I found this thread many years ago...never have forgotten about it, as it has a great listing of Parclo B4 interchanges (thanks
tradephoric).
The two
British Columbia Parclo interchanges listed are no longer in operation. The first link (Hwy 1 @ Brunette Ave) is now a half-diamond/half-parclo, and the second link (Hwy 1 @ Willingdon Ave) is now a folded diamond (though totally rebuilt, with the loops now in the opposite corners).
The only remaining Parclo B4 interchange in British Columbia, which was not listed, is
Hwy 91 @ Nordel Way, at the south end of the Alex Fraser Bridge. It was
built in 1985 (top right corner of photo), and was
rebuilt in 1997.
The rebuild in 1997 did several interesting things:
* upgraded the SW loop to two lanes, which then required three eastbound lanes over Hwy 91.
* westbound through movement restricted down to one lane (previously two)
* limited westbound capacity required the rebuild of the NW loop to get rid of what would have been an extremely short merge (
old roadbed was visible for a while)
* the left turn for southbound Hwy 91 traffic had to be relocated west, off the bridge, the only remaining place where there was room for a left turn lane
Technically it has been modified twice since:
in 2005, to add an HOV bypass to the northbound on-ramp, and then again very recently to add a left turn light for northbound Hwy 91 traffic.
That actually highlights the incredible capacity of the Parclo B4...it was built 34 years ago, and operated without any signals for 33 of those years. Very impressive stuff.