[Seruzawa]

I-15 is 80MPH from just south of Provo almost to St George on the Nevada border. But in a sand storm you slow down pull over and shut off the engine. It’s a good way to clog your air filter if you keep running the engine.

[Vigilanteman]

No argument on slowing down and pulling over. You just don't slam your breaks as is the knee-jerk reaction or so many urban drivers trained to deal with traffic and not with nature.

Slow down gradually, drop a gear or two, put on the flashers and look for a safe place to pull over.