ABU DHABI // Federal transport chiefs are reviewing the law on lorry cargo limits amid confusion over the maximum weight that can be hauled by road.
The issue was highlighted last week when a lorry carrying 75 tonnes of aggregate ploughed into a bus taking 47 men to work, killing 21.
"The law on cargo load limits is currently being revised," said Nadhem As'ad Bin Taher, customer service chief at the National Transport Agency. "At the moment I believe each emirate is enforcing its own laws."
Overloading is illegal in Abu Dhabi and Dubai, punishable with a Dh500 fine, six black points and a seven-day confiscation of the vehicle. But neither police force specifies what is considered overloading, and operators believe they are free to haul up to the limits specified by the vehicle manufacturer.
The Roads and Transport Authority has a handbook on safe driving for lorries and buses, but the chapter on load limits is omitted from the copy on their website.
Amjad Hassan Al Saadi, operations manager of Roadlink General Transport in Abu Dhabi, said the maximum allowable load was calculated per lorry axle.
To his knowledge, the limit set across the UAE is 15 tonnes per axle.
Different lorries might haul a two-axle trailer, three-axle trailer or multi-axle trailers of up to 30 axles. The lorry involved in the fatal Al Ain accident, he said, had three load-bearing axles and was pulling a three-axle trailer.
"The trailer is made to carry 45 tonnes, while the front side can carry up to 30 tonnes, meaning the maximum should be 75 tonnes."
Another operations manager at a transport company in Abu Dhabi said transport companies used both the lorry axle and the available cubic metres to compute the maximum weight limit. "The lorry that crashed can hold up to 75 tonnes of sand," he said.
But a heavy-vehicle dealer in Dubai said that according to most manufacturing specifications, a 6x4 metre trailer can haul a maximum recommended payload of 45 tonnes, while 6x4m chassis lorries typically have a 32 tonne payload.
The 15 tonne per axle rule also seems high when compared with laws in other countries.
Australia, Canada and Britain - all countries with proven traffic safety records - have complex policies when it comes to the maximum weight a lorry can haul.
Canada's policy differs by province but lorries are generally limited to hauling no more than 63.5 tonnes. In the UK, provided the tractor and trailer both have three axles each, a lorry may haul a maximum of 44 tonnes. That works out to just over seven tonnes per axle.
In Australia, the limit is set at 42.5 tonnes on most lorries, although special permits can be applied for to haul as much as 164 tonnes in a four-trailer road train - with an absolute minimum of three axles per trailer. The per-axle limit works out to about 13 tonnes.
In the United States, the Federal Motor Carrier Safety Administration regulates weight limits of commercial motor vehicles. The federal gross weight limit for big lorries is 80,000 pounds (36 tonnes).
Abdulilah Zineddin, a road safety expert in Abu Dhabi who has a doctorate in civil engineering, specialising in traffic engineering and safety, said attention should also be paid to ensuring the contents of a vehicle will not spill out. A cover should be used to contain or confine a load driven on a motorway, he said.
"I don't see lorries being covered properly here in the UAE compared to the US," said Dr Zineddin. "They should be carefully sealed."