Answer:
Civil Engineering.
Step-by-step explanation:
Civil Engineering is a field of engineering study that deals with professional practising in designing and developing infrastructures such as transport system and networks, buildings, etc.
Civil engineering is regarded as the second--oldest form of engineering studies in the field of engineering.
A person who studies civil engineering is able to design and develop major projects in transportations system such as road construction, bridges, airports, tunnels, etc.
So, Danny, who is interested in studying transporation networks and system should opt for studying civil engineering.