Police issued more than 390,000 speed camera tickets, totalling $25 million in fines, until September 13 - a drop of 98,760 tickets from the same period last year.
National road policing manager Superintendent Steve Greally said the drop in speed camera tickets was "very encouraging", as it showed road safety was improving.
But speed was just one of the potential killers on the nation's roads, he said.
"It's not only speed that contributes to the road toll, it's a variety of things like drugs, alcohol and cellphones," he said.
The drop in issued tickets also led to a $5.9m drop in revenue.
The figures - released to the Herald on Sunday under the Official Information Act - do not include motorists who were caught driving in excess of 50km/h over the speed limit. Those offences are dealt with via the court system.
All fixed speed camera sites have been assessed as being at high risk of speed-related crashes.
Greally said the success of the cameras wasn't judged on fines generated, but on making the roads safer.
"A reduction in infringements is a great thing. It's never, ever, about the money," he said.
"We're the ones who have to inform families that loved ones are dead. I've never met a cop who enjoys that."
Despite the drop in speed camera tickets, more people are dying on the roads.
The provisional road toll for 2015 is 321, the highest since 2010.
The holiday road toll stands at eight. Eleven people died during last year's Christmas-New Year break.
Traffic safety campaigner and editor of car review website dogandlemon.com Clive Matthew-Wilson said the speed camera figures showed the risk of a fine wasn't deterring dangerous driving.
He wanted police to rethink road safety measures.
"This huge number of tickets suggest the cameras are a failure," he said.
"The police have a deliberate policy of positioning cameras without warning.
"These cameras tend to catch motorists who are often simply travelling at the same speed as the motorists around them, without intentionally breaking the law," he said.
"These same motorists would have probably slowed down anyway if they had been warned first, so nothing has been gained."