In the last month, hundreds have drivers have been stuck in seemingly unexplainable gridlock on the A338. 

There have been very few accidents and breakdowns in the roadworks area - Dorset County Council says they've dealt three collisions and seven breakdowns, plus three vehicles going the wrong way down the contraflow system.

So why have so many of us been caught in pockets of gridlock, particularly northbound, when there's no reason for the traffic not to carry on flowing freely? 

It's the curse of the phantom traffic jam (also known as the jamiton), where one driver braking too hard causes a wave of braking in the traffic behind. The further back from the first driver you are, the more likely you are to have to stop moving completely and the longer it will take to get moving again.

Dorset County Council has reminded motorists and bikers to take extra care to avoid incidents which could lead to major delays.

Cllr Peter Finney, cabinet member for environment, said: "As a motorcyclist myself, I know it is important for us to be aware of the risks, but also for vehicle drivers to be extra vigilant as well.

"My advice would be to keep your distance and keep a good eye on brake lights ahead.

"Make sure you take all the adequate measures to prevent yourself from rear-ending another vehicle.

"But I would also ask car drivers to be more aware as well.

"The contraflow system does mean the road has narrowed and everyone needs to be aware of this."

On the work completed so far, he added: "It's going well; better than expected.

"These things are always problematic but initial issues have settled and I am very happy with how we are doing."

Dorset County Council's collision reduction team manager Michael Potter said: "I would encourage motorists to drive responsibly at all times, but particularly through these and other essential road works."

This week, night time closures of the A338 will continue, with the northbound carriageway closed tonight - Monday - and Tuesday from 8pm until 6am.