Transportation and Traffic Engineering Flashcards
7 cards from real Civil Engineering PE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Transportation and Traffic Engineering flashcards as text
A freeway weaving section has a weaving volume of 1,200 vph and a non-weaving volume of 3,000 vph. The volume ratio (VR) used in HCM weaving analysis is:
Answer: 0.286
VR = weaving volume / total volume = 1,200/(1,200+3,000) = 1,200/4,200 ≈ 0.286.
A highway curve has a posted advisory speed of 35 mph. A truck with a center of gravity height of 6 ft and track width of 8 ft negotiates the curve. The rollover threshold lateral acceleration is:
Answer: 0.67g
Rollover threshold = track width/(2 × CG height) = 8/(2×6) = 0.667g ≈ 0.67g.
The MUTCD requires that a 'School Speed Limit' sign be used only when the speed limit applies during specific times. Which beacon type is typically used with school speed limit assemblies?
Answer: Flashing yellow LED beacon
MUTCD recommends flashing yellow LED beacons with school speed limit signs to alert drivers when the reduced speed is in effect.
The AASHTO flexible pavement design uses the Structural Number (SN). If layer coefficients are a1=0.44, a2=0.14, a3=0.11, drainage coefficients m2=m3=1.0, and layer thicknesses D1=4 in, D2=6 in, D3=8 in, the SN is:
Answer: 3.48
SN = a1D1 + a2D2m2 + a3D3m3 = 0.44×4 + 0.14×6×1.0 + 0.11×8×1.0 = 1.76 + 0.84 + 0.88 = 3.48.
Speed studies on a road yield the following 85th percentile speed: 52 mph. The posted limit is 45 mph. Based on the 85th percentile rule, the engineer would recommend:
Answer: Raising the speed limit to 50 mph
The 85th percentile rule suggests setting the speed limit near the 85th percentile speed; 52 mph rounds to 50 mph per standard practice.
A pedestrian crossing has a walk phase of 7 s and a pedestrian clearance interval of 20 s. The crossing width is 60 ft. The minimum pedestrian clearance time required by MUTCD for a walking speed of 3.5 ft/s is:
Answer: 17.1 s
Minimum clearance time = crossing width / walking speed = 60/3.5 = 17.1 s, which must be provided as pedestrian clearance interval.
In the four-step travel demand model, the step that converts trip productions and attractions into origin-destination trip interchanges between zones is called:
Answer: Trip distribution
Trip distribution (Step 2) pairs the productions and attractions from different zones into origin-destination trip tables using models like the gravity model.