NEW DELHI : The National Highways Authority of India has invited bids for 9 national highways under its ‘toll-operate-transfer’ model as it seeks to raise Rs 6,200 crore through leasing out operational toll roads. The auction will involve highways running across Andhra Pradesh and four in Gujarat. The total length of these highways is just under 700 km.Interested companies will be able to submit their bids till January 9. Under the TOT model , pension funds and PE firms are allowed to lease government-owned national highways for 30 years for an upfront payment. The lessee, in turn, gets the right to collect the toll, operate, manage and maintain the highway stretch.The government can also increase the concession period in later stages, if the concessionaire wants. NHAI may provide a risk cover to the lessee for any unforeseen circumstances such as a rapid fall in toll collection and any structural or engineering fault on the highway.