A good explanation is that freeways behave like superheated water in that they are somewhat bistable. Just like water can be above 100C without boiling when the

A good explanation is that freeways behave like superheated water in that they are somewhat bistable. Just like water can be above 100C without boiling when there are no impurities, freeways can transport more traffic throughput than saturation when there are no disturbances. As soon as there are disturbances the freeway can only support a maximum throughput, unfortunately that maximum throughput occurs at low speed so the traffic jam occurs. To get back to the free flowing regime the throughput has to be lower than the maximum for speed to increase. Like with water you can't get back to the superheated regime without stopping the boiling. So yes you can improve throughput and reduce traffic by removing disturbances but it doesn't always work, better to reduce traffic volume in other ways or reduce bottlenecks by widening roads consistently.