Sorry I could not disagree with you more. I have lived in both Karachi and Lahore and have traveled frequently in Punjab - areas surrounding Lahore, Gujranwala, Faisalabad and Gujrat and can say it with full confidence that the way people drive in these cities in Punjab is far worse than in Karachi. It's not just my experience by the way but the same thing is said by my colleagues in Lahore who lived in Karachi for a while.
Maybe you have just traveled on main roads/highways in these cities but you have to see how they drive in tiny, non carpeted roads and streets. Gujranwala especially is far worst, however Faisalabad and Lahore are not far behind. You just need to visit the old areas in Lahore to see the mess. There is no traffic sense at all and worse of all in case of accident (which is very frequent there), even when at fault, they the tendency to never accept their mistake but instead they will blame you even when you are driving as per the rules.
The issue you see on Rashid Minhas road by the way is due to the habit of short cuts and the general issue in Pakistani public for not having any patience or regards for others. But the driving ability and sense I've seen is much better in Karachi than other areas in Punjab (can't comment on rest of the country as I haven't been there extensively).