8 ms·

Sand isn't all that useful at temperatures near freezing- as the snow / ice melts a bit in the sun, it sinks in, and you end up with fresh glaze as it cools and

Sand isn't all that useful at temperatures near freezing- as the snow / ice melts a bit in the sun, it sinks in, and you end up with fresh glaze as it cools and refreeze. Using salt or similar to completely melt the cover allows it to drain off the road or sublimate, leaving the road dry.

bradfa 6y ago
Yeah, and I'd like to see a scientific study about this to show how it works and so people can understand it. A significant amount of money is spent on clearing and treating roads during wintry weather, I think it would be very beneficial to understand why taxpayers spend this money and what they get in return. Additionally, if information such as "winter tires are X% better at stopping/turning than all season tires when treating roads with Y" could be presented, then maybe more people would opt to purchase winter tires (or maybe the opposite) depending on what types of solutions the local government uses.
- nemo44x 6y ago
  Why tax payers spend the money: so roads are safe to travel on. What they get: safe roads to travel on. I don’t think we need a study here.
- zdragnar 6y ago
  A brief google search brought up a PDF for winter tires from the traffic injury reduction foundation, with the basic conclusion that yes, they are better, but updated studies are needed for exact numbers. Walk into any car tire store, and you will see displays for winter tires claiming anywhere from 25-35% improved stopping distance. Of course, with less frequent plowing, salting and sanding, these numbers likely go out the window. They get you better stopping distance, but they aren't magic and it is still worse than all season tires on a dry, summer road. If you want safer winter roads, you use salt and / or sand and plow every time significant accumulation of snow occurs.
  - destitude 6y ago
    I drive on unplowed paved roads and I can tell you from first hand experience that there is a world of difference between snow tires and all season tires. The chemistry of the tire itself is different. All season tires start getting hard around 40F whereas snow tires stay soft/rubbery below 40F and colder. This is fundamentally why snow tires are superior for snowy/icy conditions. This is also why you should not use snow tires in summer because they will wear very fast due to the composition being soft.
frosted-flakes 6y ago
The use of sand also requires extensive street cleaning each spring. Lots of the sand gets recovered, and is presumably re-used.
- lstodd 6y ago
  Reused? Ha-ha. Just swept somewhere out of sight. Which is much better than the salts, because sand is mostly neutral, while salts, esp slow-dissoving stuff kills plant life long after the season ends.
  - frosted-flakes 6y ago
    Well, it's collected, and if they already have it in a dump truck, why wouldn't they re-use it? In the spring, the street cleaner cleans my whole street, and dumps each load at the dead-end. Later, it gets loaded into a dump truck and taken somewhere (3-4 dump truck loads in total, estimated). The last few years they've used sand a lot more sparsely (only on intersections and hills), so I'm pretty sure the street cleaner only picks up one load and can carry it away without needing a dump truck.
- throwawayboise 6y ago
  It's not re-used. It goes to a landfill. There's too much street garbage mixed in by the time they sweep it up in the spring.
  - frosted-flakes 6y ago
    Sounds reasonable. But even as landfill I bet it gets reused as cover.
nend 6y ago
Maybe, but worth noting that both Vermont and Colorado (maybe more), have banned the use of salt on roadways due to environmental concerns. So to ops point, there are alternatives to using salt, even with near-freezing temperatures.
- sigstoat 6y ago
  > So to ops point, there are alternatives to using salt, even with near-freezing temperatures. in my experience here in colorado, the most commonly chosen alternative is "do nothing". they dump the gravel/sand stuff out sometimes, but then it just accumulates near intersections, reducing traction in dry weather until the end of spring when they go sweep it off the sides of the roads.
Broken_Hippo 6y ago
Around here, they use grit instead of a fine sand. It doesn't matter as mcuh if there is a melt and freeze cycle. Since the grit is around the size of a pea, it leaves textured ice. Don't get me wrong, you can still slip and fall, but I can catch myself more often and tires seem to do well enough.
- zdragnar 6y ago
  We get a mix of grit and sand at intersections and steep hills, but it only lasts just so long- sand disappears and grit gets kicked off the road. It certainly beats salt alone, especially on a hilly gravel road and sharp turns and intersections, but I wouldn't advocate for it as a complete replacement.

