Do you like to exercise whenever you get a free moment? If so, you will probably have a trusty bike at your disposal and like to take this with you when you go on a trip, if possible. Perhaps your significant other enjoys the same hobby and also has a bicycle to consider, so you need to work out how you're going to transport these machines when you go away on your road trip. What are your options?
If you have a standard car, then you have two choices. You may be able to fit both bikes to the rear by using a tow bar attachment, but in most cases you should consider adding them on top, as this will be more practical.
On the Back
Some people are not happy fitting their bicycles to a rear-mounted carrier because it makes it more difficult for them to drive. They may not be able to see out of the back window clearly and may need to resort to using side mirrors instead. Furthermore, a rear carrier can be challenging to configure, and you need to avoid loading your bikes incorrectly. If they "stick out" beyond the outline of your vehicle, then they could present a risk to other vehicles or to pedestrians. Furthermore, you may block the rear number plate or your brake lights if you're not careful, and this could land you in trouble.
In most cases, it's better to consider a roof mounted carrier that is attached to your roof rack. You'll be able to fit two bikes on there with no problem but should pay attention to how they are mounted. Make sure that you use bungee cords or other secure straps so that they are carefully tied down. The front wheel must also be secured, as otherwise it will have a tendency to turn by itself.
Make sure that you load the bikes so that they sit in a straight line from front to back. Otherwise, they will present additional drag, and this will adversely affect the handling of your vehicle while adding to your fuel bill.
Before you set off, make sure that you check the security of the roof rack, the bicycle carrier and the bikes themselves and tighten any attachments as needed. If you're in an unfamiliar area, be aware that your vehicle is now a lot taller than it used to be, so watch those parking garages or bridges with low headroom.
Always buy the best quality roof racks and bike carriers on the market so you arrive at your destination ready to roll.