This suggests the burden of rock salt (which speeds up corrosion of cars) would fall more on people with higher incomes, because they are more likely to drive cars than people with low incomes.

It’s not clear how this relates to use of rock salt on roads. Road maintenance generally may disproportionately burden people with low incomes, but we have no reason to think using rock salts on the road would require more maintenance than not using rock salts.

It’s not clear how the cost of cars relates to the burden of usin rock salts on the road.

We’re told that rock salt on the road speeds up the corrosion of automobiles. Although the city claims that cars today are better protected against rock salt than they were five years ago, if people with low incomes are more likely to buy older vehicles, they’ll be less likely to benefit from those protections than people with high incomes. This helps us establish that the rock salts on roads will disproportionately harm people with low incomes compared to people with high incomes.

This suggests the burden of rock salt (which speeds up corrosion of cars) would fall more on people with higher incomes, because they are more likely to drive on roads treated with de-icing agents than people with low incomes.