My truck kit has minimal cold weather gear because it's just not necessary here. That said, for road trips, I take an extra duffel bag which has blankets and other gear just for winter in the mountains.

It does not require high latitudes and an arctic blast to shut down roads. Even in SOCAL winter travel can get dicey. On a trip back from LV, I-15 at El Cajon Pass (el 4000') was closed due to wind, snow ice, wind ... played real havoc with the big rigs. We just pulled off and waited it out in a strip mall parking lot. It is so much better for your vehicle and your nerves. Pull over, get out a fleece blanket and catch a little needed rest. Way better than sitting in traffic that's not moving.