BCE Highway 3 — Questions and Answers
Question 1: On a two-lane highway, passing sight distance must be sufficient for a vehicle to safely pass another vehicle traveling at what assumed speed relative to the passing vehicle?
- Same speed
- 10 mph slower (Correct answer)
- 15 mph slower
- 20 mph slower
Correct answer: 10 mph slower
AASHTO assumes the passed vehicle travels 10 mph below the design speed while the passing vehicle travels at design speed.
Question 2: What is the typical maximum grade allowed on an Interstate highway in flat terrain according to AASHTO Green Book?
- 3% (Correct answer)
- 5%
- 8%
- 10%
Correct answer: 3%
AASHTO limits maximum grade to 3% on Interstates in flat terrain to maintain acceptable level of service for trucks.
Question 3: The equivalent single axle load (ESAL) concept was developed to compare the damaging effect of different axle loads to which standard axle?
- 10,000-lb single axle
- 18,000-lb single axle (Correct answer)
- 22,000-lb tandem axle
- 34,000-lb tandem axle
Correct answer: 18,000-lb single axle
ESAL converts all axle loads to equivalent repetitions of an 18,000-lb (80 kN) single axle load for pavement design purposes.
Question 4: In traffic engineering, the 85th percentile speed is used primarily for which purpose?
- Calculating fuel consumption
- Setting speed limits (Correct answer)
- Estimating accident rates
- Designing interchange geometry
Correct answer: Setting speed limits
The 85th percentile speed reflects the speed at or below which 85% of drivers travel and is a key basis for setting posted speed limits.
Question 5: Which drainage structure is typically used to carry highway runoff water under the roadway from one side to the other?
- Catch basin
- Culvert (Correct answer)
- French drain
- Swale
Correct answer: Culvert
Culverts are enclosed conduits placed beneath embankments to allow stormwater to cross from the upslope to the downslope side of the road.
Question 6: What does the term 'level of service' (LOS) A represent on the Highway Capacity Manual scale?
- Near-capacity operation with unstable flow
- Free-flow speed with low traffic volumes and full driver freedom (Correct answer)
- Forced flow at jam density
- Moderate congestion with reduced speed
Correct answer: Free-flow speed with low traffic volumes and full driver freedom
LOS A represents the best operating condition: free-flow speeds, very low density, and drivers experience virtually no delay.
Question 7: In rigid pavement design, which type of joint prevents differential settlement between adjacent slabs while allowing horizontal movement?
- Contraction joint
- Construction joint
- Expansion joint (Correct answer)
- Longitudinal joint
Correct answer: Expansion joint
Expansion joints provide space for concrete slabs to expand due to temperature increases while dowel bars transfer load and prevent differential vertical movement.
BCE Highway 3
On a two-lane highway, passing sight distance must be sufficient for a vehicle to safely pass another vehicle traveling at what assumed speed relative to the passing vehicle?