1. the physics of intersections
But Officer!…
the physics of intersections
A Rich Context Problem

2. Have you ever...
Approached an intersection when the light changed from green to yellow and:
knew you couldn’t stop
knew there was no-way that you could make it through
Are there real “dilemma” zones in all or some intersections?

3. Negotiating an Intersection...
There are two scenarios we must consider:
stopping safely
making it through safely

4. Safe Stopping... Parameters that will affect this:
maximum rate of deceleration (ad)
reaction time (tR)
Variables to consider:
initial speed of car (vi)
distance from the intersection
Put this into EXCEL

5. Safe “Going-For-It”... Parameters that will affect this:
maximum rate of acceleration (a)
reaction time (tR)
duration of yellow light (tY)
length of car (L)
width of intersection (W)
Variables to consider:
initial speed of car (vi)
distance from the intersection
Put this into EXCEL

6. Do Dilemma Zones Exist?
What condition would tell us whether or not dilemma zones really do happen?
I don’t know what to do! I’m too close to stop and too far away to get through - YIKES!

7. Group Assignment (Due Sept 24)
Discuss this within your group and identify an intersection somewhere around the King’s Campus
Measure all the relevant parameters for this intersection and assess whether or not it contains dilemma zones.
Submit your group report (maximum of 2 pages typed plus accompanying graphs). In this you should give 3 possible traffic scenarios and look at under what conditions this intersection could become un-safe.