During that period, NZTA staff went 101km/h or more on 32,784 occasions. There were also 2123 instances of travelling at 110km/h or more.
NZTA chief executive Geoff Dangerfield said yesterday the speeding data would not be sent to police.
"None of these things in the data have resulted in any infringement notices at all. It's not the right thing for us to hand this over to police. We didn't do this [put GPS in vehicles] from a sanctions point of view but from a health and safety point of view."
Labour's transport spokesman, Phil Twyford, said the police needed to step in. "This is so extensive and some of these cases are so extreme: I would call on the police to look into whether or not they have the legal power to prosecute. The police need to have a hard look at this."
Speeding staff members included a member of the senior leadership team and a handful of managers. The exact number of cars speeding is still being determined but a three-month sample of the data showed at least 45 of NZTA's 139 cars were found to have been driven "consistently at speeds over 110km/h".
The Herald found 8500 occasions on which NZTA cars were driven faster than 110 km/h - well over any unofficial tolerance allowed in speed enforcement. There were 910 instances where the cars were driven at speeds greater than 120km/h - and 130 instances of speeds more than 130km/h.
Of those, there were eight cases in which speeds topped 140km/h, with at least one vehicle going more than 145km/h. Five of those were the same car near East Cape.
Transport Minister Simon Bridges said he was unhappy the agency he led had failed to lead by example.
"To say I'm unimpressed would be one of my big understatements. I'm very disappointed. Road safety is a clear government priority and [for] a road safety agency I'm sure New Zealanders would expect it to lead by example."
National manager road policing Superintendent Steve Greally said GPS data alone would not stand up in court and for further action to be taken for this type of offending it needed to have occurred within six months of the alleged offence.