Adam Driscoll is pedaling his bicycle across the United States, and gravity is not his friend.
Not even when he's rolling down hills.
And he's already rolled down some pretty steep ones — the sort of slope where they post big eye-scalding yellow warning signs at the top, urging truck drivers to test their brakes before plummeting down the grade.
The sort of slope that spreads smiles across most cross-country bicyclists' faces because they know, as they crest the summit, that for the coming downhill miles gravity will whisk them along at a brisk pace even as they rest their weary legs and wheezy lungs.
Driscoll is not like most bicyclists.