Question

Assume you are an observer standing at a point along a three-lane roadway. All vehicles in lane 1 are traveling at 30 mi/h, all vehicles in lane 2 are traveling at 45 mi/h, and all vehicles in lane 3 are traveling at 60 mi/h. There is also a constant spacing of 0.5 mile between vehicles.
If you collect spot speed data for all vehicles as they cross your observation point, for 30 minutes,
what will be the time- mean speed and space-mean speed for this traffic stream?

Answer 1

Answer:

Explanation:

Given data;

• In line 1, v1 = 30mi/hr

• in line 2, v2 = 45mi/hr

• in line 3, v3 = 60mi/hr

• therefore time mean speed = v1 + v2 + v3 /n

• = VT = 45mi/hr

• space mean speed ; Vs

• harmonic mean = 1/V = 1/v1 + 1/v2 + 1/v3

• V = 13.85mi/hr

• Hence Vs = V x n = 3 x 13.85 = 41.55mi/hr