Prices plummet at pumps but firms not seeing benefit
The cost of filling up a car with petrol is £2 less than a month ago and diesel prices have also fallen.
But hauliers in Northern Ireland are not seeing the benefits, an industry body has said.
A six-year low in the price of oil helped bring the average cost of petrol down by 4p a litre to £1.12 in the last week of August, RAC Fuel Watch said.
Diesel also continued to drop throughout the month with a further 5p shaved off a litre, taking the average price down to £1.10, keeping it below petrol.
According to PetrolPrices.com, the lowest-priced diesel in Northern Ireland yesterday could be bought at Sainsbury's in Coleraine at £1.059 per litre, compared with an average in the UK of £1.099.
The supermarket also had the cheapest petrol at £1.079 per litre, compared with a UK average of £1.115.
But the impact on businesses which use a large amount of fuel is not significant, according to Seamus Leheny, head of the Freight Transport Association in Northern Ireland.
Its 320 members includes haulage companies such as Montgomery Transport and Sawyers, as well as major companies such as Moy Park which operate their own fleet.
Mr Leheny said around 95% of hauliers ran their vehicles on diesel but were not seeing immediate benefits.
He added: "It is having a positive impact but not as much as it ought to have."
He said bulk diesel prices had fallen by around 14.4% a litre to 90p per litre since July 2014 but crude oil prices had fallen by nearly 50% year-on-year.
The relative weakness of the pound against the dollar was one of the factors which meant the full benefits of the 50% fall in crude oil weren't being passed on. And he said high fuel duty of 57.95p per litre - among the highest in Europe - was also having an impact.
"Fuel duty is dampening the impact of the reduction in the price of a barrel of crude on oil prices. However, without fuel duty the reduction in price more than doubles to 32%."
In the run-up to August oil was at a consistent $60 a barrel, but dipped to a low point of $41.87 on August 24. RAC fuel spokesman Simon Williams said: "We thought July had been a good month for motorists but August proved to be better still due to world oil prices reaching their lowest since February 2009.
"Diesel drivers have benefited the most this summer due to a new supply of diesel from Saudi Arabia bringing the wholesale price down.
"They are now paying £5.60 less to fill up than they were at the beginning of July whereas the savings for petrol motorists have only just kicked in with the drop in the price of oil feeding through into lower wholesale and retail prices."
The lowest price per litre of diesel on sale in Sainsbury's, Coleraine