Between January and October this year, police have issued 38 infringements and 48 cautions relating to illegal u-turns, although officers have said the actual number of incidents was much higher.

The situation has become so bad at one Gungahlin intersection that new road signs have had to be installed warning drivers not to perform illegal u-turns to avoid a collision with the light rail.

The signs have been placed at the intersection of Flemington Road and Wizard Street.

Video footage released as part of National Road Safety Week showed as many as four drivers do an illegal u-turn at the Wizard Street intersection just moments before a light rail vehicle was set to come through.

Executive branch manager of light rail operations for Transport Canberra Jo Dawson said the new signs were necessary for both driver safety and the safety of those onboard the light rail.

"We've noticed over the past 12 months there have been a number of people performing illegal u-turns and they have been reported by metro drivers," she said.

"It's a key area for reinforcement and we want people to be safe."

Since the opening of the light rail route to the Canberra public in April 2019, there have been eight near misses between the light rail and other vehicles where metro drivers have had to apply the emergency brakes.

In other news:

U-turns are not permitted at traffic lights unless there are signs saying the manoeuvres are allowed.

While road signs displaying that u-turns are illegal at traffic lights are unusual cross Canberra, the high number of incidents at the Flemington Road intersection forced the new measures to come in.

Detective acting inspector of road policing for ACT police, Ivan Naspe said u-turns were one of the most dangerous manoeuvres that could be performed by drivers.

"That's why there's so many restrictions as to where you can perform one," he said.

"No one likes missing their turn and having to go back, but you can only do a u-turn when it is safe to do so."