For whatever reason, there are times when companies try to dictate the route that their PA freight service is going to take in order to make their deliveries. There are times when this might be acceptable and times when it is not but usually, unless you are paying for a dedicated courier or a full truck load shipment, you aren't going to get too much input into which route your courier takes. This is because there is actually a great deal of planning and forethought that goes into the routes taken by couriers on the part of the courier company themselves. They try their best to make sure their drivers are taking the most efficient routes, as this allows them to make cheaper runs, and thereby charge less to their customers.
Typically speaking a courier is going to not just be making your delivery, but also many others along the same route, and will likely have his route uploaded to his vehicle via a GPS system. Usually, they stick to these routes. What you can dictate is how long you want to wait for your package to arrive (with the cost rising with faster delivery times) and they will select the best
route to make that happen for you, at the best possible cost to your company.
There are times though when you are going to be able to dictate the route that your driver takes, and it really all comes back to the actual service that you have chosen to purchase. If you, for example, have selected a point to point or rush delivery option, you may be able to tell them what route to take because there are not going to be any other shipments in the vehicle.
Many businesses also subcontract a dedicated delivery driver from a courier company. These are the people can, will, and should tell their delivery drivers where to go, because they are the only company that they are working for. This is a service used primarily by companies that have constant shipping needs throughout the day, such as a flower delivery service. Sometimes it can be to their advantage to dictate the route to complete orders in a certain order even if that isn't the most logical or direct way to complete the deliveries, but as they have contracted the driver for the entire day they can choose to send them wherever they wish.