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.
See MoneySavingExpert.com's Cheap Petrol and Diesel guide for tips on cutting prices and improve fuel efficiency.
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."