There is a topic discussing the pros and cons of roundabouts. A less common intersection is the Single Point Urban Interchange (SPUI).

This is an intersection that seems to be mostly used on overpasses. What makes this intersection unique is that all of the different exits, on ramps, and crossing road lanes go through the same location, i.e. the "single point".

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When might a SPUI be beneficial, and when might other intersections be better?


1 Answer 1


Often it's a lack of real estate for any other interchange. As the interchange is very narrow compared to a partial cloverleaf.

The other option is then a diamond interchange. The diamond interchange is more economical because it doesn't need a particularly wide bridge (4-6 lanes depending on the traffic of the other road).

The single point interchange also has a large conflict area in the middle which is less safe than putting 2 intersections next to each other.

The one major plus is that left-turning traffic from both off ramps of the Highway can go together. The left turning traffic of the other road can go together if a contra-flowing setup is used.


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