Transport should always be carried out with the dewar upright and secured against lateral movement. Even brief tilting of a liquid-nitrogen-filled vessel can cause nitrogen to escape rapidly through the neck, creating an asphyxiation hazard in enclosed vehicles. Cryolab dewars are designed with low evaporation rates and wide, stable bases. For road transport, purpose-built transit crates with foam cradles are strongly recommended, and oxygen monitors should be present in any vehicle carrying active dewars.