RapidPlan and RapidPlan Online are both used for drawing traffic control plans, but they are different products.
The product best suited your needs depends on the complexity of your plans and the frequency you produce them.
RapidPlan is a desktop application. It’s full featured software, ideal for producing plans regardless of their level of complexity.
RapidPlan Online is a web-based application, ideal for small-to-medium businesses with the occasional need for plans of low-to-medium complexity.