The other day I read a super interesting article about the constant travel time budget (German). Basically we invest 60 to 90 min of time to travel each day. This has stayed constant for decades and is rather universal in the world. The article is quite lengthy and detailed, I want to recommend to read it and just give my own conclusion here.
The speed that we can travel with has increased over time. We have cars, we build more long-distance roads. There are high-speed trains, and planes. If we kept the distances the same, the time spend on travel would decrease. But that's not how it appears to work, we rather reinvest the saved time to travel more distances. Basically that means we will structure our environment such that the travel time we invest stays in this range. As people will travel more, there is less need for a local grocery store in the neighborhood, one can just take the car and go to the big one at the edge of the city. Businesses have to compete within a larger radius, and therefore there will be concentration. In small villages everything will die out as people take their car to the next larger district.
But with a bike the distances do not get longer over time. And they will always stay inferior to the ones that one can pass with a car. If the majority of people are willing to invest their travel budget into car travel, cities will be locked into a structure that is not bike friendly. One would have to explicitly foster smaller structures such that biking would become appealing again.
Amsterdam and København have made the transition to a bike city, but it took a lot of willpower. If we are just going to “make traffic flow”, then the structures that emerge will much prefer the car because it is the fastest to travel distances. We will need to make car travel so unappealing that long distances become inefficient and that local businesses have a chance to survive. And that idea will likely not get much support in politics, so we are going to be stuck with car cities for quite a while to come.