Don’t use “public transportations” (with an “s”).
Just use “public transportation” (non-count).
If you want to turn it into a countable noun, try something like “public transportation systems.” Or even “public transportation options,” depending on the context.
Like this:
“I always use public transportation to get around.”
“Most cities want to improve their public transportation systems.”
“There are a lot of public transportation options for commuters in my town.”
I see this error quite frequently since the independent essay can often be written using personal examples about going to work or school.