Track: this continues track 1 to 3. It has variables and uses the timer.

Here starting from where the car drives itself round it now start
when a traffic light goes from red to orange to green. The speed
and the angle of turn can be altered initially before the start
then during the race. On crossing the finishing line the time is given
to complete the circuit.

Challenge the students to see who can achieve the fastest time!   

By this time itís hoped that the students have begun to grasp Scratch
so I start with asking about what is need and how is it going to do it.
See crib 1.