bradfa 6y ago

Yeah, and I'd like to see a scientific study about this to show how it works and so people can understand it. A significant amount of money is spent on clearing and treating roads during wintry weather, I think it would be very beneficial to understand why taxpayers spend this money and what they get in return. Additionally, if information such as "winter tires are X% better at stopping/turning than all season tires when treating roads with Y" could be presented, then maybe more people would opt to purchase winter tires (or maybe the opposite) depending on what types of solutions the local government uses.

nemo44x 6y ago
Why tax payers spend the money: so roads are safe to travel on. What they get: safe roads to travel on. I don’t think we need a study here.
zdragnar 6y ago
A brief google search brought up a PDF for winter tires from the traffic injury reduction foundation, with the basic conclusion that yes, they are better, but updated studies are needed for exact numbers. Walk into any car tire store, and you will see displays for winter tires claiming anywhere from 25-35% improved stopping distance. Of course, with less frequent plowing, salting and sanding, these numbers likely go out the window. They get you better stopping distance, but they aren't magic and it is still worse than all season tires on a dry, summer road. If you want safer winter roads, you use salt and / or sand and plow every time significant accumulation of snow occurs.
- destitude 6y ago
  I drive on unplowed paved roads and I can tell you from first hand experience that there is a world of difference between snow tires and all season tires. The chemistry of the tire itself is different. All season tires start getting hard around 40F whereas snow tires stay soft/rubbery below 40F and colder. This is fundamentally why snow tires are superior for snowy/icy conditions. This is also why you should not use snow tires in summer because they will wear very fast due to the composition being soft.

frosted-flakes 6y ago

The use of sand also requires extensive street cleaning each spring. Lots of the sand gets recovered, and is presumably re-used.

lstodd 6y ago
Reused? Ha-ha. Just swept somewhere out of sight. Which is much better than the salts, because sand is mostly neutral, while salts, esp slow-dissoving stuff kills plant life long after the season ends.
- frosted-flakes 6y ago
  Well, it's collected, and if they already have it in a dump truck, why wouldn't they re-use it? In the spring, the street cleaner cleans my whole street, and dumps each load at the dead-end. Later, it gets loaded into a dump truck and taken somewhere (3-4 dump truck loads in total, estimated). The last few years they've used sand a lot more sparsely (only on intersections and hills), so I'm pretty sure the street cleaner only picks up one load and can carry it away without needing a dump truck.
throwawayboise 6y ago
It's not re-used. It goes to a landfill. There's too much street garbage mixed in by the time they sweep it up in the spring.
- frosted-flakes 6y ago
  Sounds reasonable. But even as landfill I bet it gets reused as cover.

nend 6y ago

Maybe, but worth noting that both Vermont and Colorado (maybe more), have banned the use of salt on roadways due to environmental concerns. So to ops point, there are alternatives to using salt, even with near-freezing temperatures.

sigstoat 6y ago
> So to ops point, there are alternatives to using salt, even with near-freezing temperatures. in my experience here in colorado, the most commonly chosen alternative is "do nothing". they dump the gravel/sand stuff out sometimes, but then it just accumulates near intersections, reducing traction in dry weather until the end of spring when they go sweep it off the sides of the roads.

Broken_Hippo 6y ago

Around here, they use grit instead of a fine sand. It doesn't matter as mcuh if there is a melt and freeze cycle. Since the grit is around the size of a pea, it leaves textured ice. Don't get me wrong, you can still slip and fall, but I can catch myself more often and tires seem to do well enough.

zdragnar 6y ago
We get a mix of grit and sand at intersections and steep hills, but it only lasts just so long- sand disappears and grit gets kicked off the road. It certainly beats salt alone, especially on a hilly gravel road and sharp turns and intersections, but I wouldn't advocate for it as a complete replacement.