It happened around 9:00 p.m. Monday in Lower Providence Township.
Police say the woman was driving on Evansburg Road when she was pulled over by a man driving a small 4-door vehicle with a flashing blue light mounted on the dashboard.
Both cars stopped in a gravel parking lot at the intersection of Evansburg Road and Germantown Pike. The man got out of the car, approached the woman, spoke with her, then left. The woman was not harmed.
The suspect has been described as a white man in his 50s with short brown hair. New details released Thursday include the suspect's height and weight: 5'11" tall and 190 pounds. Police also say he was wearing a dark Emergency Medical Technician (EMT)-style uniform with a circular patch on the left sleeve. No badge was displayed on the uniform.
The vehicle he was driving is described as a small, four-door tan vehicle with tinted windows and a blue dashboard-mounted light.
Anyone with information about the incident or the suspect is asked to call Lower Providence Police at 610-539-5901.
Police also issued the following advisory to motorists traveling in the area:
The Lower Providence Township Police Department would like to advise motorists that vehicles equipped with only blue lights are not authorized to effect vehicle stops in Pennsylvania. Police vehicles in Pennsylvania, both marked and unmarked, must be equipped with a combination of red and blue emergency lights.
Also, if you are being signaled to stop by an unmarked vehicle that you believe may not be a police vehicle you may continue to drive at a slow speed to a safe, well lit, populated area before pulling over. You may call 911 and advise them that you are being stopped by a vehicle that you believe may not be a police vehicle and the dispatcher may advise the officer of the reason that you are not stopping.
Once you have stopped for an officer in an unmarked car, you may request that a marked police unit respond, as well, to confirm that the unmarked police vehicle is legitimate.