Equipping your peasant workforce with wheelbarrows instead of making them carry everything is a very good idea. Since they don't have to carry their resources, they can move faster and haul more. In the game, researching this tech has similiar effects, but there's no graphic effect to accompany it, like with most technologies.
Available to: All
Researched at: Town Hall
Cost: 175 Food, 50 Wood
Effect: Peasants move 10% faster, carry 25% more resources. Enables Hand Cart.