The bus became stuck on two of the three sets of tracks and could not be freed by the driver who tried several methods.
The report made a number of recommendations about the layout, profile and stacking distance issues at the Beach Rd crossing and others around the country as a result of the investigation to improve safety.
KiwiRail has identified were 252 level crossings with less than 23 metres' distance between the centre of the nearest railway line and the edge of an intersection.
The collision rate across all those crossings was 6 per cent higher than the collision rate at crossings with no nearby intersection.
NZTA was unable to provide APNZ with a full list of the affected crossings, but noted in its response to the report that nine had been the site of two or more collisions.
Five had since been upgraded and there had been no further collisions.
NZTA spokesman Andy Knackstedt said it was working closely with KiwiRail and road controlling authorities to improve the safety of existing level crossings and ensure future crossings were safe for long vehicles.
"We're also working with the Bus and Coach Association and other public transport and commercial vehicle operators to identify measures to help improve the safety of buses and other large vehicles at intersections near level crossings."
Mr Knackstedt said some of the intersections had very low volumes of vehicle and rail traffic, and NZTA's priority was to focus on intersections where the potential risk was the highest.
"Many of our level crossings date back to much earlier days when road vehicles up to 23m long didn't exist. As such, while reconfiguring some of these intersections to better accommodate the needs of our modern vehicle fleet will be a challenge, we'll be working closely with our partners to identify practical solutions that will help to reduce the risk of these collisions in future."
KiwiRail spokeswoman Jenni Austin said it welcomed the report and had worked with NZTA to identify the crossings.
The report also recommended drivers of large road vehicles should carry the National Train Control Centre emergency telephone number so they could alert the train controller in any similar situation.