Why Snowplows Spread Salt in 40-Degree Heat

An image shows a snowplow spreading salt on a Dutch highway during summer to prevent asphalt melting.

Salt on Dutch Highways in Summer

Using snowplows to spread salt on highways in the summer might appear bizarre but is a planned maintenance protocol in the Netherlands. When temperatures rise above 40°C, the Dutch infrastructure agency employs these measures to safeguard the pavement.

Thermal Overload Risks

Rijkswaterstaat’s data reveals troubling patterns during summer heat. On main routes like Amsterdam to Haarlem, asphalt temperatures often surpass 50°C, leading to thermal stress, especially in high-traffic zones.

Roundabouts, on-ramps, and areas with frequent stops are particularly vulnerable. Tire friction can rip liquefied bitumen from the road, forming ruts and sticky tar that endanger vehicles at high speeds.

Salt’s Chemical Role

While water might seem an easy fix, it evaporates quickly. Salt, with its moisture-attracting properties, is preferred.

Salt pulls moisture from the air, forming a cooling layer on roads. It also absorbs excess moisture from bitumen, reducing stickiness. Authorities often mix salt with crushed sand to stabilize softened bitumen and prevent it from sticking to tires.

Photo credit: pexels-jan-van-der-wolf-11680885-24827190