Robert Jueneman said:
The short answer is NO. If the Nitrogen should leak out - maybe the Dewar could fall over if you are involved in an accident the nitrogen will boil quickly to make nitrogen gas and this will displace the air in your car and you will suffocate - not a good idea. You can transport liquid nitrogen either in the boot (US trunk) of the car only if it has a separate sealed bulkhead - not in a car with fold down rear seats. It is best to use a van (US truck) with a sealed rear compartment or a trailer. You should inform your insurers that you will be transporting liquid nitrogen (otherwise you may find your insurance is invalidated) and you should display a cryogen in transit yellow warning sign.