Last year, Road Safety Minister Shane Rattenbury made changes allowing the vans to be placed in school zones for the first time.

A total of 43 sites at ACT schools will now allow mobile speed cameras, in an attempt to reduce speeding and improve road safety.

School speed zones were traditionally enforced by police, Mr Rattenbury said, but vans were recognised as a big deterrent.

"Generally across the city, the more they're out there, the lower levels of speeding we see. Bringing them into school zones adds a new layer of safety enforcement for our school zones, where our most vulnerable people are, the students who don't have the road safety sense always to take care of themselves."

The government plans to have as many school zones as possible approved for speed van use by the end of 2016; although some schools are unsuitable for the vans because of line-of-sight issues.

Since October, the vans have been stationed at school zones more than 200 times, checked the speed of more than 80,000 vehicles, and 1177 speeding fines have been issued.

In some school zones, cars have been clocked at 80km/h.

Justice and Community Safety Directorate manager of road safety Geoff Davidson said, "We need to recognise, as a community, that the 40km/h school zones are legitimate ... there are physical limitations in what the human body can sustain. .

"In a crash between a pedestrian and a car, impact speeds of anything above 30km/h are likely to result in death. That's the very reason why we've got 40km/h limits in school zones, but also in other areas like town centres, where we see a lot more pedestrians and cyclists."

The 40km/h limit takes into account a driver's corrective actions such as braking, Mr Davidson said, which lowered an impact speed.

In this year's ACT budget, funding was made available for two extra mobile speed vans, which are set to be on the road later this year.

Deirdre Sharkey's children, Owen, 9, and Alice, 7, Radajewski go to Majura Primary School, a site that now allows mobile speed vans.

She said that it was sometimes worrying the speed at which people drove past the school, especially at drop off and pick up times, and she hoped the vans meant drivers thought more about speed.

"It just makes sure that people slow down. We've got a preschool down there, so it is actually a long stretch of road for people to go at 40km/h," she said.

All mobile speed camera sites can be found at www.justice.act.gov.au (pdf).