No idea, but I was waiting in the usual traffic queue on Rama 4 the other day to turn right onto the Sukhumvit road.
On the pavement, there were barriers with a sign saying no riding on the pavement and if caught 2000 b fine.
Along rides a bike taxi that moves the barrier and carries on along the pavement.
Of course, everyone sees this, and it's then a flood of bikes along the pavement. The time I was sitting in the queue, 200 bikes must have gone along the pavement. Imagine 2000b for each.
No good putting up a barrier with no police sitting in wait to catch people.