dxb, you know the neatest things! Yes, it reduces wind resistance, primarily from not having the rider's feet and legs "protruding" into (and thus interrupting) the air flow. Man, I hope that sounded good--I just made it up!

Look what I found:
TOD(D), OUT ON HIS
Construct:
Definition: Incomparable, supreme, splendid.
Use: He was out on his tod(d) as a player.
He was excellent as a player.

Derivation: 'Todd' - one's own, alone. Perhaps rhyming slang - on one's Tod Sloan. (Concise Oxford Dictionary). Alone - to work alone. (Partridge). From:
http://corkslang.com/term/toddoutonhis/