The finance ministry in a mid-year fiscal report said 36.8 billion rupees was spent on national roads, including 11.3 billion rupees on expressways, 17.5 billion rupees on highways and 6.9 billion rupees on improvements to roads.
Another 8.9 billion rupees was spent on provincial roads. Under 'Maga Neguma' and 'Gama Neguma' projects a further 1.7 billion rupees and 2.8 billion rupees had been spent on rural roads.
The finance ministry is filling a long existing infrastructure gaps in the island due decades of under-investment in infrastructure, using foreign debt in most cases.
The Asian Development Bank, Japan and lately China have been major financiers of roads.
Roads generate billions of rupees of taxes each year but the money is spent on other areas by rulers, forcing the finance ministry to borrow.
According to a mid-year fiscal report cars and petroleum generated 30.6 billion rupees in excise duties alone.
Motor industry officials say in 2011 the state earned 65 billion in taxes on imported vehicles. The department of motor traffic had separately earned 7 billion rupees on registration and other fees.
Sri Lanka's rulers run a current account deficit in the budget and all capital expenditure is financed by debt. The finance ministry has in recent years maintained capital expenditure around 6.5 billion US dollars.
About 6.8 billion rupees was spent on expanding power infrastructure and 12.99 billion rupees spent on water and sanitation.