Wheels were certainly in use well before 3500BC. http://mentalfloss.com/article/62357/who-actually-invented-wheel http://mentalfloss.com/article/62357/who-actu

Wheels were certainly in use well before 3500BC. http://mentalfloss.com/article/62357/who-actually-invented-wheel http://mentalfloss.com/article/62357/who-actually-invented-w... (A casual Google check will reveal other examples as well) Also parent article mentions metal tools being needed to bore holes for the shaft. Other methods could do this also... people worked intricately with wood long before metal was used (although metal would certainly speed up mass production.) As far as roads, you don't really need roads for a wheel to be useful. You just need a flat semi hard surface. People crossed the US in horse drawn wagons without roads. Not sure where the "roads" argument comes from other than, sure, better roads means more wheeled vehicles.