Steering wheel or Spare tire?

I saw a thought provoking sign on the back of a truck this evening.

We were headed back to Rachel's house from our house when we encountered a major accident and were forced to make a u-turn. On the route we took to get to the interstate, we were stopped at a traffic light when I saw this sign. It said:

"Is God your steering wheel or is He your spare tire?"

What an incredible way to look at it.

Is God the one steering my life or have I stuck Him in the trunk to pull out in case of an emergency?