The AA said motorists should “walk or cycle to save money”.
The average price of a litre of petrol at UK forecourts reached a new record of 183.2p on Thursday, according to data firm Experian.
That is an increase of 7.3p in just seven days.
The average cost of filling a typical 55-litre family car exceeded £100 for the first time on Wednesday.
The average price of a litre of diesel on Thursday was also a record, at 188.8p.
AA president Edmund King said: “This is the worst week of pump pain so far for drivers.
“We would urge drivers at the moment to cut out shorter car journeys if they are able to do so, and walk or cycle to save money.
“Almost one fifth of AA members are already doing this.
“But by changing your driving style you can also save up to 15% on fuel costs.
“These crippling fuel costs are hitting home so drivers need to take all the steps they can to stay mobile.”
The AA claimed high streets are losing out on £23 million a day in “potential consumer spending” as that is the estimated extra amount drivers are spending on petrol compared with this time last year.
RAC fuel spokesman Simon Williams said it is “becoming clearer by the day that the Government must take further action to reduce the enormous financial burden on drivers”.
He accused the Government of being “fixated on ensuring retailers are passing on March’s 5p duty cut fully”, claiming this is “ignoring the fact that wholesale costs of fuel have absolutely rocketed since then”.
Mr Williams added: “A temporary cut in VAT on fuel, or a deeper duty cut, are surely what is needed now.”
Asked about the issue on Thursday, Prime Minister Boris Johnson said: “We made a cut already… the biggest cut ever in fuel duty.
“What I want to see is those cuts in taxation not just swallowed up in one gulp, without touching the gullet of the fuel companies, I want to see those cuts having an impact on the pumps.
“And we are watching very closely to see what happens.”