you reach the sub-tropical zone of your final destination (Coroico), the
road degenerates into an inch-thick cake of orange dust.
At this point the venture goes off-piste as you slide and skid and
try to overtake trucks which churn up their own volume in dust. This means
you are cycling in an opaque orange bubble much of the time.
Miraculously none of us went over the edge and the worst injuries were
a few skinned elbows. One advantage was the film of dust on all exposed
skin which removed the need for sunblock or insect repellent.