Absolutely! This scenario can work well. Unlike restraining Rex behind you, the two of you ride side by side. Larger breeds can benefit from having the extra space. This area allows pups the freedom to change positions.
Sidecars can be a great addition for pup parents but expect a learning curve. Going from two wheels to three can be an adjustment. Consider taking a course on driving with sidecars. As your confidence and comfort increase, so will safety.