Original question written by FE Exam AI Prep from the public FE Civil exam specification. Before release, a solver model re-derived the answer twice from the question alone, without its answer key, and a critic model checked the result, and the arithmetic was re-run as an executable calculation. No licensed engineer reviews these questions. It is not an NCEES question and does not come from any NCEES practice exam. FE Exam AI Prep is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCEES.
Traffic Flow Rate from Vehicle Counts: FE Civil practice problem 5
For the Silver Junction concrete-lined channel, a resident engineer preparing an independent calculation check records 490 vehicles during a 10-min count interval. What equivalent hourly flow rate is obtained?
- A1986.5 veh/hr
- B2305.2 veh/hr
- C2940.0 veh/hr
- D2662.0 veh/hr
Show the answer and worked solution
Answer: C — 2940.0 veh/hr
Worked solution
- Step 1. Convert count interval to hours
10 min = 10/60 hr = 1/6 hr
- Step 2. Compute hourly flow
q = count/time
q = 490 / (1/6 hr) = 490 x 6 = 2940 veh/hr
Why the other choices are wrong
- Choice A
- This figure comes in about twenty-two percent under the count divided by the correctly converted interval, an offset too irregular to match a single obvious miscalculation. Multiplying the vehicle count by 6, the same as dividing by 1/6 hr, gives the verified rate of 2940 veh/hr.
- Choice B
- This figure is about forty-five percent higher than the count divided by the correctly converted interval, a gap too large to trace to one ordinary miscalculation. Multiplying the vehicle count by 6, the same as dividing by 1/6 hr, gives the verified rate of 2940 veh/hr.
- Choice D
- This figure exceeds the count divided by the correctly converted interval by roughly eighteen percent, an offset too irregular to match a single obvious miscalculation. Multiplying the vehicle count by 6, the same as dividing by 1/6 hr, gives the verified rate of 2940 veh/hr.