Cities have poor average travel speed because they're poorly designed.
Design new cities from scratch.

Cities can't be saved. Abandon.

Far more likely are those tailgating others, and failing to leave a safe space in traffic and at intersections, failure to stay back of the white line so you will be delayed entering an intersection and avoid getting T-boned by a red light runner.

The average transit speed across major cities is around 15 MPH. Only a person incredibly weak in character thinks racing from light to light at high speed could possibly be a good idea.

Sooner or later they will hit someone from behind, probably hurt or kill someone, get sued and lose everything - and probably convince themselves it was someone else's fault.

Muscle cars belong on the raceway where the big boys are. Not on the road terrorizing moms and kids in SUVs like some kind of coward.

Postscript: When being tailgated, I pull over to let them pass. When being followed by those too dumb to hold to the speed limit, I also pull over to let them pass.

Far be it from me to keep them from their speeding tickets and increased insurance rates. And I have no problem leaving early enough for my appointments to not be late anyway. Even if I were late, I would not speed. Why? Because it doesn't work.