Do you have a young lad in your home who loves vehicles and transportation of all kinds? I think it is in their DNA.
On the way to school the other day my 4 year old son was asking about traffic lights and why we have them and stop signs and why they are red and not green (his favorite color). It occurred to me that his ever growing collection of toy cars at home are riding around like crazy without any traffic signs at all. A completely dangerous situation!