how did the trans saharan trade routes lead to increased efficiency, technological advances, human development and interregional trade

Trans Saharan trade was very important for the growth of new trading cities.

Explanation:

"Trans-Saharan trade" was called by this name because it crossed the "Sahara Desert". The West Africans used to exchange their local products like gold, ivory, cloth and salt for goods like horses, books and swords from North America. There was growth of new trading cities.

Inter-regional trade of luxury goods brought more innovations, whether it was in transportation or in commercial technologies. There was development of economy along with use of compass (for directions while travelling in desert) and larger ship designs leading to technological advances. Travelling for long distance meant people should knowledge of environment (monsoon winds). Also, there were cross-cultural interactions which resulted in artistic, literary and cultural interactions.

Thus, all this led to more efficiency, inter regional trade and technological advances because of trans Saharan trade.