Not so much cars, but the drivers. This ‘safety first’ methodology that the DOT uses only serves to create bad drivers. Driving is inherently dangerous and we cannot design that out with roadway changes. We need to remove licenses and actually mean it. We need repeated testing for everyone, not just the elderly. If the police did anything but ticket speeders to generate revenue driving might actually get better. It only takes one asshole to ruin the flow of an entire interstate for miles. And they receive no punishment for slowing other people down who are going about lawful business.

PS. Induced demand is mostly myth. Building more lanes is how we gain more bandwidth. Even if the speed doesn’t increase the throughput will and that means more people getting where they want to be. That is how you reduce congestion.

https://www.cato.org/blog/debunking-induced-demand-myth

https://urbanist.co/busting-four-biggest-myths-induced-demand/