Parents saying they were "running late" dropping their children at school were among drivers caught flouting 40km/h limits in Gosnells yesterday, according to police.
Officers spent the morning targeting speeding in a school zone near Ashburton Drive Primary School and Southern River College.
Mothers and fathers with their children in cars were among at least nine motorists given speeding infringements on Southern River Road in just over an hour.
While officers were speaking to two motorists, one heard a small truck mount a kerb as it passed a turning bus on the same road. He said he saw the truck driver had his head down and suspected he was looking at his mobile phone at the time - a "recipe for disaster" in a school zone.
The road had flashing lights on the 40km/h signs, a crossing guard and dozens of children walking on the footpath so there was no excuse for motorists not to be aware they were in a school zone, police said.
A man in his mid-70s, who was stopped for speeding 12km/h over the limit, was not supposed to be driving because his licence was suspended for non-payment of fines.
The highest speed detected in the 40km/h zone yesterday morning was 63km/h.