NICET - Highway Construction Inspection Practice Exam

If a road has a grade of 2% with an elevation of 1252 at station 450+20, what will be the elevation at station 455+30?

1. 1257.2

2. 1262.0

3. 1262.2

4. 1270.0

The correct answer is: 1262.2

To determine the elevation at station 455+30 given a 2% grade starting from an elevation of 1252 at station 450+20, it is important to understand how the grade percentage translates to the rise in elevation over a distance. A grade of 2% means that for every 100 horizontal units of distance, the elevation changes by 2 units. First, calculate the horizontal distance between the two stations. The station numbers translate to the following distances: - Station 450+20 is equivalent to 45020 feet. - Station 455+30 is equivalent to 45530 feet. The difference in distance is: 45530 - 45020 = 510 feet. Next, since the road has a 2% grade, the elevation change can be calculated as: Elevation change = (Grade × Horizontal distance)/100 Elevation change = (2 × 510)/100 = 10.2 feet. Now, add the elevation change to the starting elevation: Ending elevation = Starting elevation + Elevation change Ending elevation = 1252 + 10.2 = 1262.2 feet. This calculation gives us the correct elevation at station 455+30, which is 1262.2