I checked Dummett "The Visconti Sforza Tarot Cards", but of course, he is describing the Visconti Sforza deck. I'll bring it in as well just for the comparison:The Chariot depicts a female figure dressed in a long gown incised with the ducal crown, laurel and palm motif. She holds across her right shoulder a thin, long scepter. In her right hand is a disc decorated with the Visconti emblem of a dove in profile above a think ribbon. Although the ribbon shown here is worn, other presentations of the Visconti dove suggest that originally the ribbon bore the legend A bon droyt. The chariot, covered with an ornate canopy, is led by two rearing horses, one mounted by a young man in a wide-brimmed hat. The scene of The Chariot card in the Cary-Yale Visconti deck is substantially different from the Pierpont Morgan-Bergamo card by virtue of the man on horseback, the canopied chariot, and the dove, plus the scenes on the two cards face opposite directions.
Berti and Gonard in "Visconti Tarots", also talking abut the Sforza Visconti card say basically the same thing, but add:This is a triumphal chariot and is referred to as such in one sixteenth-century source; it is usually known simply as "the Chariot" (il carro). The staging of triumphal processions, in imitation of those of ancient Rome, was very common in Renaissance Italy, as Jacob Burckhardt has shown. Some, like Cesare Borgia's in 1500, were in celebration of personal triumphs, staged after a successful campaign. Francesco Sforza, by contrast, refused the honor of entering Milan in such a triumphal procession after its surrender in 1450. But triumphs were usually pure spectacles of an allegorical character. Gertrude Moakley's theory is that the whole sequence of tarot trumps represents a burlesque "triumph" of this latter kind, which is why the term trionfi was used for them, to work out out in detail. On most versions of this card, the rider in the triumphal chariot is indeed a conqueror, often a king, wearing armor and standing. Here, it is a seated queen, crowned and holding an orb; her golden robe is patterned with radiant sun, and her chariot is drawn by winged horses. Some definite allusion may have been intended, but I do not know. A copy of this card was in the Tozzi Set (whereaboutss unknown).
It has been pointed out that the female figure driving the chariot is comparable to many allegories of Glory and Fame typical of the period; it can be found, for example, in Bocaccio's Amorosa Visione and Petrarch's Trionfi.