Is there a cross-wind speed at which double decker buses are forbidden to operate?

Megan Pledger made this Official Information request to Ministry of Transport

The request was successful.

From: Megan Pledger

Dear Ministry of Transport,

Can you tell me if there is a cross-wind speed (average or peak) for which double-decker buses are not allowed to operate? As an example, I am thinking of the new double decker buses operating on Cobham Drive in Wellington.

If there is such a speed then whose job is it to monitor the wind speed and tell the drivers not to operate?

Yours faithfully,

Megan Pledger

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From: Roselle Thoreau
Ministry of Transport

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Dear Megan,


There is no current by-law regulating the operation of buses specifically
in high winds in NZ. There is a criteria for buses, including
double-deckers to be stable when tilted to various angles but that is
quite a different scenario to wind. The NZTA looks after these criteria.


In other countries there are rules related to regularly experienced high
wind. For example, in Hong Kong bus services are suspended for the Tsing
Ma Bridge when the recorded wind speed exceeds 75km/h. Note, however, that
there is a relationship between the recorded wind speed and the expected
maximum gust speed on the Tsing Ma Bridge so that the authorities
acknowledge a much larger wind speed may be experienced for buses crossing
the bridge. 


In New Zealand the NZTA issues warnings related to weather conditions for
all 'high-sided vehicles', eg. "High winds mean that drivers of high-sided
vehicles, towing caravans or driving campervans should stay put, well out
of the wind". 


All current road closures and warnings will be updated in real time during
a storm event at [1]  Drivers can
also call 0800 44 44 49 for 24/7 updates on road conditions, closures or
delays. The latest severe weather information is available at


Please find attached a paper that outlines the crosswind effects on
buses.  This material is a comprehensive account of the wind loadings on









Dr Roselle Thoreau

Principal Data Analyst, Analytics & Modelling

Ministry of Transport - Te Manatu Waka

T: +64 022 019 7381 | E: [email address] |


Enabling New Zealanders to flourish



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