Black Mountain is a steep mountain grade located in the Appalachian Mountains of North Carolina on Interstate 40. Black Mountain Summit is located approximately 15 miles east of Ashville, North Carolina. This mountain has an aggressive eastbound descent and a moderately aggressive but short westbound descent.
Westbound I-40 Black Mountain Summit has a grade of about 5% for the first mile before flattening to about 1.5% for about the next two miles. Westbound Black Mountain has a total vertical descent of 411 ft. over a distance of 3.3 miles. The calculated average grade for the westbound descent is 2.3%.
Eastbound I-40 at Black Mountain Summit has a mandatory truck stop where signs containing information about the grade are displayed. After stopping, trucks must then weigh at a traffic metering signal before re-entering Interstate 40. Eastbound Black Mountain has a vertical descent of 1,361 ft. over a distance of 4.8 miles. The reported grade for the eastbound descent is 6% for 5 miles. The eastbound descent has three runaway truck ramps, one at 2.7 miles, one at 3.2 miles and one at 3.5 miles east of the summit.
SUMMIT
Pass Name:
Black Mountain
Traversed by Highway:
I-40
Summit Elevation:
2,786 ft
Summit Conditions:
Mandatory truck stop with metering traffic signal and information signs for eastbound descent
Summit Milepost:
67.3
WESTBOUND DESCENT
Base Elevation:
2,375 ft
Vertical Distance:
411 ft
Base Milepost:
64
Driving Distance:
3.3 miles
Posted Speed Limit:
65 mph
Calculated Average Grade:
2.3%
Number of Lanes:
Three westbound, Three eastbound
ELEVATIONS
Mile Marker
Elevation
Change in Elevation
Percent Grade
67.3
2,786 ft.
67
2,785 ft.
1 ft.
.06%
66
2,523 ft.
262 ft.
4.9%
65
2,435 ft.
88 ft.
1.6%
64
2,375 ft.
60 ft.
1.1%
EASTBOUND DESCENT
Base Elevation:
1,425 ft
Vertical Distance:
1,361 ft
Base Milepost:
72.1
Driving Distance:
4.8 miles
Posted Speed Limit:
55 mph/ 35 mph for trucks
Steepest Reported Grade:
6% for 5 miles
Calculated Average Grade:
5.3%
Number of Lanes:
Three eastbound, Three westbound
Runaway Ramps:
One at 2.7 miles from summit
One at 3.2 miles from summit
One at 3.5 miles from summit
ELEVATIONS
Mile Marker
Elevation
Change in Elevation
Percent Grade
67.3
2,786 ft.
68
2,578 ft.
208 ft.
3.9%
69
2,286 ft.
292 ft.
5.5%
70
1,981 ft.
305 ft.
5.7%
71
1,682 ft.
299 ft.
5.6%
72
1,445 ft.
237 ft.
4.4%
72.1
1,425 ft.
20 ft.
3.7%
RECOMMENDED SPEEDS FROM THE GRADE SEVERITY RATING SYSTEM
MAXIMUM TRUCK WEIGHT (POUNDS)
MAXIMUM SAFE SPEED (MPH)
BRAKE TEMP FROM DECLINE (°F)
BRAKE TEMP FROM EMERGENCY STOP (°F)
TOTAL BRAKE TEMP. (°F)
TOTAL TRAVEL TIME (MIN.)
80,000
30
451
22
473
9.6
75,000
35
461
28
489
8.2
*These speeds are based on an average grade from the summit to the base. Some grade segments may be steeper than the average and require a slower speed.
