The alternative routes are available if they are deemed viable alternatives. Quite what metrics are used to be deemed viable are unknown.
For anyone with this update, who is uncertain about whether this feature is available for them, I'd suggest navigating to a further away destination that can be accessed via different main roads in a similar amount of time/distance.
For anyone with this update, who is uncertain about whether this feature is available for them, I'd suggest navigating to a further away destination that can be accessed via different main roads in a similar amount of time/distance.