Peers have approved new powers which would see car owners fined if anyone drops rubbish out of their vehicle.
The new law has been hailed as a means to tackle "thoughtless" anti-social behaviour.
Under the measure, the registered owner of a vehicle would face a penalty for littering, even if they did not carry out the act themselves.
Currently a criminal penalty only applies to the person responsible, something Tory backbench peer and supporter Lord Marlesford argued is often hard to prove.
RAC spokesman Simon Williams said: "While the RAC sees any environmental legislation that helps reduce litter and improve the appearance of our roads and countryside as a good idea, ensuring that passengers do not drop litter out of the window for fear of being fined may cause an unnecessary distraction for drivers and therefore could have a negative effect on road safety."
In amendment at the third reading of the Anti-social Behaviour, Crime and Policing Bill, Home Office minister Lord Taylor of Holbeach said: "These (new) powers are intended to make life easier for local authorities."
He further praised Lord Marlesford for persuading the Government to adopt the proposals, saying: "All of us in this House share your views about the scourge of litter defacing our roads, towns and countryside.
"This new measure will enable us to give local authorities in England an additional power to tackle this anti-social behaviour."
Home Secretary Theresa May and Environment Secretary Owen Paterson support the new powers, Lord Marlesford said.
Copyright Press Association 2014