Orange County NC Website
Browse       Search
COPY NCDOT <br />a. The maximum grades in percent shall be: <br />Design Speed Level Rolling Mountainous <br />60 3 4 6 <br />50 4 5 7 <br />40 5 6 8 <br />30 9 10 <br />20 12 <br />b. A minimum grade for curbed streets <br />normally should not be less than 0.5 %, a grade <br />of 0.355 may be allowed where there is a high <br />type pavement accurately crowned and in areas <br />where special drainage conditions may control. <br />c. Grades for 100 feet each way from <br />intersections should not exceed 5% <br />d. For streets and roads with projected <br />annual average daily traffic less than 250, <br />short grades less than 500 feet long may be <br />150% greater. <br />3. Minimum Sight Distances <br />In the interest of public safety, no less than <br />the minimum sight distance applicable shall be <br />Provided in every instance. Vertical curves that <br />connect each change in grade shall be provided and <br />calculated using the following parameters. (General <br />practice call for vertical curves to be multiples <br />of 50 feet. Calculated lengths shall be rounded up <br />in each case): <br />Design Speed, MPH <br />Stopping Sight Distance - <br />Min. Distance, Ft. <br />Desirable Distance Ft. <br />Min. K* Value For: <br />20- 30 40 50 60 <br />150 200 275 350 475 <br />150 200 300 450 650 <br />Minimum Crest Curve <br />16 <br />28 <br />55 <br />85 <br />160 <br />Des. Crest Curve <br />16 <br />28 <br />65 <br />145 <br />300 <br />Minimum Sag Curve <br />24 <br />35 <br />55 <br />75 <br />105 <br />Des. Sag Curve <br />24 <br />35 <br />60 <br />100 <br />155 <br />Passing Sight Distance - <br />Minimum Passing Distance, <br />Feet (2 lane) <br />Minimum K* Value for Crest <br />Vertical Curve <br />67 <br />1100 1500 1800 2100 <br />365 686 985 1340 <br />