The Alameda Corridor-East (ACE) Construction Authority was established in 1998 by the San Gabriel Valley Council of Governments (SGVCOG) as a single-purpose construction authority to implement a construction program intended to mitigate the vehicle delays and collisions at rail-roadway crossings resulting from growing freight rail traffic in the San Gabriel Valley. The ACE Trade Corridor rail mainlines through Southern California carry 16 percent of all oceangoing containers in the United States and have been designated by Congress as a Project of National and Regional Significance. With trade volumes through the Ports of Los Angeles and Long Beach projected to grow, train counts through the Valley are expected to increase by 150 percent by 2042, resulting in additional adverse crossing impacts. In 2017, the SGVCOG was restructured and established the SGVCOG Capital Projects and Construction Committee, as a successor to the ACE Construction Authority with full responsibility for implementing the ACE Project.
The ACE Project is a comprehensive program of constructing grade separations, where the road goes over or under the railroad, at 19 crossings (resulting in the elimination of 23 at-grade crossings) and safety and mobility upgrades at 53 crossings. Construction has been completed on fourteen rail-roadway grade separations. Three grade separations are under construction with another two grade separations and eight crossing safety projects in the design phase. Jump Start safety improvements have been completed at 40 at-grade crossings.