VG247 reports that a "source familiar with the matter" has shed some light on the rumored return of Carmageddon. According to the source, an unnamed company has purchased the Carmageddon rights from Square Enix, with an official reveal planned before E3, though it will not be shown at the convention. According to the recently discovered Carmageddon website countdown timer, the reveal is seemingly set for June 1. The game's developer hasn't been revealed, though Stainless Games seems a reasonable possibility given it developed the first two titles in the series.
The source adds that said website is not actually owned by Square Enix, seemingly despite Whois information to the contrary. Assuming the Carmageddon rights were only recently transfered from Square Enix, it's possible that the domain information has not yet been updated.