the driver of a 1957 Chevy, who officers said may have been in the area at the time and witnessed the crash. They're also asking anyone else who may have seen the crash to contact police.