The AP-41 motorway linking Madrid and Toledo has gone bankrupt as Spanish motorists steer clear of toll-roads to save money.
There are 21 companies running privately-owned roads in the country.
Nine motorway concessions are in serious financial trouble.
Government figures show daily usage of toll roads has plunged by 28 percent. In the first quarter of this year, the average number of cars using them was on a level last seen 14 years ago.
Central government has already propped up struggling concessions with more than half a billion euros.