The episode starts out with Orange Balloon floating over a large map of streets, launching into a discussion about how cities are made up of hundreds of streets. Two hundred years ago, those very streets may have been forests or fields, but motorists got tired of breathing in dust and asks for roads that would take them places faster and more smoothly, an idea that stretches all the way back to Roman times. Back then, people had to use shovels and coal, but now there are machines that can take care of much of the work of building roads. Highway engineers are always looking for ways to make roads better and save money as well, as good roads are expensive to build and expensive to maintain: snow and rain can leave rust and potholes. Even the paint on the highways and roads must be tested to see how clean it will dry and if it'll come off the road too easily. With cities growing, more and more highways have to be built and constantly examined as well - there's a special truck that contain