Civil Engineering PE Transportation and Traffic Engineering 4

Question 1

A roundabout entry has a flow of 400 vph and circulating flow of 600 vph. Using FHWA capacity formula (entry capacity ≈ 1,130 − 0.7 × circulating flow), the entry capacity is closest to:

Accepted Answer

710 vph

Answer

840 vph

Answer

530 vph

Answer

900 vph

Question 2

The Equivalent Single Axle Load (ESAL) for a tandem axle group weighing 34,000 lb using the AASHTO Load Equivalency Factor (LEF) tables is approximately:

Accepted Answer

1.11

Answer

2.44

Answer

0.62

Answer

3.27

Question 3

The traffic intensity (ρ) in a D/D/1 queuing model where arrival rate λ = 800 veh/h and service rate μ = 1,000 veh/h is:

Accepted Answer

0.80

Answer

1.25

Answer

0.50

Answer

1.00

Question 4

The minimum passing sight distance (PSD) for a design speed of 55 mph on a two-lane highway per AASHTO is approximately:

Accepted Answer

1,500 ft

Answer

1,000 ft

Answer

800 ft

Answer

2,000 ft

Question 5

A signal timing plan uses Webster's optimum cycle length formula: Co = (1.5L + 5)/(1 − Y), where L = 10 s lost time and Y = 0.75. The optimum cycle length is:

Accepted Answer

70 s

Answer

80 s

Answer

60 s

Answer

90 s

Question 6

In a transportation study, the gravity model for trip distribution is used to estimate trips between zones. If production zone i has 500 trips, attraction zone j has 1,000 attractions, and the friction factor Fij = 2, the trips from i to j (before balancing) with one competing zone k (Ak=800, Fik=4) is:

Accepted Answer

227

Answer

333

Answer

167

Answer

417

Question 7

The design of a left-turn bay requires a storage length based on the number of vehicles expected per cycle. If a cycle is 90 s, the arrival rate is 120 vph, and average vehicle length + spacing is 25 ft, the required storage length is:

Accepted Answer

75 ft

Answer

100 ft

Answer

50 ft

Answer

125 ft