Once final and active labor starts can I take tylenol (acetaminophen) on the way to the hospital ?

Check with OB first. Please check with your OB md first before aking anything while in acitve labor. Many medications that may be given in acitve labor at the hospital have a synergistic (combined) effect when taken together that is greater than when either medicine is taken alone. So please check first.
Yes. Make sure to tell your caregivers on arrival. If they give you any oral pain rx, you may recieve more Acetaminophen and there is a safe limit to follow.