What would you consider ambitious? Mandate that ICE cars be 30% more fuel efficient in 2025 OR 80% by 2030? And is it better to have ambitious goals vs realis

What would you consider ambitious? Mandate that ICE cars be 30% more fuel efficient in 2025 OR 80% by 2030? And is it better to have ambitious goals vs realistic goals? What might the impact of society be if we put up very ambitious goals but fail them all massively, what will happen to the trust of government institutions? P.S I have a B.Sc in Energy engineering and working on a M.Sc in a field of renewable energy and I'm very skeptical of the goal politicians make, many goals who should be fulfilled when they have long since left office.