TRANSPORT policy has one of the biggest impacts on daily life, from how you commute to work to the cost of filling up at the petrol station or the cost of a plane ticket.

For Scots voters, many issues are already decided at Holyrood but others - including control over air passenger duty - have yet to be devolved, while some will have a major implications for the whole of Britain.

One of the first, and most contentious, issues to face the new Government at Westminster post-May 7 will be the long-awaited recommendation on whether Heathrow or Gatwick should get an extra runway.

The Airports Commission will issue its final report this summer, nearly three years after it was first tasked considering how the UK could "maintain its status as an international hub". Both airports promise to use their additional run to boost connections from Scotland to London, but Heathrow has attracted the most backing to date including from bodies such as the Scottish Chamber of Commerce.

However, there are those - including BA boss Willie Walsh and Business Secretary Vince Cable - who insist a third runway at Heathrow is too "politically toxic" to ever get the go ahead, regardless of the Commission's recommendations.

Another big decision which Scotland has a disproportionate stake in is the location of the UK's first spaceport. Three Scottish sites - Campbeltown, Glasgow Prestwick, and Stornoway - have been shortlisted as possible permanent bases for the facility, with competition from Newquay and Llanbedr in Wales. A decision is expected later this year with the aim of establishing the spaceport by 2018.

High-speed rail is arguably the most divisive infrastructure project of all, and oddly perhaps the only area where Greens and Ukip concur - in both being dead against it. To the Greens, HS2 will turn the Midlands into a "London commuter suburb"; for Ukip, it is an "EU vanity project" we cannot afford.

The Tories, Labour and LibDems favour extending it as far as Leeds and Manchester with an 'HS3' spur, while the SNP support it - but only if it reaches Glasgow and Edinburgh too.

Conservatives - Have pledged to freeze regulated rail fares at no more than RPI inflation in England for five years, which would affect on cross-Border journeys on the East and West Coast Main Lines.

The are also committed to HS2 and development for an "HS3" Leeds-Manchester line which is projected to shave an hour of Scotland-London travel once complete in 2032. Reform strike laws, including on the transport network.

Labour: The party wants to reform rail franchising to allow a UK-based public sector rail operator to bid for and run franchises.

They have also committed to spending £250 million on cycling infrastructure, safety and integration, and to create a cross-government Cyclist and Pedestrians' Advisory Board to "put cyclists and pedestrians at the top table of transport policy".

Support HS2 but want to keep costs down. Plan to extend London-style transport powers to local authorities in England.

LibDem: One of the few major parties to veto any airport expansion in the south-east - either second runway at Gatwick or third runway at Heathrow. Supporters of expansion believe it is the only way to boost connectivity between Scotland and the capital.

Pledged to introduce subsidised bus passes giving 16-21-year-olds in England a 66 per cent discount on travel

Support more light rail links in towns and cities

SNP: Support high-speed rail but want the planned HS3 line to extend to Glasgow and Edinburgh, with an option to begin building north to south simultaneously.

Also want shake-up of rail franchising process to enable "public sector bids and non-for-profit models" from UK-based operators.

Have urged UK Government to devolve control over Air Passenger Duty to Holyrood as quickly as possible, with plans to halve and eventually scrap the tax on all flights departing from Scotland.

Greens: Pledged to spend £1.5 billion subsidising existing public transport to make fares up to 10 per cent cheaper

Plan to tax aviation industry by introducing fuel duty and VAT on tickets and aircraft to raise around £10bn a year

Allocate at least 10 per cent of transport spending on policies to encourage more walking and cycling, and re-regulate the bus industry

Opposed to HS2

Ukip: Will scrap HS2 and require foreign vehicles to purchase a "Britdisc" before entry to the UK to fund upkeep of UK roads.

They have vowed to maintain pensioner bus passes and ensure that speed cameras are "used as a deterrent and not as a revenue raiser".

Oppose road tolls and will let existing tolls contracts expire

DUP: Supports investment in employment intensive infrastructure projects.

Ensure public transport and car parking issues are fully taken into account in planning determinations.

Supports minimising road casualties through road safety engineering, collision remedial schemes, traffic calming, school safety zones and improved pedestrian and cycle networks

Seek to ensure that the Belfast-Londonderry rail link has commuters arriving before 9am.