Conducting inventories of towed or seized vehicles
When SCOTUS disallowed searches incident to arrest where the driver was restrained and away from the vehicle, some agencies and officers overcompensated by failing to use other theories to keep them safe from unexamined vehicles.
It is important to remember that vehicle inventories are not searches. Inventories are not purposed to gather evidence, but to protect the officer's integrity and any valuable property in the vehicle. There are many occasions when an officer opts not to have an arrestee's vehicle towed, but most department policies and forms are for inventories on towed or seized vehicles.
A visual inspection of the interior of the vehicle should be done even in cases where it is not seized. What a tragedy if a sleeping child were left behind!
Arrestees should give some recorded affirmation that nothing of value is in the vehicle if they are the owner. If they are not the owner then you owe it to the owner to inventory the vehicle left parked to ensure the safety of the contents.