A 60kph speed limit near the Bushrangers Bay car park entrance is designed to improve the safety of large numbers of people parking and walking next to a former 100kph section of Boneo Road.
The lower speed limit at Cape Schanck will be in force until the end of September. It will operate all day, every day.
Speedsters sailing through at the old speed risk a $702 fine and six-month licence suspension. Truck drivers could be fined $1652 with the same licence suspension.