These two goals are incompatible. If the idea is that self driving cars don't need to park, they can just drive around in circles until needed(which is an absolutely insane idea for a whole number of reasons, but let's stick with it for a second), then that will only increase not decrease traffic.
>>I could see them make the way to Europe too
I've love to see a Waymo navigate some narrow British roads where there is no road signage and there is no defined priority.
Like, this is a real situation encountered on a road here by myself just few months ago, skip to 1:30 to see the interesting bit - I'd love to hear proponents of self driving cars explain to me exactly what the car would do in this case. Hand over to a remote operator? There is no signal there, sorry.
You can park them further away from their destination, this increases traffic massively driving to the parking.
As well, if the ride is comfortable then people will be willing to plan longer commutes. An induced demand which increases the number of miles driven and hence traffic. Watching TV in the car is a major appeal of self driving.
I'm also convinced that the peak share of vehicles in use is less than 60% at any time of the day and year, but happy to be proven wrong.
> At the start of the 20th century, bikes far outnumbered cars in Dutch cities and the bicycle was considered a respectable mode of transport for men and women. But when the Dutch economy began to boom in the post-war era, more and more people were able to afford cars
Amsterdam also has 50% higher population density than Los Angeles, despite housing much fewer people.