It is funny to note that one of the original - and never met - goals of the original President Eisenhower Federal Highway system was to replace bad city-planned roads to reduce congestion. The ironic fact the system increases congestion it by creating choke points to get on and off it is lost by many.
The real root of the problem is that people are either unwilling or unable to live within a short distance to their workplace. Many large cities were not designed to handle the volume of commuters that we have had for at least 20 years. People live in the suburbs (for a variety of reasons; some due to economics, others due to a desire to live in areas with lower population density), and commute to the city centers to work.
The highway system in the United States is rather unusual. Most countries would design a system to maximize the utility. Lots of high density living near high density employment plus walking, cycling and mass transit. Then minimizing problems like traffic jams by using turnabouts and parallel paths. Instead, the United States highway system was built for the military instead. It was created by the Federal-Aid Highway Act of 1956, popularly known as the National Interstate and Defense Highways Act (Public Law 84-627).
Originally this system got raw material from one side of the country to another to manufacture planes, guns, ammo and ships. It was also envisioned as a great lever on the economy. But the immediate social cost of this high-speed bypass was destroying little towns that grew up on existing roads like Highway 66, a road that already crossed the entire country.
But the system was funded at a time when Nuclear War was the next big thing just around the corner. One intention or clear effect is spreading living out into the new suburbs and exurbs to reduce the impact of a nuclear strike on the core of a city. In fact the roads around every major city aren't designed to avoid traffic jams but instead to ensure:
the importance of the Interstate System to evacuation of cities in time of national emergency.
-- the Clay Commission.
This was the time when everyone was told on the brand new TVs that success means 'a steady job, a home out of town, a car, two kids and husband+wife.' That is when they weren't practicing duck and cover.
Where these yahoos intended to put these people fleeting the burning inner cities during war? The imaginary copious amounts of farmland that planners though should be able to support them. Yes, this was during a time when farming was already well on it's way to consolidating into agribusiness.
No, people didn't decide that suddenly the suburbs were the peak of civilization (even if we parody that in the movies.) The citizens of the United States bought a big pile of propaganda. The sad fact is that the people who wrote that propaganda actually believed it was to help them.
The problem can only be solved by reducing the need for people to commute. There are a lot of ways to do this:
Tell that to three generations of management that believe in face-to-face time. Google and other Stack-ranking "Internet Native" companies design their HR system to terminate remote workers or flex workers as fast as they can hire them. Sixty years of white flight, black flight, Mexican-ization, gentrification, urban blights, drug wars, gang wars, the real estate collapse and protectionist nimby laws the problems haven't been solved by staying at home. In places like Irving, California, that are built on the Internet, things got much worse. The demographics keep changing but the work culture and laws didn't.
And the roads? The roads pretty much stayed the same. Literally. As in until you couldn't really drive on them anymore.
Infrastructure's expensive. Someone's gotta pay to make it then someone's gotta pay to keep it up.