The image is the result of fine contamination (an iconic figure of speech: two identities by similarity).  The run with  Roman chariots (quadrigas) does not allow the six-in hand, even if its maximum was usefully a four-in-hand).

The run with the sleigh allows the winter setting, a season where Pirelli tyres are more reliable, as the writing within the image asserts again (PIRELLI PURA RAZZA WINTER / Pirelli, the class winter race) with an identity by spatial contiguity, but dogs would have been harnessed in series, and not in parallel.