The third crash was at 7.20am yesterday morning, when a Marton woman driving to work in Whanganui went off the road before the bridge and was trapped in her car.
"I heard the car leave the road and called to my son to come and help," O'Shanassy said.
"We couldn't see the car at first because she had ended up in the creek as well.
"The lady was leaning on her horn to attract our attention."
The driver was assessed and treated at the scene.
None of the three drivers was seriously injured.
The road has recently been re-surfaced and there are traffic cones and signs asking motorists to drive at 50km/h.
Rangitikei District Council spokeswoman Carol Downs said the signs previously had a 30km/h limit.
"Police attended the crash this [Friday] morning and they are satisfied that it is safe to drive at 50km/h on the stretch of Rd. The road has been swept for loose gravel."
A police spokesperson confirmed all three crashes had been reported and urged drivers to stick to the speed limit.
"While roadworks can be frustrating, traffic management measures within roadworks sites are there to keep road users and construction workers safe," she said.
Grant O'Shanassy said he feared for his own safety at times as the road runs through his property.
He is glad no-one was seriously injured in the recent crashes and hopes drivers will adhere to the speed limit.