The GATE Grind

GATE 2020 CE (CE1) – Question 42

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

Traffic flow q and density D are related as shown. Which depicts the shock-wave condition?

Diagram for GATE 2020 CE (CE1) question 42
  1. Flow at point 1, q1 = qmax
  2. Flow changing from point 2 to 6, q2 > q6
  3. Flow changing from point 3 to 7, q3 < q7
  4. Flow at points 4 and 5, q4 = q5

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: MTA

Explanation

Wave speed between states is $(q_2-q_1)/(D_2-D_1)$. Transition 2→6 moves to denser, lower-flow traffic and produces an upstream-moving congestion wave, illustrated by B. But the wording does not uniquely restrict the possible wave states. The official item is **MTA**, which is preserved.