31.8. Summary

Try these first

1. 1.

   What is time mean speed?

   Hint

   Think about how you measure speed over time.

2. 2.

   What does space mean speed focus on?

   Hint

   Consider the duration vehicles spend traveling.

3. 3.

   What is true about time mean speed?

   • Always less than space mean speed
   • Always equal to space mean speed
   • Always greater than or equal to space mean speed

   Hint

   Consider how both speeds are defined.

4. 4.

   Fundamental diagrams relate which three elements?

   • Speed
   • density
   • flow
   • Age
   • speed
   • density
   • Speed
   • flow
   • time

   Hint

   Focus on important traffic flow measurements.

5. 5.

   You observe a traffic stream for one hour with 180 cars passing. Two are moving at 10 m/s, five at 20 m/s, and the rest (173) at 15 m/s. Calculate the time and space mean speeds.

   Hint

   Use the definitions of mean speeds correctly and set the equations up carefully.

6. 6.

   If a road can hold a maximum of 40 vehicles but sits at 30 causing slow movement, how does this reflect in a flow-density diagram?

   Hint

   Refer back to how flow changes with density on that diagram.