Earlier quoted context omitted.
It’s strange to see you advocate for 35mph. In many parts of Southern England I saw 20mph become the norm. It makes a lot of sense in terms of road safety as well as noise, and makes little to no difference to journey times.
20/35 is 4/7 the speed, and therefore it makes every trip take 7/4 as long. So you spend an additional 15 minutes on every 20-minute journey. You're rapidly going to waste more human lifetimes sitting in cars than you would ever save from driving slower.
You can also make other choices that reduce your 15min to begin with. (If the small difference there makes important changes in your life)