Monday, November 03, 2008

Unsticking a jam?

Anyone who is a driver will probably have had the joy of being stuck in an almight tailback on the motorway caused by a breakdown or accident miles ahead. The kind of incident hat makes you shunt forward and occassionally stop the engine for fear of overheating.

Something that occured to me last night (as I drive past a tailback on the other carriageway) was why do we not build special "U-Turn junctions" between the junctions that are opened in the event of emergencies to divert traffic up the other carriageway to seek alternative routes?

10 comments:

IanVisits said...

U-turn if you want to - the lady driver's not for turning.

scallywag said...

Far too sensible...

Anonymous said...

you'd have trouble in both directions then.

Anonymous said...

What? Miss an oppotunity to maximise any inconvenience to the motorist? Get real.

Alan Douglas said...

Dizzy, in the UK cars are considered to be DANGEROUS. IF we have to have dedicated car roads (motorways) we must isolate them from the normal roads.

In Germany it is quite easy to slip down the side of an Autobahn to get onto field tracks, then minor roads and to the road network, for exactly the reason you suggest.

In the UK you have thousands of miles of armco specifically to keep those dangerous cars penned in.

On a related matter, there used to be a time when the law, arriving at the scene of an accident, would do its best to minimise the inconvenience to all other road users and help direct traffic alternatively round the spot. Now, they deliberately seal off the whole road or motorway, thus ensuring that sometimes many miles around are affected with displaced traffic.

I guess that would be for Elf and Safety ? So one spot is made safer by displacing the dangers to many more spots, which are probably not designed to handle such traffic flows. Where is the safety in that ?

Alan Douglas

Anonymous said...

Oooh, Oooh, I know this one.

It's because none of our politicians drive and they all regard drivers as lower than criminals.

Did I get it right???? Did I??

James D said...

This is the corollary of not building enough minor junctions (see M50 J3 for a perfect example). Sometimes design standards just have to give. But just try explaining that to a traffic engineer...

Alan Douglas said...

James D :

I used to have a similar opinion, until someone pointed me at the road systems of one of the Gulf States, which apparently were superb, and designed by British engineers. In the UK, they design to the specs thay are given, by ummm, errrr, oh yes, national and local government bureaucrats.

Alan Douglas

Lola said...

...and how about a 'turn off the traffic lights' day in every toen accross the UK? You'd be surprised at how effeciently we can all sort it out without fascist sharing by bureaucrats. (Keep pedestrian lights heer and there tho')

Alex said...

I think you will find they would rather keep the traffic parked on the motorway than finding alternative routes which just bungs up every other road.

If you assume you have 3 lanes of traffic held up between junctions [n] and [n+1], and most of those cars want to go beyond [n+1], then they all have to go back to junnction [n] on the other carriageway and find their way back to junction [n+1] on minor roads. There probably wouldn't be enough capacity capacity on those roads, so the queues would tail back on to the motorway as far as the U-turn thinggy, with both side of the motorway clogged up.

Which would then mean they would have to open up the U-turn from the other direction, and pretty soon you would have as many people travelling in the direction they didn't want to go as were travelling in the direction they did want to go.