Take a quick look at Google Maps and you'll see I-15 is a very short distance away. It's not like they decided to go full San Francisco and run major six-lane highway routes at surface level. The people using this sort of route are probably all locals. All of the through traffic is already on the freeway.
Freeways divide neighborhoods; we can't plop them down everywhere, and definitely not in this situation. It takes a massive amount of room to move vehicles at a rapid rate, and it discourages pedestrian-friendly, dense land use (then again, it looks like they already made that decision with a bunch of single-family house subdivisions). Notice nearby that the stuff you can access from I-15 is a bunch of big roads, malls, car dealerships, and an Air Force base. Nobody really likes living next to it, either: there's measurably worse air pollution and much higher noise.
Plus, as we see in any majorly dense area, the freeways turn into buffers for inadequate local traffic capacity as they very quickly turn into parking lots. Low volume exits onto slow surface streets with tons of intersections jams everything up.
Freeways divide neighborhoods; we can't plop them down everywhere, and definitely not in this situation. It takes a massive amount of room to move vehicles at a rapid rate, and it discourages pedestrian-friendly, dense land use (then again, it looks like they already made that decision with a bunch of single-family house subdivisions). Notice nearby that the stuff you can access from I-15 is a bunch of big roads, malls, car dealerships, and an Air Force base. Nobody really likes living next to it, either: there's measurably worse air pollution and much higher noise.
Plus, as we see in any majorly dense area, the freeways turn into buffers for inadequate local traffic capacity as they very quickly turn into parking lots. Low volume exits onto slow surface streets with tons of intersections jams everything up.