The goal was to make a car that could go the slowest.
It had to roll completely down the ramp and not stop until it passed
the end.
Separate axle connectors for each wheel could make a car go slower
than one with single axles.
However with wheels on single axle there can be more friction if the
wheels are squeezed close to the car -
so much so that the car could stop on the ramp.
It took some time and lots of tweaking to get a very slow car.