...shows the fallacy of building another highway
(Legacy) WEST of I-15, rather than just widening I-15 and building more exits -- as well as building an east-side "collector" system that could be converted to a two-way road in case of such emergencies.

Remember the tanker fire that closed I-15 in Bountiful for hours, a few years ago? Residents were angry that Legacy's construction had been halted "because we could have used it now". Well....not really.

In case of emergency, especially an earthquake, it will be difficult to pass under I-15 to get to Legacy.

UDOT redo 500 South interchange in Bountiful for I-15 as well as being an exit/on-ramp connector to Legacy.

The fatal flaw in the Legacy highway is that there's no way to get from northbound I-15 to Northbound Legacy until you get to 500 south in Bountiful. And even if there's an I-15 closure further north, you're never going to get a whole freeway's worth of cars from I-15 to Legacy going along 5th south -- it's just too small of a road.

There needs to be a way to get from I-15 northbound to 215 west/south, which would allow you to use Legacy or Redwood.

Legacy is great for lightening the load on I-15 during normal times, but as soon as there's a wreck, it does no good for the majority of people that will still be stuck on the freeway.