The land and transport ministry has outlined plans to expand the use of revenues from gas and other automobile-related taxes, currently used for road construction, for projects ranging from more ecologically friendly roads to electronic toll collection systems, ministry sources said Friday.

A draft by the Land, Infrastructure and Transport Ministry features plans to plant more trees along urban roads, expand subway links and subsidize the installation of pollutant-removal devices on big diesel vehicles, the sources said.

One principal objective of the proposals, they said, is to combat the "heat island" phenomenon in urban centers where the heat in the air is trapped by auto emissions.