Both ANZ Truckometer indexes fell in November, although the economic indicators both have solid upward trends.
The Heavy Traffic Index, which covers the same time period as GDP, is maintaining high levels after a very strong third quarter.
The index fell 1.5% after heavy traffic flows fell in 10 of the 11 roads measured in the index.
While GDP data on the third quarter will not be available until later this month, ANZ is tipping it to be about 1.3-1.5% -three times the growth the economy managed in the first two quarters of 2013 combined.
The light traffic index fell 1.1% in November after rising 1.8% in October.
Light traffic fell on all but one of the ten roads measured in November.
The upward trend remains evident in this index, suggesting economic momentum will continue well into next year.
A flatter trend suggests slower growth in the first half of 2014 than the second half of this year.
ANZ says the economy is currently in top gear but a strong bounce back in primary sector is unsustainable; so slower growth in the first half of 2014 will not be alarming.
ANZ says credit growth is also key and, if old borrow-and-spend behaviours remerge and the Reserve Bank has to step in, it will dampen the generalised economy expansion.