If you are moving large items in your truck and the flatbed is filled past its top you of course are going to use a number of truck tie downs to manage the load safely. Similarly if in your car or van you decide to use the roof rack to transport a large item you will likely have it well- strapped in with a series of ratchet straps and winch straps. Luckily these load binders are durable and likely to survive main streets, bumpy roads, and even steep hills. That said, all of the above should still be avoided if possible.
Finding the smoothest route to your destination when carrying cargo is a cautious move that can save you money and aggravation. The general stress of say driving on a busy street while hauling a large piece of furniture on the roof of your car is enough reason to try and find an alternative trajectory.
Of course should you end up having to get a couch up a hill or a new dining room set over a bumpy road the right load binders should be able to properly assure you of their safety. That said if the risk can be avoided it probably should be.
