Roll-up doors have the advantages cited above, plus, if you are doing a city street delivery like in New York or Philadelphia, opening the door does not require you to step out into traffic, or to move the truck so you can clear a lamp post or street sign on the sidewalk side. It also keeps you from having to stop your truck in the middle of a busy street to open your doors before you back into a tight, indoor loading doc.
If you are doing an inside delivery from a city street, roll-up doors are a breeze to close and lock. That maintains the security of your freight and equipment while you are away from the truck and inside the building.
If you are working or exercising inside your reefer body in a temperature-controlled environment, roll-up doors are easier to manage when you are opening them from the inside to get out. You don't have to worry about the wind taking a swing door away from you and flying out of control.
In heavy winds during outdoor deliveries, a swing door can become dangerous if it slips out of your hands, and hard to work with if it does not.
In reefer trucks, roll-up doors do not seal as well as swing doors, but they seal good enough to protect the load. That pays HUGE dividends at pickups and deliveries. Say the outside temp is 100F and your reefer set point is 40F (or -10F for an extreme example).
With a rollup door, you back up to the dock and keep the door closed until the last moment before you load. That preseves much of the work your reefer did to get the truck down to temp before you arrived.
At a delivery, if they tell you to back up to the dock and wait, you can preseve temp with a roll-up door. With swing doors, you loose everything before you even bump the dock. If there is a delay in unloading you, a freight damage claim and dispute may result.
At loading, if the load is small enough, you can roll the door up, wheel the freight inside, close the door behind you, take your time securing the load while maintaining temp, exit the truck, and quickly close the door behind you again to preserve temp. In that case, a rollup door gives you the luxury of time to secure the freight and not making the reefer work any harder than it has to.
If your carrier or shipper requires you to be at the shipper-mandated set point before you leave the dock, trucks with roll-up doors will be long gone while trucks with swing doors will be still waiting to get back to temp.
About roll-up doors taking up space inside the body that could be otherwise used for freight, that is true. But, frankly, if the freight is that tall (and top-heavy), who really wants it anyway?
Our carrier specifies the door opening size for the trucks in its fleet. As long as you meet that spec, it makes no difference if you have a roll-up door or swing doors. Only on rare occasions would freight larger than the specified door opening be accepted to haul.
The once-in-a-year chance that might happen was not enough to forgo the everyday and certain advantages a roll-up door provides.
Oh yea. How many times a day do truckers nationwide tear the rollup doors off their or other drivers' trucks? That is a frequent event with swing doors. Next time you are at an indoor loading dock, look at the edges of the dock entrance. Almost always, you will see evidence of some driver catching his swing doors on the wall. We once saw an entire swing door laying on the ground just outside such an entrance. (Driver said, OOPS! :'( )
Also, when backing up to a dock, indoor or outdoor, swing doors reduce your visibility. Roll-up doors do not.
