The Halo vehicle is a rather futuristic concept that runs on just two wheels, and is still, more of a car than a bike. Designer Nicholas Womeldorff has kept his focus on efficiency, minimizing both drag and friction for the vehicle.
There’s a large magnetic loop passing through the front wheel, and it generates a strong magnetic field to power the vehicle and the wheel. It is this magnetic force that puts the wheel into forward and reverse motion. The very same magnetic force also provides the rotation in axis for steering the front wheel drive vehicle. Since it is a magnetic field directly powering the wheel, the number of moving parts involved, and thus friction and loss are reduced greatly.
Broad wheels on the concept most likely handle the balancing, though it appears that it would still require additional supporting mechanisms, probably gyros to stay in balance. Also, the renderings don’t make seating very clear, and the area appears to be mostly cramped and uncomfortable.