(a) Four ways in which physical factors may hinder the development of road transportation are:
(i) Rugged highlands create pattern for the development of roads
(ii) Climatic factors like rainfall can wash away existing roads or make it more difficult to construct new ones
(iii) Rivers, especially large ones do contribute greatly to the development of roads as huge amount is spent in the construction and erection of bridges
(iv) Swampy area is also a problem as it also takes large amount of money to construct bridges and flyovers across them.
(b) Four factors responsible for the poor network of railways in tropical African countries include:
(i) Capital costs for maintenance and operation of rail transport are usually high
(ii) Lack of spare parts and technical know-how tend to reduce the rail transportation
(iii) Rail lines are constructed only around mineral or agricultural producing areas hence the absence of these products results in low development of rail
(iv) it is relatively too slow and people do not want to travel with it.