The Bulgarian government is considering inviting investors to help it develop an electronic system for truck tolls. The project, which is worth up to US$648.26 million, will be developed on a public-private partnership (PPP) basis. "We are looking for heavyweights, partners capable of making a serious investment of 200, 300, maybe 500 million euro, depending on the estimated cost of building such a system," Lilyana Pavlova told reporters at the Southeast Europe Business Forum.