Car jacking/snatching is very common everywhere, even in US, In Washington DC, I knew someone whose car was surrounded from all four sides by other cars in broad daylight and had the car snatched from him on gunpoint, sometimes teenagers do it for thrills. But in anycase Karachi is not unique, but since it has higher car ownership ratio and so the higher car snatching incidents. Its sad. There are ways, and the most effective way is public, police partership and convincing the local government official to have more police cars patroling the cities, (not those dingy old Pickups) as those are not proper chase vehicles. Public in Lahore and ISB have better sense of safety due to police possessing modern equipment, proper color coded chase cars, radio equipment with quick response capability. I have travelled on ISB-Lahore Motorway, Pakistan seems like any other western or any developed country, atleast on the motorway with Police and modern CNG/Petrol stations with convenience stores.
Anyway, Karachi needs to be modernized on international scale, as yet, it does can not even compete with smaller Pakistani cities like Lahore and Islamabad, in terms of basic public safety institutions such as Police and firebrigade, hospitals, schools, etc.