GLASGOW has been listed as one of the world's 100 most congested cities, with rush-hour motorists facing worse gridlock than drivers in Las Vegas.

The global breakdown, which names Istanbul in Turkey as the world's most congested city, is based on traffic data from 2014 collated by the satnav manufacturer, TomTom.

It reveals that drivers in Scotland's largest city face an increase to their journey times of nearly 50 per cent during the morning and evening peaks, compared to periods where the traffic is free flowing, such as during the night.

Glasgow was ranked 91st in the table, immediately above Las Vegas and also ahead of other major cities included Madrid, Abu Dhabi and Detroit.

However, when the table is reset to include all city sizes - not just the default setting of cities with populations of 800,000 or more - Edinburgh outstrips Glasgow for congestion.

In the all-size city list, Edinburgh is ranked as the third most gridlocked city in the whole of the UK, exceeded only by Belfast and London.

Commuters in Edinburgh, which has a population of less than half a million, actually face worse rush-hour evening delays than commuters in London according to the TomTom data.

The satnav manufacturer has calculated that a motorist with a 30 minute daily commute in the Scottish capital will rack up a total of 93 hours a year stuck in traffic, compared to 92 hours for a London commuter and 74 hours for Glasgow drivers, and 57 hours for Sin City's motorists.

The Traffic Index report published today [Tuesday] is the fifth analysis of congestion worldwide by the satnav company.

Overall it shows that traffic flow in most UK cities, including Edinburgh and Glasgow, worsened in 2014 compared to the previous year.

Neil Greig, the Scotland-based director of policy for the Institute of Advanced Motorists, said: "The fact that Edinburgh is worse than Glasgow for congestion won't come as a surprise to motorists - it takes much longer to get around Edinburgh than Glasgow.

"But I am surprised that Glasgow is worse than so many big American cities because the road design is quite American-like in some ways, with more motorways and bigger roads through the city.

"The fact that congestion is getting worse in both cities is to be expected because we're seeing more people using their cars again. It's a sign of the economy recovering and maybe also the fall in fuel prices.

"Glasgow and Edinburgh councils maybe had a couple of years there where they thought they were getting on top of the problem, but now it's returning.

"The solution is better public transport."

Lesley Hinds, transport convener at Edinburgh City Council, said: "We are committed to reducing congestion for those who visit, work and live in the city, and have a number of initiatives and operations in place to help achieve this. One of our main objectives is to facilitate an integrated public transport network, encouraging use and reducing the number of journeys people make by car, particularly during rush hour."

The council was spending more on cycle infrastructure and the launch of the trams had seen the number of people using council-run public transport, including Lothian buses, surge by 100,000 in 2014, she added.

A spokeswoman for Glasgow City Council said they were working to reduce congestion by increasing the proportion of journeys made by public transport, bike and on foot.

She added: "Although it is recognised that congestion is an issue on certain streets at certain times of the day, particularly during the evening peak, traffic data over the last two years show there has been a 4 per cent decrease in cars entering and leaving the city centre."