First off it sounds like a good idea but the logistics, bottlenecks and rising cost can have a huge effect. They must think it through carefully. Trucks are not always the cause. Many pedestrians are also killed.
VIDEO: Heavy truck restrictions
Taxis are also a major cause of crashes because of unroadworthy vehicles and not complying to basic rules of the road.
I don't think it is a good idea to restrict trucks. If Sanral and metro police enforce the basic rules of the road it will be a huge improvement.