Poll

Do we think "whip" means car because whips were used to steer horse-cabs back in the day? This crossed my mind when I was reading Edith Warton's 1905 novel The House of Mirth ("'You don't know how a fellow has to hustle to keep this thing going.' He waved his whip in the direction of the Bellomont acres, which lay outspread before them in opulent undulations...", p. 86), which made me think of the Cam'ron song "Horse & Carriage."

[Verse 1]
You might see Cam in designer underwear
New reclining leather chair, reminders everywhere
How we pull up in whips, the minors stop and stare

...

[Verse 2]
Right now too tipsy to drive
But I got my horse and carriage right outside

Several "whip" entries on Urban Dictionary support this connection, including the top rated one (591 up, 63 down), which goes into even more specifics that I'm not sure I believe.

...various hip hop artists noticed that the Mercedes-Benz logo resembled a steering wheel. They then proceeded to use the old term "whip" to describe any Mercedes-Benz vehicle. The term has now been generalized to classify any expensive automobile.

You don't know how a fellow has to hustle to keep this thing going. What do we think?