QUESTION:
When encountering terrain, what criteria are used to decide whether the
rover goes over an obstacle versus going around it?

ANSWER from David Dubov:
The hazard detection system on board the rover identifies an obstacle as
traversible. Three settings are stored on board at this time and can be
selected by command. For obstacle heigth, these values are: 6cm, 8cm and
13cm (= a wheel diameter). Based on the selected parameter, an obstacle
measured at or above the setting is considered non-traversible. The rover
automatically avoids non-traversible obstacles, turning away and attempting
to find a path to the objective of the traverse which is free of such
obstacles.

Additional measurements are taken from sensors such as the bogie
potentiometers, accelerometers, etc and are factored into the determination
of hazard conditions. All are evaluated in determining if a path is safe for
traverse.