The public OSRM hosts answer 429 above about one request a second. The trip
overview and the road trip waited that out and asked again; the day route
took the first refusal as final and drew straight lines between the stops
until the next edit, which is what a day with a change of mode or a quick
switch between days ran into. Both the day route and the overview now go
through one retry helper: a rate limit is waited out, as long as the host
asks when it says, and a refusal the host meant still ends at once.
Maurice