Within the US, leftists often cite the interstate system as a government program everyone likes. Which is reasonable enough.
But US highways share the downsides of socialism, not just the upsides. Consider a Soviet breadline. The bread is free, so everyone wants lots of it, and demand exceeds supply. The way to reduce demand is making everyone wait so long that the annoyance of waiting deters them. Hence, long lines. (And this is a deadweight loss; when bread is expensive, at least the bread company gets rich, but a long line benefits no one.)
US interstates have the same problem. They’re free and well maintained, so demand is high. When demand exceeds supply, everyone wastes time in traffic jams, the American equivalent of the Soviet breadline.
If roads were privatized, they’d be pretty expensive, since infrastructure is a natural oligopoly. But from a road company’s perspective, traffic jams are terrible; they hurt the “customer experience” and reduce revenue (traffic jam = no one can enter the road = no tolls). The natural solution is raising prices until demand goes down. And then you’d never have to wait in traffic again.