He does that sort of thing a lot, really. Just about every representation of him has had some variety of personalized vehicle attached to it. We've had various types of Joker-vehicles in the comics, of course - and I'm pretty sure in B:TAS - then there was the Jokermobile in the '60's show, and variations in the various cheapo cartoons from Filmation and so forth. In movies, there were those purple cars with the green hoods that his men drove in the original 'Batman' (and, of course, the parade float with the balloons and his personalized helicopter), and in 'Dark Knight', there was the modified circus truck his men drove when going after the police convoy. I haven't seen 'The Batman', so I don't know whether he had any in that show, but I know he drives the classic version in the 'Brave and the Bold' show. Heck, the guy could hold an exhibition at a car show...