Anyone know why this can't be implemented for early production cars without the auto-pilot software? Almost all aftermarket GPS systems and both Apple and Google maps do this so the data obviously exists. It should be simple to add this display to the navigation/map screen - preferable at all times, not just when actively navigating the way Apple does it.
Ideally, the information should not (only) come from a database but should be supplemented by a camera reading the actual road signs. That's how BMW does it and it makes a difference, e.g., in construction areas and on roads with dynamic traffic control (speed limit changes depending on traffic and other conditions). Also, databases tend to be outdated.