After taking the exam, unlike his peers who went straight to work for the native Authorities, Usman decided to join the colonial civil service as a civil engineer.
[2] Between 1950 and 1953, he was in training at the Yaba polytechnic and spent other months as an apprentice under public works engineers.
In 1954, he obtained a scholarship from the Northern regional government to study civil engineering at University of Sussex.
Usman recognized that there is a poor attitude towards road and building maintenance by the government, placing some blame on over protection of civil servants and shoddy work by companies lacking necessary manpower.
[2] His tenure saw the completion of the Lagos-Ibadan expressway, the Benin-Shagamu dual carriageway and the A2 road, linking Warri-Benin-Okene-Abuja-Kaduna.