Yes, it is generally safe to sleep in your car in Alaska, as long as you follow certain precautions and guidelines. Make sure to park in designated camping areas or RV parks, and be aware of the weather conditions, as temperatures can drop significantly at night. It's important to have proper sleeping gear, food, and water supplies, as well as a plan for restroom facilities. Additionally, be cautious of wildlife, such as bears, and store food and scented items securely. You can find some suitable locations for car camping in Alaska on Hipcamp, such as Safety Cove, Sealion Cove, and Sunny Cove.