The PSNI have carried out a reconstruction of last Saturday's bomb attack in Londonderry.
The explosion occurred in Bishop Street at about 20:15 GMT shortly after police received a warning.
Police believe the attack may have been carried out by a dissident republican group, known as the New IRA, and have issued a fresh appeal for information.
"It is only out of sheer luck nobody was killed or maimed," Ch Insp Stuart Griffin said.
"Did you see a grey coloured Ford Fusion, WCZ 2167, which was hijacked in Quarry Street and driven to Bishop Street via Barrack Street?
"Did you witness anything unusual or see any other vehicles in the area at that time?"
The PSNI are also asking people to check their dash cam footage.
"We know that a number of young teenagers walked past the bomb right before it detonated and while they were not the intended victims, this clearly demonstrates that these terrorists do not care about the safety of those living in this community," Ch Insp Griffin added.