Traffic in London. Monday Aug. 7, 2006. According to a leaked document, the government's Transport Secretary is seeking powers to impose toll roads across Britain. The Sunday Times has published a letter from Douglas Alexander claiming such tolls would help cut congestion and improve public transport. (AP Photo/Kirsty Wigglesworth)

Members of the Liberal Democrats political party in the UK (Lib Dems) have put forth a proposal that would see millions of gasoline- and diesel-burning passenger vehicles banned from British roads by 2040. As one pillar of its plan to create a "zero carbon" country, the proposed policy would see only "ultra-low carbon vehicles" – essentially super-efficient hybrids and electric vehicles – allowed for general use on public roads. Gasoline- and diesel-powered vehicles would still be permissible for hauling freight, however. For the record, such a proposal is not a brand new idea for the party.

The plans are certainly a long way from law at this point, however. The proposal is set to be voted on by Lib Dems at an upcoming party conference in Glasgow. If adopted, the plan would become part of the party's own policy, but not the law of the land.

Other items up for debate, and pursuant to the zero-carbon goals, include: an air passenger duty with trip-based carbon consumption charges, road-use tolls in congested areas and expansion of nuclear power and shale gas exploration.

According to the report in The Telegraph, Lib Dems are interested in the cost-saving potential of shale exploration, as long as "regulations controlling pollution and protecting local environmental quality are strictly enforced, planning decisions remain with local authorities and local communities are fully consulted over extraction and fully compensated for all damage to the local landscape."