Twenty-five-year-old Dong Shuangyan blushed and took a step back when she heard the traffic light telling her "you've run the red light, please obey the traffic rules".

She was about to cross the zebra stripes in the crosswalk at Shangnan and Changli roads and realized she was not the only one who heard the lights speaking to her.

"It was such a moment of embarrassment when I figured out nearby pedestrians were staring at me," said Dong. "I have to admit running the red light isn't something nice to do despite the fact that I did it subconsciously."

Dong is not the only one who has been given a lesson by the talking traffic lights. Three intersections near Pudong's Expo site are equipped with the devices.

At first glance, these traffic lights look normal. But the pillar with a yellow sensor on top and an extra speaker can be found next to the lights if given a second look.

"They were placed here for the Expo and I really think they worked well - especially for those who usually wouldn't pay attention to the traffic lights," said Ji Hong who works in a nearby newsstand.

"Common reactions from pedestrians are to be surprised, embarrassed and step back."

The whole system includes audible and visual alarms, infrared detector, camera and speaker.

"When the offender is detected, the hidden camera will record the image. The information will immediately pass to the audio alarm and act as a cue," said Luo Zanwen, chairman of Shanghai Super Star Industrial Development Co Ltd, which is responsible for providing technical support for intelligent traffic lights in the area.

"The system has an internal memory of more than three hours, so it would be handy for traffic police if there's an accident."

Drivers have found the monitoring systems in their favor.

"I don't think it is fair to monitor vehicles and only fine us," said Miao Kanghua, a local resident who drives to work every day.

"Sometimes an accident happens because pedestrians ignore traffic lights and so in that sense, setting up such a device will help us tell who's responsible."