In our office because of the shared van duties and the single driver duties means that at least over half of our workforce must be able to drive. Also, when the duties need covering by reserves or for overtime they usually need people that can drive the vans.
Apart from the fact that being a non-driver takes away some of the responsibilities of the job. For example, they are not really responsible for delivering the large packets and/or specials (they are supposed to have a bigger loop to deliver instead - though I would testify that they are pretty much the same). And some of the lucky ones get dropped off at home whilst the driver has to come back to the office with all the bags and packet returns, and occasionally, having to face a firing squad of managers waiting to see how many tracked items you brought back either
The few indoor staff at our depot that can't drive never get sent out to cover any deliveries either. They just make their way down to the callers office while the managers do it.....