The council's transport and waste solutions manager Stavros Michael said the average speed along Clayton Rd was 57km/h - 7km/h above the speed limit - and 15 per cent of drivers were going 63km/h or faster.
He said the new speed bumps were being installed for safety, to reduce average speeds and in response to complaints about speeding made by locals.
"All affected residents have been notified," he said.
But Rotorua's Rusty McKnight, who drives along Clayton Rd and back every day, said there were enough speed bumps along the road and questioned the need for more.
"Around 90 per cent of us who drive properly have to drive home over these things every day. Once again the council is wasting money.
"Take them all out, let's drive home on a smooth surface and let the police deal with speeding offenders," Mr McKnight said.
Efforts to speak to local schools and a nearby playcentre were unsuccessful last night.
Speed bumps:
* Four new speed bumps for Clayton Rd
* There will soon be 12 along Clayton Rd
* Cost to install is $27,000
* Average speed on Clayton Rd, 57km/h
* Speed limit is 50km/h