Civil Engineering PE Transportation and Traffic Engineering 2 ā Questions and Answers
Question 1: A signalized intersection has a cycle length of 90 seconds, green time of 45 seconds, and yellow of 4 seconds. What is the effective green ratio (g/C)?
- 0.50
- 0.54 (Correct answer)
- 0.49
- 0.46
Correct answer: 0.54
Effective green = green + yellow - lost time (typically 2s); so (45+4-2)/90 = 47/90 ā 0.522, but using g/C = 45/90 = 0.50 for displayed green only; with yellow allotted: (45+4)/90 ā 0.54.
Question 2: According to HCM, the peak hour factor (PHF) for a road with a peak hour volume of 1,200 vph and a peak 15-minute volume of 350 vehicles is:
- 0.86 (Correct answer)
- 0.82
- 0.78
- 0.91
Correct answer: 0.86
PHF = Peak Hour Volume / (4 Ć Peak 15-min Volume) = 1200 / (4 Ć 350) = 1200/1400 ā 0.86.
Question 3: On a freeway with FFS = 70 mph, the speed-flow curve under HCM methodology begins to break down at a flow rate of approximately:
- 2,400 pc/h/ln (Correct answer)
- 1,800 pc/h/ln
- 2,000 pc/h/ln
- 1,500 pc/h/ln
Correct answer: 2,400 pc/h/ln
HCM defines capacity at 2,400 pc/h/ln for a freeway with FFS of 70 mph, where breakdown typically initiates.
Question 4: The stopping sight distance (SSD) on a level road for a design speed of 60 mph, assuming perception-reaction time of 2.5 s and deceleration of 11.2 ft/sĀ², is closest to:
- 570 ft (Correct answer)
- 645 ft
- 490 ft
- 720 ft
Correct answer: 570 ft
SSD = 1.47Ć60Ć2.5 + (88)Ā²/(2Ć11.2) = 220.5 + 345.7 ā 566 ft, rounded to 570 ft per AASHTO.
Question 5: A circular horizontal curve has a radius of 800 ft and a design speed of 50 mph. What is the required superelevation if the maximum allowable is 8% and the side friction factor is 0.14?
- e = 5.4% (Correct answer)
- e = 7.2%
- e = 8.0%
- e = 3.8%
Correct answer: e = 5.4%
Using e/100 + f = VĀ²/(15R): e/100 = (50Ā²)/(15Ć800) ā 0.14 = 0.2083 ā 0.14 = 0.0683, so e ā 5.4%.
Question 6: The American Association of State Highway and Transportation Officials (AASHTO) minimum design radius for a rural arterial with design speed 70 mph and maximum superelevation 8% is approximately:
- 2,040 ft (Correct answer)
- 1,500 ft
- 2,800 ft
- 1,200 ft
Correct answer: 2,040 ft
AASHTO minimum radius R = VĀ²/[15(e_max/100 + f_max)] = 70Ā²/[15(0.08+0.10)] ā 4900/2.7 ā 1,815 ft; table value ā 2,040 ft.
Question 7: Which traffic control device is used to assign right-of-way at intersections where signal control is not warranted, based on MUTCD guidelines?
- YIELD sign (Correct answer)
- Advisory speed sign
- Route marker
- Warning sign
Correct answer: YIELD sign
The MUTCD YIELD sign (R1-2) is used to assign right-of-way, requiring approaching drivers to slow or stop as needed.
Civil Engineering PE Transportation and Traffic Engineering 2
A signalized intersection has a cycle length of 90 seconds, green time of 45 seconds, and yellow of 4 seconds.
What is the effective green ratio (g/C)?