If infrastructure is to be automated, there obviously needs to be automated transportation. Taking raw materials to processing plants, processed materials (such as machine parts) to manufacturing plants, and products to their destinations - all this haulage is laborious and unstimulating work. It is desirable to free people from such tasks using technology.
For an automated post-scarcity infrastructure to be a reality, there must be not only vehicles capable of moving around autonomously, but also automated logistical systems that are capable of directing these vehicles. Autonomous logistics is now a fully mature technology; there are computers that can autonomously manage warehouses, order products that are running low, and ship packages around the world. Connect these smart logistical systems to driverless vehicles and you have an automated transport infrastructure, capable of joining together a post-scarcity world economy.
Bear in mind that decentralizing the means of producing food, water, energy and machinery will massively reduce the amount of haulage to be done. When you can fabricate everything you need and most of the things you want in your backyard, there is no need for anything to be delivered to you except for raw materials like scrap metal. It has been said that with digital fabrication, products travel most of their journey at light-speed in the form of information.
As well as cargo, our own means of travel can be greatly improved using existing technology.
Luckily, better methods of transport exist. A few of the more exotic ones are explored below, but a more familiar example is the train. Trains are one of the most efficient forms of transport in terms of energy per unit weight moved. They are also the easiest to automate, with some already being so, such as the Docklands Light Railway in London.