The Waterview Tunnel construction is up for an award at the Civil Contractors' National Awards next week.
The nomination comes after weeks of largely positive feedback about the tunnel, which has cut some Aucklanders' commute times by half and sped up trips to the airport considerably.
It is up against two other finalists in the category for projects of more than $100 million: the Mackays to Pekapeka Expressway north of Wellington and the Christchurch Infrastructure Rebuild.
System design manager Brett Gliddon, who works for the NZ Transport Agency, said feedback from road users so far had been "fantastic".
Traffic had been flowing well and congestion was noticeably reduced during peak traffic times.
Unfortunately for those wanting to travel through the tunnel at higher speeds, the variable speed zone would not go above 80km/h.
It was all about best practice, Gliddon said.
"We design the tunnel for operating at 80km/h because when you have accidents the consequences in the tunnel are more severe than outside of it."
Changes to the motorway also meant parts of it were now more complicated, so driving at a lower speed gave people more time to make decisions about things like which lane to move into.
"With the tunnel coming on board there's a lot more weaving and decision-making needed."
The variable speed zone meant maximum speed could be lowered to 30km/h as needed to control traffic flow, but so far that hadn't been necessary, Gliddon said.
Last Friday, the police announced four speed cameras would be operating at the tunnel and hoped advance messages warning about the cameras would not result in any tickets.
The police said today that it was too early to say how many speeding tickets had been issued since Friday because of the standard processing time delay.
"This data is expected to be proactively released as soon as is practicable in line with police's standard quarterly reporting," a police statement said.
The road policing manager of operations, Inspector Pete McKenzie, said monitoring of traffic flows through the tunnel before the cameras were introduced had been encouraging, with average traffic speeds below 80km/h.
"While our preference would be not to issue any notices, the 80km/h speed limit is in place for good reason to keep everyone safe, so we won't hesitate to prosecute where appropriate."