The following clarification was printed in the Guardian's Corrections and clarifications column, Tuesday 18 August 2009

Burma, Iceland and Sweden were juxtaposed with Samoa in the article below about a Samoan plan to change to driving on the left. To clarify: the switchover in the first three countries four decades ago was from left to right.

Burma switched sides in 1970, Iceland in 1968 and Sweden in 1967. Now the Pacific island of Samoa wants people to switch from right to left when driving on the road, sparking protests and fears of chaos when the rule change comes in next month.

Samoans have driven on the right side of the road for more than a century, like their neighbours in American Samoa. But the prime minister, Tuilaepa Sailele Malielegaoi, wants to put an end to the import of costly left-hand-drive cars, particularly big American "gas-guzzlers", and to encourage the 250,000 Samoans who live in Australia and New Zealand, where people drive on the left, to send cars home.

A new political party was formed last year to challenge Tuilaepa over the switchover. Some villages have announced that they will refuse to allow any cars in unless they drive on the right, raising the prospect of traffic mayhem when the plan comes into effect on 7 September.

People Against Switching Sides (Pass), an action group, has launched a legal challenge, to be heard by the courts today, claiming the switch is unconstitutional because the government cannot guarantee Samoans' right to life.

"People will die as a result of this,'' said Dr Biopapa Annandale, the group's chairwoman, in a recent interview with the Australian Associated Press.

Car dealers say the move will cripple them. One dealer, who imports Hyundai cars from South Korea, said his annual sale of 250 cars stopped the day it was announced. Samoa's chamber of commerce has predicted financial turmoil, estimating it will cost the economy at least 790m Samoan tala (£196m).