They've already spent $324 million on the Main line and are in the process of raising the rest.
When METRO was formed, Houstonians voted to increase the local sales tax by one cent to fund the organization.
METRO Chairman David Wolff told members of the Greater Houston Partnership it's time for that to be fully restored.
"Along the line, one quarter of this sales tax was diverted from METRO, taken from METRO, diverted to the city and the county and the multi-cities for building of roads. I do not feel this was proper. This money was voted by people of this area for transit. And I think that one of the things that we have to work on with the mayor and the county commissioner's court is restoring to METRO this full one-cent sales tax."
Wolff says that quarter of a cent represents about $100 million a year in revenue that could go to METRO.
"No other transit agency in the country has had to divert a portion of its sales tax revenue for road building, and we shouldn't."
But that $100 million a year helps to maintain roads in Houston and Harris County. The agreement allowing them to divert that money expires in five years.
But the political climate is uncertain for METRO. Annise Parker has said she'll clean house at METRO and overhaul the organization. Gene Locke serves as legal counsel to METRO and has political supporters there.
What happens next could be up to Houston's new mayor.
Laurie Johnson. KUHF-Houston Public Radio News.