

This is an interesting chart from Bloomberg Green comparing some of today's innovations against innovations of the past. At the top of today's innovations are EV batteries, which from 2010-2020, saw annual deployment growth similar to that of US WWII aircrafts. However, when it comes to reducing costs, both EV batteries and solar PV modules come out on top with annual declines approaching almost 20%.
Of course, these probably aren't perfect comparisons. If you look at EV batteries and solar PV modules from 2020 to 2023, their growth rates jump to 72% and 39%, respectively. So who knows if these are the right time slices to be using in order to accurately capture the "key expansion periods." Regardless, it does provide some historical context and it does say something. These are important innovations.
The Dutch now believe that the number is 230cm. This is an increase from a previous recommendation of 200cm. The thinking behind this number is roughly as follows. Apparently there are Dutch laws stipulating that bikes can't be wider than 75cm. So this is the starting point.
But since it's impossible to always ride in a perfectly straight line, there seems to be a generally accepted rule that, at an absolute minimum, cyclists need about 100cm of width to themselves.
If you now double this so that two people can ride side-by-side, you're at 200cm. This is an important design criteria because the Dutch also seem to believe that (1) cycling is a social activity and (2) a child should be able to ride beside their parent. (Love this!)
Finally, add in a bit of buffer so there's room to pass slower cyclists and/or nobody feels like they're going to crash into oncoming cyclists, and you get to 230cm as the ideal width of a single bike lane.

