The government will double investment in the next five years to speed up development of infrastructure in the country. Inaugurating a conference on Public Private Parternership, PPP on National Highways in New Delhi today, Prime Minister Dr. Manmohan Singh said the investment in this sector will rise to about one trillion dollars.He said this is necessary to achieve the target of 9 per cent growth during the 12th five year plan. Dr. Singh said the private sector has a potential to play an important role in the development of rural infrastructure and will save cost overruns. He said that infusion of private capital will also ease the pressure on limited resources and improve the efficiency of service delivery.Prime Minister Dr Manmohan Singh called for awarding contracts to private players in a fair and transparent manner to eliminate any possibility of favourtism or crony capitalism. He asserted that public interest must be foremost while awarding Public Private Partnership contracts in the infrastructure sector.Dr. Singh also said the State Governments have to play a crucial role in developing road infrastructure and the objective of infrastructure development to push the growth can not be acheived without their participation.The Prime Minister said an Infrastructure Debt Fund is being set up to enhance the work on the long term projects. He added, a high level committee is already examining measures for financing such ambitious projects.AIR correspondent reports the government has set a target of upgrading 20 Kilometers National Highways per day. Under the National Highways Development Programme, about 25 thousand Kilometers of roads are proposed to be built through PPP mode during the next three years.