Nearly one in three people sitting restricted licence tests in the region don't get the chance to complete them.
NZTA figures show the region's termination rate for restricted licences in Manawatu-Whanganui was 32 per cent between January and September.
The figure refers to tests not completed due to an immediate failure error or the accumulation of several critical failure errors.
Immediate failure errors include collisions, failure to give way, excessive speed and failing to stop. Critical errors include going too slowly or too fast and failing to look or signal.
Drivesafe Driving School owner Jack Kennedy said Whanganui's test circuit was the best he'd seen in his 30 years in the job. It was fair and had different types of roads.
"It's not a hard test... People are failing because they haven't done the homework I find. It's pretty simple."
Restricted licence test were most often cut short during the first, easiest stage of the test.
If drivers couldn't make it through the easier part, this suggested they could be unsafe during the harder stage, said Mr Kennedy.
People might have full licence tests cut short because they were busy concentrating on their commentary and broke basic road rules.
"It's just homework again."
Mr Kennedy said drivers had been coming to him more prepared since restricted licence tests were made more difficult in 2012.
According to the NZTA, the terminated rate for full licence tests in Manawatu-Whanganui was more than one in five, or 22 per cent.
Last year, 36 per cent of restricted licence tests and 20 per cent of full licence tests were terminated.
In 2013, shortly after the restricted licence test was made more difficult, 36 per cent of Manawatu-Whanganui people had their restricted tests terminated and 20 per cent had their full licence tests terminated.
NZTA said candidates could also fail a practical driving test by having it cancelled before driving started because they didn't have their licence with them, the vehicle wasn't roadworthy, or they weren't familiar with basic controls in the vehicle.
They could also be failed due to an accumulation of minor errors throughout the test.
NZTA national media manager Andy Knackstedt said pass rates for practical driving tests were also influenced by factors such as the road and traffic environment.
The most important determining factor for each person's likelihood of passing the test was how much that driver has practised and prepared for the test, said Mr Knackstedt.
The overall national pass rate for the more challenging restricted licence practical test had increased from 40 per cent, after its introduction in 2012, to more than 60 per cent currently.
"The Transport Agency's focus is on quality and consistency in testing, and therefore on ensuring safe drivers, not on pass rates," said Mr Knacksteadt.
Nationwide, 35 per cent of restricted licence tests and 27 percent of full licence tests were terminated between January and September this year.
Sitting a restricted licence has a $48.20 application fee - with another $86.60 for the test. A full licence has a $49.60 application fee, with $59.90 for the test.
If you have to re-sit, you pay another test fee but not another application fee.