31.4. Illustration of mean speeds

Try these first

1. 1.

   What is time mean speed?

   Hint

   Think about how average speeds are calculated over time.

2. 2.

   How do we calculate headway?

   Hint

   Consider what spacing and speed mean together.

3. 3.

   What is the formula for time mean speed?

   • v = sum(v_i)/n
   • v = sum(v_i * q_i)/Sum(q_i)
   • v = 1/(n * spacing)

   Hint

   Focus on how average calculations are performed.

4. 4.

   True or False: Space mean speed is always greater than time mean speed.

   • True
   • False

   Hint

   Review the definitions carefully.

5. 5.

   A stretch of road has a time mean speed of 30 m/s with 100 vehicles traveling. If the headway is recorded as 2s, what is the space mean speed?

   Hint

   Apply definitions and remember how each speed type is derived.

6. 6.

   In a test scenario, two sets of vehicles with average speeds of 10 m/s and 50 m/s, find the relationship between flow and density given the speed of incoming versus outgoing vehicles.

   Hint

   You may want to break down speeds by their mean methods and establish flow parameters.