John is a County Commissioner. I think there are four of them in Texas Counties and a County Judge is also a part of the group for a total of five members. With five votes there can never be a tie vote on a county wide subject.

His job is to take care of the roads and bridges that are not in a city but are still in the county, but only if it is in his district.

There are still parts of Dallas County that are not part of a city. Mostly flood zones and such that no city wants because they don't want to have to maintain the roads in an area that will never develop.