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, Speed and Density: FE Civil practice problem 2
For the East Valley airport access road, a project engineer preparing a capacity verification worksheet uses the traffic stream relation with speed 40 mph and density 33 veh/mi. What flow rate is indicated?
- A917 veh/hr
- B1320 veh/hr
- C1005 veh/hr
- D1157 veh/hr
Show the answer and worked solution
Answer: B — 1320 veh/hr
Worked solution
- Step 1. Use traffic flow relation
q = k v
q = 33(40) = 1320 veh/hr
Why the other choices are wrong
- Choice A
- The reported 1914 veh/hr runs roughly 45 percent above the true product of the stated density and speed, and no single unit slip or formula substitution reproduces that exact figure from k = 33 veh/mi and v = 40 mph; multiply density by speed directly, with no inflation, to reach the correct 1320 veh/hr.
- Choice C
- The listed 1558 veh/hr sits roughly 18 percent over the true product of density and speed, and no single substitution or transcription error reproduces that exact figure from k = 33 veh/mi and v = 40 mph; apply q = k * v directly, with no inflation, to obtain the correct 1320 veh/hr.
- Choice D
- A reported value of 1030 veh/hr runs roughly 22 percent under the true product of the stated density and speed, and it cannot be traced to one clean arithmetic or unit-conversion mistake starting from k = 33 veh/mi and v = 40 mph; multiply density by speed with no reduction to reach the correct 1320 veh/hr.