This is a portable sign used at a school crosswalk. Its inelegant method of storage contrasts with its more noble posture when in use (see previous photo).
I saw this while riding my recumbent trike in Maricopa and photographed it while sitting on my trike.
The dark ground behind the sign is a grassy drainage swale, one of many in Maricopa. The railing stands atop a concrete conduit that diverts water from the street into the swale.