Tuesday, April 20, 2010

Single-point interchange

One of the better designs for a freeway interchange with an arterial road is the single-point interchange (SPI). An SPI uses less land and is safer as it reduces conflict points. The following two pictures show the older style cloverleaf and the new SPI.

The Langley 200th Street interchange is the perfect example of a SPI and shows its efficiencies. 200th Street was widened from 2 lanes to 6 lanes and actually now uses less space. In fact where the old interchange was, they are now putting in major developments. This leads me to believe that there is lots of wasted land because of the inefficient cloverleaf and freeway design in our region. The following pictures prove this point.

200th Street in Langley

Inside the former 200th Street cloverleaf

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