The U.S. Department of Housing and Urban Development announced its Rental Assistance Demonstration doubled its capital investment from last year.

RAD exceeded $4 billion in capital investment, which HUD will use to make repairs to the thousands of public housing units that are vacant due to indecent, unsafe or unsanitary conditions.

RAD uses about $19 in capital for every $1 in public housing funds, expanding the ability of local public housing authorities to improve their public housing properties. HUD explained that without RAD, the local housing authorities would take about 46 years to accomplish the same level of repairs.

“Through our innovative RAD program, housing authorities can begin to address the backlog of capital repairs needed in their public housing stock,” HUD Secretary Ben Carson said. “Reaching this $4 billion milestone means expanding opportunity for more families and ensuring they have access to quality, healthy, affordable housing.”

RAD allows public housing authorities to access private investment through public-private partnerships to improve the housing units. The backlog for deferred maintenance was measured at $26 billion in 2010. Since then, about 10,000 units of public housing are lost each year due to disrepair.

Under the RAD program, public housing authorities convert some or all their properties to a project-based section 8 housing platform. This allows them to utilize capital through public-private partnerships.