New speed limit signs on Vasse Yallingup Siding Road which were installed on the weekend were all knocked over by Monday morning.
Main Roads installed the signs to indicate to traffic that the the speed limit along Vasse Yallingup Siding Road had been reduced from 110 kilometres per hour to 90 km/hr.
A Main Roads spokesperson said the new signs had all been hit by one or more vehicles.
"The maintenance crews are heading to the locations and these signs will be reinstalled today," the spokesperson said.
Last week, farmers Ian and David Carter approached the Mail calling for action after the speed limit had not changed since Transport Minister Rita Saffioti gave her support in May last year.
"Within 10 minutes of waiting for the school bus you will see commuters, trade vehicles with trailers and trucks all going too fast," David Carter said.
"While it is a defacto route between Vasse and Dunsborough, the next road, the brand new Vasse Bypass has big curves, big shoulders and big visibility but is limited to 90km/hr.
"There are enough dead roos on the side of the road, it is also used by cyclists and children who catch the school bus.
"Sooner or later someone will lose the battle against the tree."
Vasse MLA Libby Mettam said in the interests of the safety of local residents and road users, she was happy that this speed reduction signage had now been installed.
"There is a high volume of traffic that utilises this relatively narrow road, including school buses, trucks, vehicles and cyclists," she said.
"There have been a number of serious accidents along this dangerous stretch of road which supports the need for the speed reduction."
The RAC reported earlier this year, that statistics from Main Roads showed the number of fatalities were higher on roads with 110km/hr speed limits.
From 2013 to 2017, there were 342 accidents in 110km/hr zones on regional WA roads which were fatal.
City of Busselton councillor Rob Bennett said the speed limit reduction had been a long haul and took a lot of persistence to get it changed.
"It will make that stretch of road a lot safer," he said.