She was pro-market, in many ways. She was mostly against top-down development that overrode people that were already in place (at the time it happened to be government ramming highways through cities using eminent domain). So in some ways she's "conservative" in that she likes property rights, less zoning, etc.

Urban left-leaning people tend to like her because she's very human-scale focused. Many use her anti-highway work to rally against other change (often private and market oriented. Though I love her work to death, I've found a lot of what most of us would call NIMBYs and champagne socialists cite her when opposing a lot of stuff (housing they don't like, etc).

This reason interview (libertarian org) outlines a lot of it: https://reason.com/2001/06/01/city-views-2/