[PeterSmit]

I'm not sure if you're from the Netherlands, but I can assure you it's more nuanced that this. Mixing only works when cars are not dominant, so you need low car volumes and low speed in these areas. Residential areas in cities are an example of this: no through traffic, max 30kmh limit.

Most of (new) Dutch road design is designed to give pedestrians and cyclists multiple safe options, while cars have to take the long way round. You can in theory still get basically anywhere with a car if you need, but often (especially in cities) it easier to walk/cycle/take the train/tram/metro. The result is that things can be closer to each other (no parking moat everywhere) so in the end the trip is shorter and safer for everyone, including people choosing to take the car.

[consp]

As an example: More and more "cars are guests" roads are being added. These are usually cycling dominant routes and while completely removing cars might be preferable it's not always possible. Due to the roads being designed as widened cycling paths (and look like it) which barely fit a car you can have cars there but you'd think twice driving there, which makes the drivers more cautious and lowers the car traffic volume a lot. Note: the throughput of a cycling path far exceeds that of a normal road per surface area used (about ab order of magnitude vs cars).