Black Bear Road is a notorious jeep trail that starts from 11,018-foot (3,358 m) summit of Red Mountain Pass on U.S. Highway 550 (between Ouray and Silverton) to Telluride, Colorado.
The Black Bear Road crests at Black Bear Pass, elevation 12,840 feet (3,910 m). The road descends over a set of infamous switchbacks as it navigates the heights above Telluride. The road passes Bridal Veil Falls, the highest waterfall in Colorado. The road was made famous in a spoken word song by C.W. McCall of the same name.
The road is one way going into Telluride except for once a year when there is a special trail ride out of Telluride. The trail is right next to Bridal Vail Falls which is the site of one of the early Westinghouse / Tesla A/C generating plants that supplied power to the Smuggler Union Mine. 
The trail off of 550 is a regular rock bottom road until you end up on a narrow ledge just wide enough for a Hummer or about 8 feet wide. The right side is a vertical cliff wall and the left is a 1000 foot or more drop. This section curves around to the right. and comes out to a series of very tight switchbacks. 2 or 3 of the switchbacks took about 100 turns (just kidding) to get through with spotters. There is a good amount of 'pucker factor' because the edge of each switchback is a shear major drop. Once you get past the first 3 switchbacks the drive down is a cakewalk.
Black Bear Road is open a few months of the year, from late summer (usually the last week of July) to early fall. The road is traveled only downhill from Red Mountain Pass—except for the annual Jeeper's Jamboree in which travel is reversed for one day only. 
The start of the trail is marked along U.S. 550 with the famous sign that reads:
TELLURIDE ——> CITY OF GOLD. 12 MILES - 2 HOURS
YOU DON'T HAVE TO BE CRAZY TO DRIVE THIS ROAD - BUT IT HELPS
JEEPS ONLY
but the sign was often stolen and eventually the responsible authorities ceased to replace it.
Black Bear Road is a difficult, dangerous trail even for four-wheel drive vehicles. Most of the guide books on the area rate this trip as extremely difficult, and not for the novice. If you decide to take a trip over the BBR, check with the locals for current conditions. Make sure that you obtain a good topographical map to help in navigating the back country.
Though Black Bear Pass road is in places exceedingly steep and narrow, especially in a pitched rock section above Ingram Falls referred to as "The Stairs”. If you have to be rescued, expect a towing bill in four figures. In 1975 two New Jerseyans successfully completed the entire 4 wheel drive road from Red Mountain Pass to Telluride following this route while driving a 1970 Ford F-250 full size 2-wheel drive pickup. In order to negotiate the tight switchback curves, they had to resort to backing down every other switchback. This technique is not recommended.
In 2004 a jeep slipped off the slope near the beginning of the switchbacks and fell several thousand feet, killing two of the passengers and severely injuring two others. Related article here (http://www.dangerousroads.org/news/176-rollover-claims-two-lives-.html). Guided tours are available.
