Victorian motorists are still driving too fast despite a jump in the road toll, authorities say.
In 2021 so far, 156 people have died on the state's roads, compared to 148 people at the same time last year. Speeding has contributed to 30 per cent of those fatalities.
Transport Accident Commission research shows about two-thirds of drivers believe it's safe to break the speed limit by up to 10 km/h.
But the TAC research shows the risk of crashing increases by a quarter at three kilometres over the limit, and by half at five kilometres over.
The risk of a crash doubles at 10 kilometres over the limit.
Authorities have pinpointed Punt Road and High Street in Prahran as a particular issue, with a 172 per cent increase in speeding from July to September 2020, despite traffic dropping by almost half during that time.
At Terminal Drive and Centre Road near Melbourne Airport, speeding fines increased by 160 per cent during the last three months of 2020.
"Less traffic on our roads is no excuse for dangerous driving," Police Minister Lisa Neville said in a statement, warning police would throw the book at speeding motorists.
Mobile speed camera hours have increased by 75 per cent and 35 extra cameras will be installed at high-risk intersections, the state government says.