One car had been towing a trailer and the road was not reopened until 10.40am due to transmission fluid that was on the road and a tow truck being required.
A St John Ambulance spokesperson said they assessed six people at the scene but none needed to be transported to the Hawke's Bay Hospital.
Fire Service communications shift manager Murray Dunbar said two engines from Napier and one from Hastings attended the crash but were stood down shortly after arrival.
The car crash backed up traffic both north and south in the off ramp in what was an already-congested area due to nearby road works near Links Rd.
Senior Sergeant Foley said while motorists speeding through road work sites had been an issue for some time, it had been particularly bad as of late.
"For quite some time we've been having a bit of a problem with people not obeying the speed reduction signs.
"People are going through at the standard speed which makes it dangerous for them because the road has changed and the road workers who are working on those sites."
Police had recently clocked someone driving at 122km/h through a speed reduction area, he said.
"The reason we set those speed limits is for people's safety and if they go over them they're putting their health and safety at risk."
He said the public should be warned that police would be keeping a closer eye on road work sites from now on and encouraged motorists to abide by the reduced speed limits.
"You are going to have to slow down. Those road signs are there to protect the drivers as well as the road workers. There's a lot of uneven surfaces, some big drop offs and it really is a more dangerous pieces of road than it used to be."
