A series of overlapping bus agencies provide additional public transit coverage to Bay Area regions both served and not served by rail transit. The four largest agencies, Muni, AC Transit, SamTrans, and VTA operate within the City of San Francisco, East Bay, the Peninsula, and South Bay respectively, although their service areas generally overlap with neighboring agencies and numerous smaller agencies. All of these agencies also provide limited night bus service, which are intended to "shadow" the rail routes that are closed during the nighttime hours for maintenance. In addition, the four bus agencies are each independently pursuing constructing bus rapid transit systems by developing separated right-of-ways and traffic signaling on busy corridors, including on Geary and Van Ness for Muni, El Camino Real for SamTrans and VTA, and International Boulevard for AC Transit.