I eventually came to the mindset....upon delivery, the California folks....within five years....would have 20-pages of mandates and safety-code.....making it a problem to license or tag the buggy.
I also think that they would mandate...some bigger horses would be noted as 1.5-HP....while ponies would be classified .5 or .7 HP.
Seatbelts required? Yeah....more than likely.
Protection from flipping over? Probably mandated.
Mandated rest after 10 miles of pulling a buggy? Probably.
If you got rid of cars, and buggies.....just having bikes....would they stop the mandating? I doubt it.....there's likely to be 1,000 pages of bike mandates eventually.