Possibly, but if an overpass is built for the trail, they'll also need a fence. More than a few will want to avoid the climb and take the shortcut across the road.

I wonder if this spot can benefit from a simple solution that's common in Mexico.

Mexicans are well aware of how hard it is to control people, so they use the cheap and effective method of speed bumps and humps before busy intersections, especially busy pedestrian crossings. These effectively slow traffic without stopping it, so drivers are better prepared to stop, and pedestrians have greater margin of error when crossing. It also greatly lowers the consequences when folks miscalculate.