Many cities in snowy parts of the country are switching from sodium chloride (rock salt) to brine, a solution that contains magnesium chloride. The brine solution is cheaper, easier to apply and is gentler to paved surfaces. In these cities – where the freeze-thaw cycle creates potholes by shrinking and expanding the pavement – sodium chloride exacerbates the road damage by further eroding the holes in the road. Magnesium chloride doesn't really affect the fissures in the road's surface and there is less waste when it's applied, making it more economical.
While this is great news for the roads,it's bad news for drivers. Magnesium chloride may be gentler on pavement, but it's rougher on cars.