One of the firm principles of the road department of the City of Portland is that it will maintain city streets only after a developer or the neighbors bring them up to city standards. This is why southwest Portland has so many dirt and gravel roads -- they're old county roads that were brought into the city without having been properly widened and paved, and it's up to the adjoining owners to maintain them until they're willing to dip into their pockets, form a local improvement district, and pay to add the curbs, sidewalks, and storm drains.
One of the substandard streets of southwest Portland is SW Highland Road. It's a curious street that runs from SW Canyon Court near the Children's Museum north up the hill to SW Fairview Boulevard, near Hoyt Arboretum. Most of the houses on Highland Road are in unincorporated Multnomah County and aren't assessed city property taxes, but most of the road itself has been annexed by the City. Willamette Week ran a story on this curious city street in December 2006.
I recall reading not long ago that the City is about to repave Highland Road. What I don't know is whether the City ever accepted Highland Road as being improved to city standards. If the City isn't maintaining SW Alice (say) or SW Primrose because the neighbors haven't paid to bring them up to city standards, then it shouldn't be maintaining Highland Road until the residents pay to widen the road and bring it up to city standards -- not unless there's a double standard for the roads of the rich.