GATE 2021 CE (CE1) – Question 63

Traffic Engineering and Transportation Planning · Traffic studies: flow, speed, peak hour factor, accident study · 2 marks · Numerical answer

Observed spot speeds are 40,55,60,65,80 km/h. Find space-mean speed in km/h to two decimals.

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Correct answer: 55.5 to 58.5

Explanation

Space-mean speed is the harmonic mean of spot speeds for this sample: $u_s=5/(1/40+1/55+1/60+1/65+1/80)$. Evaluation gives 56.9910 km/h, or **56.99 km/h**. The arithmetic mean of 60 km/h is the time-mean speed.