Council transport operations manager Martin Parkes said lowering the speed limit did not mean motorists would adhere to it. "Compliance is quite good for 80km/h."
He said the council would have to bring in some physical measures onto the road to bring down speeds because otherwise it would not work.
Mr Fitzgerald argued that motorists would respect a 60km/h speed limit and that police were willing to enforce the lower limit. He highlighted difficulties residents had exiting their driveways where there was limited visibility and they had to accelerate hard to get up to the speed of traffic.
Mrs Fitzgerald said she took her life into her hands with traffic approaching from behind every time she turned into their driveway. "We should not wait for a tragedy to happen before common sense prevails."
Mr Parkes said the legal process to lower the speed limit could take "several months" before the issue came back to council.
Councillor David Stewart said the Road Transport Association representing the trucking industry favoured lowering the speed limit.
Councillors were surprised at Mr Fitzgerald's recent peak-time traffic counts of 1035 cars, 64 trucks and 16 buses from 7.30am to 8.30am; and 898 cars, 60 trucks and 15 buses from 3.30pm to 4.30pm.