As I've said before, competitive cycling should only take place on enclosed, purpose built tracks. The inconvenience (and in the case of the T de F, the economic damage) caused by events being held on public roads is enormous. It would also lessen the chances of something like this happening.
Why people would choose to stand by the side of a road to see a few dozen cyclists hurl past is somewhat of a mystery. It's not what you'd call a long lasting spectacle. Half a minute or thereabouts and I guess that's that. If it was held on a track spectators could watch the cyclists go round and round for hours on end. Far better value. If the organisers want hills (and it always intrigues me why they organise their events in the most unsuitable places to ride a push bike) I'm sure they could design a track with a few slopes included.