Just got back from Yosemite and Tahoe National Parks - lots and lots of snow. + The ease of putting them on is amazing, can take 2 minutes max and you can't screw anything up, they work really well. CalTrans looked at them and they let me go but had doubts that they worked well - I was very very careful never to exceed 30mph however snow/ice conditions are rare, often is the road a mixture of snow and asphalt. Asphalt wears away the fabric and creates holes. In very cold conditions, the fabric freezes through and it is very difficult to remove the socks as the fabric has hardened. Avoid rocks, potholes and tire slippage at all costs. Conclusion: After 5 days of continuous wear, they wear out, even when driving less than 50 km/h.