The Redbird is a camouflaged sport coupé with all the armaments of the Batmobile. In addition to that, there are polarizing windows and exterior sliding bulletproof conversion panels, enabling it to be driven by an uncostumed Tim Drake as a "normal" car.
When Drake was sent away to boarding school, following the quake known as the Gotham Cataclysm, he was forced to give up the Redbird by 'selling' it to a disguised Alfred. While at boarding school he developed an advanced skateboard he called the "Redboard". More recently he utilizes a modified 491cc, liquid-cooled "motocross" Batcycle for his transportation needs.
With Tim Drake moving back in Gotham, this time as the adopted son of Bruce Wayne, the Redbird is restored to him, but it is badly damaged during an ambush. Robin takes in consideration the idea to scrap it and have built something scarier to drive.
His resolution doesn't seem to come to a pass, as the Batcave still holds one or more Redbirds in storage along with other Batmobiles, and only a few days later Tim Drake is shown driving a new or a refurbished Redbird, identical to the previous one.