The $24 billion project could cut travel time in half and improve air quality and traffic safety, Los Angeles County’s transit agency says.

Metro’s board approved a fully underground heavy-rail subway for the Sepulveda Corridor, aiming to cut Valley-to-Westside travel times and expand regional transit capacity.

Julie Sharp is a digital producer at CBS Los Angeles. She is a South Bay native and majored in print journalism at Cal State University Long Beach. Julie previously reported for the Beach Reporter, ...