Peak bandwidth of roads happens at surprisingly low speeds, you wanna maximise bandwidth set the speed limit to about 20km/h [1]. Anything higher and road capacity starts reducing.
So reducing the speed limit down to 60/h actually increases the capacity of the road, and reduces the likelihood of rolling traffic jams occurring or persisting.
So reducing the speed limit down to 60/h actually increases the capacity of the road, and reduces the likelihood of rolling traffic jams occurring or persisting.
[1] https://www.researchgate.net/figure/Road-capacity-change-wit...