Certainly looks like it could be walnut. Lots of county crews don't really care what it is if it's in the right-of-way and causing issues. Most of the times the trees are rather mis-formed due to years of being cut back and abused. My county crew like to take a rotary mower on a hydraulic boom and literally mow the branches back. Looks like hell and is not good for the trees....but it does the job and seems to be efficient and that tends to be all they are interested in.