Shipping personal items in a car during auto transport is not illegal. For these reasons, yes, you can. If the overall weight makes 100 lbs, we can have them in it free of charge during your car transportation, as long as they're neatly packed and stowed in the trunk or below the window level. If the weight exceeds the 100 lbs mark, extra fees may apply because now the shipment becomes heavier. However, we advise against it altogether.
The Federal Motor Carrier Safety Administration (FMCSA) oversees vehicle and personal items shipments separately. These rules aim to make carriers accountable in the event of specific property damage. Shipping car with personal items necessitates meticulously documenting each item on the Bill of Lading (BOL), which does not happen. In other words, auto transport carriers are exclusively responsible for carrying cars. Anything wrong transpires with the personal items in the vehicle won't be subject to a claim. Firstly, you will not have anything documented on BOL to prove their initial condition, and secondly, if they go missing, you won't be able to show they were there in the first place.
Separate property regulation is, indeed, a sensible concept for a variety of other reasons. Because the securement standards for each sort of cargo differ, combining them further complicates matters.