According to the UK Daily Mail, the device can scan 3,000 vehicles an hour and identify drivers of the biggest polluting vehicles in less than a second.
It could result in owners of cars that don't meet MoT emission limits being fined up to $200.
Transport for London is piloting use of the Accuscan 4600, a British-designed device which fires invisible infrared and ultraviolet laser beams through vehicles' exhaust fumes as they are driven past.
The Accuscan system uses lasers to detect emissions
At the same time it photographs the car's number plate and produces an almost instant analysis of each vehicle's emission levels.
It also detects excessive levels of particulates emitted by diesel vehicles, which have been linked to heart and lung dis-ease.
