NCEES Civil Engineering PE Exam 1 — Questions and Answers
Question 1: The AASHTO flexible pavement design method uses which primary design parameter to characterize pavement structural capacity?
- Resilient modulus (Mr) of the subgrade only
- Structural number (SN) based on equivalent single axle loads (ESALs) (Correct answer)
- California Bearing Ratio (CBR) of the base course
- Pavement condition index (PCI)
Correct answer: Structural number (SN) based on equivalent single axle loads (ESALs)
The AASHTO method characterizes flexible pavement capacity using the structural number (SN), which accounts for layer materials and thicknesses, and is designed for the cumulative traffic load expressed as ESALs.
Question 2: In traffic engineering, the Peak Hour Factor (PHF) is calculated as:
- Total daily volume divided by the peak hour volume
- Peak hour volume divided by four times the peak 15-minute volume (Correct answer)
- Peak 15-minute volume multiplied by four
- Peak hour volume divided by the average hourly volume
Correct answer: Peak hour volume divided by four times the peak 15-minute volume
PHF = (Peak Hour Volume) / (4 × Peak 15-Minute Volume), measuring the uniformity of traffic flow within the peak hour; a PHF of 1.0 indicates perfectly uniform flow.
Question 3: Stopping Sight Distance (SSD) on a highway is composed of which two distance components?
- Reaction distance and curve length
- Perception-reaction distance and braking distance (Correct answer)
- Passing distance and maneuver distance
- Vertical curve length and horizontal clearance
Correct answer: Perception-reaction distance and braking distance
SSD equals the distance traveled during the driver's perception-reaction time (typically 2.5 s per AASHTO) plus the distance required to brake to a complete stop.
Question 4: Using the arc definition, what is the degree of curve for a horizontal curve with a radius of 1,500 ft?
- 1.91°
- 3.82° (Correct answer)
- 2.86°
- 5.73°
Correct answer: 3.82°
Using the arc definition: D = 5729.58 / R = 5729.58 / 1500 ≈ 3.82°.
Question 5: According to the Highway Capacity Manual (HCM), Level of Service (LOS) for a basic freeway segment is primarily defined by:
- Volume-to-capacity (v/c) ratio
- Density in passenger cars per mile per lane (pc/mi/ln) (Correct answer)
- Average travel speed only
- Number of lane changes per mile
Correct answer: Density in passenger cars per mile per lane (pc/mi/ln)
The HCM defines LOS for basic freeway segments by density (pc/mi/ln), with LOS A through F corresponding to progressively higher densities and deteriorating operating conditions.
Question 6: The Marshall mix design method evaluates asphalt concrete using which two primary measured parameters?
- Resilient modulus and creep compliance
- Marshall stability and flow (Correct answer)
- Hveem stability value and air voids
- Dynamic modulus and phase angle
Correct answer: Marshall stability and flow
The Marshall method measures stability (maximum load resistance at 60°C) and flow (deformation at maximum load) to select the optimum asphalt binder content for the mix.
Question 7: Superelevation runoff on a horizontal curve is defined as the length of roadway required to transition the outside lane cross slope from:
- Normal crown to full superelevation
- Flat (0%) to full superelevation (Correct answer)
- Full superelevation back to normal crown
- Adverse cross-slope to flat (0%)
Correct answer: Flat (0%) to full superelevation
Superelevation runoff is the distance needed to rotate the outside lane from 0% (flat) to the full design superelevation rate; tangent runout is the separate length that removes the adverse normal crown.
NCEES Civil Engineering PE Exam 1
The AASHTO flexible pavement design method uses which primary design parameter to characterize pavement structural capacity?