It really hasn't begun in earnest.
Moped, not bicycle - for regulatory purposes, i'm not labeling their riders, just their rides.
But probably a lost cause, the cycling industry won't support it.

Injection molded motorcycles - don't try to sell me the 1st plastic Harley Davidson, regardless of engine size.
You read it here first - Harley Pathfinder - mass produced, injection molded - optional recording/speaker for genuine Harley engine noises.