Police are ramping up patrols in Belfast in an effort to curb the surge in increasingly brazen carjacking attempts.
A specialist auto crime squad has been set up by the PSNI to try and bring the current spate of hijackings under control.
Motorists were confronted in two attacks in the city centre on Thursday evening when they were sitting in traffic.
The first incident happened around 5.45pm in the North Queen Street area when a man tried to open the front passenger door of a blue Vauxhall Corsa.
The door was locked and he was unable to gain access.
Just over an hour later another attempted theft took place in the York Street/Westlink area when a man approached a red Seat car and tried to open the passenger side and rear doors of the vehicle which were locked.
A similar bid was made on Wednesday night when two men tried to open the doors of a car on the York Road.
They fled when unable to open the car's doors. The female driver was uninjured.
Many of the car crimes are blamed on the Divis Hoods, a notorious gang operating out of west Belfast
Detective Chief Inspector Gary Reid said: "It is believed that in these two incidents (on Thursday) the objective was to gain access to the inside of the vehicles in order to make off with whatever items were sitting either on the seat or in the foot well. No one was injured in either of the incidents.
"There has been an increase in police patrols within the Belfast area but I would ask motorists to take personal responsibility by ensuring that any items or goods are stored safely in boots of vehicles and that doors remain locked at all times whilst in the vehicle."
Earlier this week two men pulled a woman from a silver Nissan Micra while she was stopped at traffic lights on Divis Street.
They made off in the car, which was found abandoned in Kilmore Close in the city.
At midday on Tuesday a delivery van driver was getting a parcel from the back of his van when three men tried to bundle him into the vehicle. He managed to get away.
Both victims were unhurt, but left badly shaken by their experiences. A police clampdown on thieves in 2012 seemed to have largely stamped out the opportunist crimes.
But a new spate of hijackings, mostly targeting vehicles of women and young people, has given rise to deep concern that another wave of attacks is gathering momentum.
In the past year there have been more than 2,200 car thefts or related car crimes across Belfast - more than 40 a week. Around 80 of those crimes were hijackings. A dedicated PSNI car crime probe - Operation Galleas - is under way to tackle the problem.
Earlier this week Belfast City councillor Jim Rodgers warned somebody could be killed if carjackings are not halted by police soon.