Petrol prices have reached a six-month high, causing many motorists to reduce their car use, according to the AA.
The average price of petrol nationwide is now 117.19p a litre – up from 116.42p a month ago and above 117p for the first time since mid-December 2014.
Diesel is now averaging 121.0p a litre compared with 120.7p in mid-May.
Since petrol prices tumbled to their lowest price on 1 February this year, average prices have crept up by more than 10p a litre.
An AA/Populus survey showed that 37% of the 28,080 AA members polled had already started to cut back on car use, with this figure rising to 48% for lower-income drivers.
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Fuel duty speculation
AA president Edmund King says "Our fuel report this month illustrates vividly the power of pump prices on consumer spending.
"It sends out a clear message to government on fuel tax: don't be mistaken into thinking that because pump prices are 13p-a-litre lower than this time last year that drivers are ripe for another fuel duty increase."
But a Treasury spokeswoman says: "By the end of 2015/16, fuel duty will have been frozen for five years – the longest duty freeze in over two decades. The Government's action on fuel duty is saving families around £10 every time they fill up their car."