From what I get from skimming the paper he suggests that America's focus on cars might be related to the end of segregation, with cars allowing white people to just decide to live in a neighborhood with few black people. Effectively the policy shift towards cars enabled a new form of segregation.

Additionally "Experiments have found that motorists yield less often for people of color." (page 27).

But those are minor tangents in a 100 page rant about laws and enforcement (as well as victim blaming in traffic accidents)

Something of a secondary effect really, but the two things that immediately come to mind are "nonwhite people are less likely to afford cars" and "nonwhite people are more subject to discriminatory traffic stops that (in the US) sometimes escalate to lethal violence".

In general, highway infrastructure was routed through minority neighborhoods to bulldoze them to the ground.

Today, poor minorities get forced to live in the lowest value land, which is usually right alongside major roads. The lack of safe pedestrian facilities means that these neighborhoods have higher levels of pedestrian fatalities: https://www.inverse.com/amp/article/26210-pedestrian-deaths-...

Because they live alongside major roads, they also suffer from higher rates of respiratory disease from air pollution. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4454972/

> Cars are less likely to stop when people of color step into intersections, a study says.

https://www.npr.org/2017/02/15/515336658/researchers-examine...

Traffic stops by police leading to fatal or seriously bad outcomes (jail, property seizure).

You could also attempt to clumsily extrapolate PoC to mean "high crime neighborhood" or historically segregated/red-lined communities which would mean higher insurance rates or other ownership costs (parking, towing).