Trials of new technology that NSW plans to implement to spot drivers illegally using their mobile phones have also captured motorists in 80-to-100km/h speed zones who are texting with both hands, eating, reading and using illegal drugs.

A man illegally using nitrous oxide (known as nanging) while driving down a highway at 100km/h was among those captured on camera in scans of about 100,000 drivers across Australia.

A man prepares to inhale nitrous oxide while speeding down the highway. Credit:One Task

Another driver was seen texting with both hands, said Alex McCredie, the director of One Task, which conducted the tests. Others were snapped with both hands off the wheel and in the air, with pets in their laps or unrestrained, doing their makeup, and reaching for objects.

One Task's surveillance found illegal mobile phone use was endemic, with between 5 and 7 per cent of drivers in every city using them while driving at high speeds.