My interchange designs.

dubhthach

Enbee wrote: »

The M50 interchanges were clearly inadequate for the medium term even when they were under construction. Even the airport exit from the M1 was needlessly constructed as a roundabout even though according to earlier plans it was going to be a trumpet. (Granted, the Gatwick exit on the M23 is also bizarrely a roundabout.) The Northern Cross section of the M50 repeated the errors and now we have the absurdity that is the M1-M50 interchange.

The M50 was initially designed with proper fully grade seperated junctions in mind, some time in the mid-80's it was decided that if they used round abouts they would save IR£50 million on the entire project.

murphaph

The airport M1 spur is almost certainly a roundabout because the council expects to open up the land immediately east of it for some sort of development. The roundabout cost more to build than a trumpet would have (2 bridges instead of one, traffic lights instead of none) so cost was clearly not the deciding factor there.

mysterious

The Tipp interchange layout.
Sorry for the quality.

Chris_533976

I'd be wary about that one. Traffic coming from the bottom of the pic and wanting to turn right could very easily block traffic wanting to go left. Unless the entire slip is 2 lane though.