Trail #4 is a motorcycle trail that is a classic ride in the Boise area. It is a sandy and loose trail later in the season, but can be pretty fast in late spring just after it dries up. The trail starts off of 8th St. with a traverse that pops in and out of the trees until you hit the ridge line.
Once on the ridge, the trail drops very steeply in sections and you'll find large water bar and extensive ledges to drop off of. There are a number of sections of whoops from motorcycles that need to be ridden at speed so you don't get bogged down in them. In the middle of the trail there is a section that is called devil's staircase and is composed of a bunch of small ledges. The best of riders will hit this fast and flow down the ledges. Less experienced riders will want to be careful.
This trail sees little traffic, so you can really open it up. Once you hit the sidewinder junction you'll be back in the main foothills and will need to watch your speed.