GATE 2026 CE (CE1) – Question 60
Traffic is moving on a 6-lane dual carriageway road. Traffic volume per direction during peak hour (08:00 am to 09:00 am) is 6000 veh/h. It is assumed that the traffic is distributed uniformly across the lanes in each direction. Just at 08:00 am, a truck goes out of order on the middle lane of one side, thus disrupting the traffic on that lane in one direction. The lane capacity under normal conditions is 2000 veh/h/ln and under queue formation it is 1600 veh/h/ln. The traffic resumes at 08:30 am on removing the truck from the middle lane. Hourly traffic volume after 09:00 am reduces to 5000 veh/h/dir.
The number of vehicles in the queue at 10:00 am is ______ (*in integer*).
Practise this question in The GATE Grind →
Show answer and explanation
Correct answer: 2200
Explanation
From 08:00 to 08:30 only 2 lanes work, so the discharge is $2 \times 1600 = 3200$ veh/h against 6000 arriving. The queue grows by $2800 \times 0.5 = 1400$ vehicles. From 08:30 to 09:00 all 3 lanes work under queue formation, with a discharge of $3 \times 1600 = 4800$ veh/h against 6000, so the queue grows by $1200 \times 0.5 = 600$ to 2000 vehicles. From 09:00 to 10:00 the demand is 5000 against 4800, which adds $200 \times 1 = 200$. The queue at 10:00 is 2200 vehicles.