Is brine more corrosive than rock salt?

If an agency is using rock salt to its best advantage, it is employing brine. So, rock salt and brine are just two sides of the same coin. That said, yes, chlorides can cause corrosion in metals, and if not treated properly this can cause damage to vehicles and infrastructure. Some organic additives may have corrosion-resistant benefits. Certainly, laboratory studies show that some of the organics reduce corrosion substantially. However, the best way to reduce or avoid corrosion is to take the extra precaution of rinsing off any residue from the road salt or the brine the road salt has become.

Source: https://professionalsnowfightersassociation.org/wp-content/uploads/2019/04/16PUB_BrineFactSheet_Spring2016_FINAL1-copy.pdf