FE Civil Practice Question Solution included after investigation
CASE E-106 · FE

The PM Peak That Sent 199 Cars In, Not 306

The project generated 306 total trips in the PM peak hour, but only 65% were entering. The inbound design demand was about 199 veh/h.

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Inspect, commit, prove, fix, and sign off.

Case E-106 engineering failure visual
HOW THIS WORKS

Think like
a real engineer.

Follow the investigation process used in the field — in five guided steps.

1

Inspect

Review the problem, diagram, and evidence.

2

Commit

Choose your hypothesis.

3

Prove

Run calculations and test your idea.

4

Fix

Select and validate a safe correction.

5

Sign Off

See the full debrief and key takeaways.

Case Brief

SAME PRINCIPLES. HIGHER STANDARDS.
PROBLEM STATEMENT

A proposed residential development has 400 dwelling units. The planning rate is 8.5 vehicle trips per dwelling unit per day. Assume 9% of daily trips occur during the PM peak hour and the PM peak directional split is 65% entering and 35% exiting. Determine total PM peak-hour trips and entering PM peak-hour demand.

Transportation Engineering Civil Design Verification Root Cause Analysis Safe Correction
E-106
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DEBRIEF (LOCKED)

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CASE CLOSED · ENGINEERING VERDICT

What actually failed — and what should change.

What failed

All peak-hour trips were assigned to one direction.

What was missed

The 65% entering directional split.

Corrected model

Daily trips × peak-hour fraction × directional fraction.

QUICK ANSWER

400×8.5=3400 trips/day. The PM peak total is 3400×0.09=306 veh/h. Applying 65% entering gives 198.9≈199 inbound veh/h.

ENGINEERING TAKEAWAY

Generate total trips first, apply the peak-hour fraction, then apply the directional split for the movement being designed.

CASE QUESTIONS

Questions this case should settle.

How do you estimate peak directional project traffic?

Multiply daily trip generation by the peak-hour fraction and then by the directional split.

NEXT FE PRACTICE QUESTION

The Lane That Carried 1,800 veh/h, Not 1,227

Transportation Engineering · 5–10 min

Continue Practice →
WHAT YOU’LL LEARN

Real failures. Lasting skills.

Each case is designed to build the judgment, analysis, and confidence you need for engineering exams — and beyond.

  • Apply core engineering concepts to real-world problems
  • Practice structured troubleshooting and analysis
  • Strengthen exam-ready thinking through realistic scenarios
COMMON QUESTIONS
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Basic subject familiarity helps, but every case is designed to teach through the investigation itself.

How long does a case take?

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Are the cases aligned with engineering exams?

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What happens after I complete a case?

The sealed debrief unlocks with the root cause, corrected reasoning, fix, and takeaway.