There isn’t much left about this mode in the files, it seems to have been removed prior to the E3 2005 demo. In the American XBOX release, object layouts in 6 tracks remained and here they are, restored.
Presumably, you’d drive inbetween traffic cones for 1 lap, and it would play out similarly to Crashinator. Which is probably why it got cut.
FYI: “Cone Attack” is the mode’s internal name, while Crashinator’s is “Kamikaze”.
Made possible with the CTTR Editor by NeoKesha.