Kent’s motorways were closed for almost 1,000 hours over a three-month period, as figures reveal the extent of the county's summer of travel misery.

Drivers got stuck in tailbacks caused by crashes, roadworks, broken down vehicles and Operation Stack for almost a third of the summer months.

It comes as highways chiefs admit they have barely – if ever – used costly measures installed with the specific purpose of cutting delays during major incidents.

Scroll down for audio

Figures obtained through a Freedom of Information request reveal that in July, August and September this year, Kent’s motorways were either fully or partially shut for a total of 938 hours.

Parts of the M25 alone were closed for 465 hours, while the M20 was shut for 314 hours, the M2 for 135 hours and the M26 for 24 hours.

Highways England bosses say some of these closures did not have an impact on traffic flow.

But many thousands of motorists found themselves trapped in gridlock for several hours – with certain measures designed specifically to prevent lengthy delays going unused.

A movable barrier installed on the M20 in 2008 at a colossal cost of almost £13 million was used just TWICE before it was removed altogether in 2012.

Highways England paid an additional £600,000 a year to lease the so-called Quick Moveable Barrier, which allowed a mobile contra-flow system to be set up whenever Operation Stack was implemented.

But road chiefs say it was scrapped due to its lack of use.

In addition, emergency gates installed on the M2's central reservation near Faversham in 2010 – costing £275,000 – have NEVER been used.

They were brought in to allow vehicles to be diverted along the other carriageway after incidents which close the 13-mile stretch between Sittingbourne and Faversham for long periods of time.

But Highways England says their use requires lane closures on the other side of the carriageway. The gates would only be used in the event of an incident that closed both sides, such as the huge sinkhole that opened up last February.

The most severe delays are usually caused by serious and fatal crashes, which force police to close the road for hours.

Several accidents over the summer caused parts of the motorway network to be closed down for most of the day, which has a knock-on effect on surrounding roads.

To help speed up investigations and reduce closure times, the government granted Kent Police £159,390 in 2011 to spend on two laser scanners.

The technology saves time by making a 3D image of the whole crash scene, which can then be viewed on a computer screen remotely.

Inspector Martin Stevens from Kent Police’s serious collision investigation unit says the scanners have proved valuable, but it still remains necessary to close crash scenes for long periods.

He said: "When investigating an incident on the road network it is often necessary to close the road for an extended period of time.

"We always work to re-open roads as quickly as possible, but it is important to provide a safe working environment for emergency services, and to allow us to fully examine the scene and collate all evidence.

"There will be various tasks at a crash site; full forensic evidence capture, vehicle recovery and road repairs to name a few.

"We have a duty to victims and their families to carry out a thorough investigation and provide them with answers, which does on occasions require road closures."

One group to suffer severely from the impact of motorway closures is the freight industry, which lost millions during the chaos caused by Operation Stack over the summer.

The Freight Transport Association says most of the delays can be prevented if drivers play their part in avoiding crashes and breakdowns.

Natalie Chapman, the FTA’s head of policy for London and the south east, says: "Something very small like a tyre blow out can have a really big impact when you have to start closing lanes or have full closures of the motorway.

"Making sure that we're fit to drive, that our vehicle is roadworthy, that our tyre pressure is correct, we have enough tread on our tyres, and we have enough fuel to complete our journey before setting off would make a difference.

"Making sure that we prevent these incidents is hugely important so we can keep our motorways flowing, because they are the lifeblood of the UK."

Highways England spokesman Jane Kelly said: "Highways England is committed to keeping as many lanes open across its network as possible and reduce the impact caused by incidents.

"Our traffic officers work hard around the clock to clear incidents as quickly as possible, from collecting debris to dealing with serious collisions."