Huh. I never knew that. What's the (unsigned) highway number for this? I've heard that I-11 would've had three options for extending into the Valley; this Sheep Mountain Parkway looks like remains of the westernmost corridor. As for the east, isn't Hollywood Boulevard currently being built? There are a ton of mountains there, forming the eastern boundary of the Las Vegas Valley landform. Wouldn't that, plus the possibility of running into Lake Mead NRA run prevent anything major from being built there?