Cars on a Monday. Lorries and HGVs switch on Wednesday. All remaining traffic on the Friday.
Done!
(Note that it was a follow up to patently satirical parent comment, but it does remind me that Sweden made the change on 3rd Sep 1967)
Edit: why disagree? We should be focusing on education and testing for the best improvement as it will be beneficial to multiple problems.
Kind of https://www.worldatlas.com/r/w1300-q80/upload/58/85/6f/shutt... vs https://mobycon.com/wp-content/uploads/2019/09/IMG_20190725_... - that's not quite a fair comparison but that kind of thing.
Also pedestrian deaths on the highway: the number is so minuscule it doesn't even register.
And they aren't as dangerous as many would think. Cars have done lots to improve such collisions (airbags, crumple zones). A head-on collision between cars is still two relatively lightweight objects. Hit a concrete wall, overpass support, cliff or tree and you are going up against an object that makes a care look like tinfoil. The head-on seems bad, but it is more survivable than having your car bisected around a tree trunk. Or get pulled under a big truck.
This is only really true for a very small number of places in the US, even smaller when you consider the lack of enforcement.