I see signs on the road that say 6% grade or some other number. What does this mean? I am guessing that it means something like the road drops 6 feet down for every 100 feet of road. Anyone know for sure?
2006-09-25 07:07:05 · 14 answers · asked by Anonymous in Science & Mathematics ➔ Engineering
Drop per run.
You got it correct. A 6% grade is 6 feet up or down for every 100 feet traveled horizontally.
A zero grade has no slope at all and a 10% grade is considered very steep. Old railraods (sream) usually set a limit at about 7.0% grade.
2006-09-25 07:08:46 · answer #1 · answered by Richard 7 · 67⤊ 0⤋
On I-68 approaching Cumberland, MD - there is a 13 mile downhill grade which is marked at 6%. The problem is that there is not a (13*0.06) = 0.78 mile (or 4000 foot) descent between downtown Cumberland and the beginning of the downhill grade (which is the summit of Dan's Mountain at the Garrett/Allegheny line).
MD signs this grade at 6% to make truckers aware of the severe downgrade entering Cumberland because I-68 is substandard due to many twists and turns while passing through town.
While this may have little or no relevance to the question at hand - the sign serves as an advisory for cars and trucks to control their speed (with the transmission rather than brakes) when descending grades. I've hit 100+ rolling downhill in neutral and I did not like that feeling at all....
2006-09-25 10:03:27 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Several of the answers here are not quite correct. The percentage grade is based on the HORIZONTAL distance traveled but is slightly off on a downward grade since you are actually traveling on the hypotenuse of a right triangle. On an 8% grade, the base of this triangle is 100 feet and the leg is 8 feet which would make the hypotenuse about 100.32 feet.
2016-07-08 15:25:49 · answer #3 · answered by Jim 1 · 0⤊ 0⤋
For example, a grade that rises or drops 2 inches for every 100 inches of road is a 2% grade.
2006-09-25 07:11:51 · answer #4 · answered by wcholberg 3 · 0⤊ 0⤋
Yes, that's what it means... Of course it could also mean that the road rises 6 feet for every 100 feet of road too...
2006-09-25 07:09:30 · answer #5 · answered by Andy FF1,2,CrTr,4,5,6,7,8,9,10 5 · 0⤊ 0⤋
According the Oregon Department of Transportation: "A sunken grade occurs when the earth moves slowly under the road and creates a depression in the roadway."
2016-03-27 09:07:49 · answer #6 · answered by Anonymous · 0⤊ 0⤋
You are correct in your description of degrees. The signage is for truck drivers. The grade amounts let truck drivers know what they need to know to safely get that truck up or down that hill. Some commercial traffic is not allowed over 8 % due to basic truck weight and the addition of load weight and the effects of gravity on the truck and the ability to stop. Ever notice a runaway ramp for trucks?? They are usually in places over 6% grade for long stretches of road in case the driver burns his brakes if he isnt using them correctly.
2006-09-25 07:45:06 · answer #7 · answered by MsDebi 2 · 0⤊ 0⤋
Yes, exactly. The % grade is the drop or increase in altitude in feet, per hundred feet traveled. This is equivalent to the tangent of the grade angle. (% grade can also be given as sine, but tangent is more intuitive and more commonly encountered.)
2006-09-25 07:08:35 · answer #8 · answered by DavidK93 7 · 1⤊ 0⤋
How much the road elevation increases or decreases every one hundred feet
2006-09-25 07:11:14 · answer #9 · answered by iron03triathlete 1 · 0⤊ 0⤋
it's the angle of the slope of the road, the steeper the slope the more % grade there is. means drive with caution, and make sure your brakes are working properly
2006-09-25 07:10:30 · answer #10 · answered by rimples25 3 · 0⤊ 0⤋
It is the degree at which the road is slanted at.
2006-09-25 07:09:22 · answer #11 · answered by Anonymous · 0⤊ 0⤋