It's infinitely better than HDA2 at tracking and maintaining lanes.

HDA2 cuts out if there is a break in lines more than 50ft or so.

Openpilot can track the slightest of roads, even able to follow off-road the tracks in grass from a leading car.

It does basically everything HDA2 does and then some, and does it much better.

It has a driver-monitoring camera that you control, that monitors for inattentiveness which is much more effective than simple wheel-torque based sensors.