Battery backup systems (BBS) are equivalent to a UPS that keeps traffic signals running for two or more hours after a power failure.   The photo shows a Type 332 controller cabinet (typical installation on a Caltrans highway) and the somewhat smaller cabinet on the right is the BBS.  BBS started seeing interest in California about 2001 when the state had an unusually high number of brownouts.   BBS started getting deployed in greater numbers in about 2004 after a CPUC study documented their b...
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