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GATE 2020 CE (CE2) – Question 41

Traffic Engineering and Transportation Planning · Fundamental relationships of traffic flow · 2 marks · Multiple choice

The shown highway flow–density relation is triangular. Which is its corresponding speed–density relation?

Diagram for GATE 2020 CE (CE2) question 41
  1. Figure A
  2. Figure B
  3. Figure C
  4. Figure D

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Show answer and explanation

Correct answer: (C) Figure C

Explanation

Speed is $v=q/D$. On the rising linear branch, q is proportional to D, so speed is constant. On the descending branch $q=w(D_j-D)$, giving $v=w(D_j/D-1)$, a decreasing convex curve. **C** shows this constant portion followed by hyperbolic decrease.