A report by NTI based on the insurance specialist’s National Truck Accident Research Centre report on truck accidents, shows us that the reasons behind milk tanker accidents are more than just tanker slosh.
The latest NTARC report shows that, on average, dairy tankers are 2.4 times more likely to be involved in a crash than other freight transport types.
Road and farm access conditions can limit the usable types and sizes of trucks. Many minor roads will not allow B-double or PBS vehicles access. To complicate this further, many farms on suitable B-double and PBS routes lack safe driveways for these combinations.
Sloshing and surging present the greatest risks when tanks are 40 to 70 per cent full. If a vehicle is in this load range and on a high-risk road section, it will be significantly more challenging for a driver to maintain control of their combination.
The most significant difference is the frequency of inappropriate speed crashes. These are predominantly single-vehicle ‘untripped’ rollover crashes. For dairy tankers, they represent one-third of all major incidents (32 per cent) compared to one in eight for all unit types (13 per cent).
Another critical difference in the dairy tanker crash data is the proportion of single-vehicle crashes: 80 per cent only involved the tanker, compared to 59 per cent for all unit types.
NTARC’s data show that the leading causes of single-vehicle ‘untripped’ rollovers for dairy tankers are inappropriate speed (32 per cent), inattention/distraction (20 per cent) and not at fault (16 per cent).
For other unit types, the leading causes are inattention/distraction (16 per cent), inappropriate speed (13 per cent) and not at fault (12 per cent).
Slosh, in particular, can elevate crash risk as it raises a tanker’s centre of gravity and generates significant centrifugal force, pushing the tanker outwards on a curve. It is particularly dangerous when a tanker is around half full (40–70 per cent) as the load has significant mass and room to move.
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