For any streetlight geeks, one of the last Mn/DOT truss-arm installations in Minnesota is being replaced with davit poles, I-35W in the 98th Street area in Bloomington. This is the last continous lighting truss arm installation in the metro but a few exist for partial interchange lighting on I-35 south of town. Minnesota hasn't used truss-arm poles since the early 1960s; the I-35W installation lasted a bit longer because the underground was replaced reusing existing light poles in the mid 1980s when the interchange was rebuilt. Also the Hudson I-94 bridge has truss arm lights, presumably installed by Wisconsin.
I know Rhode Island also uses davit poles extensively, I kind of felt at home when driving through the state a few years ago.
Actually, there are quite a few truss arms still left along I-90 in outstate MN.