Once you've packed a toothbrush, underwear and other necessities, you're ready to see the country and put some domestic miles under your belt. Does a photo ID need to be packed in your essentials as well? Some modes of transportation have cracked down on security and now require one, while the notoriously tight security screeners at the airport have an alternative for adults traveling without an ID card.


The Transportation Security Administration requires that all passengers 18 years of age and older flash a photo ID to board all flights, foreign or domestic. This includes a driver's license, permanent resident card, international or U.S. passport, "trusted traveler" card from the Department of Homeland Security, tribal ID and other official forms of identification. But as strict as the TSA is about its travel rules, you may be surprised to know there's a safety net for those who forget a photo ID. Let the screener know, and you'll be asked to answer a series of questions checked against public databases to verify your identity. However, if these answers don't satisfy security screeners, you won't be let through to your flight.


Photo identification isn't required when using local subway systems in large cities. But when traveling beyond city limits on Amtrak you'll need an ID. The nationwide rail operator requires photo ID for passengers 18 years old and up when obtaining a ticket, checking or storing baggage and sending shipments via Amtrak. As part of heightened security, train staff also conduct random ID checks up and down the passenger cars. To buy a ticket you need to be at least 16 years old and show photo ID. Valid forms of identification include a driver's license, passport, student ID card or military ID.


To travel on a bus within a metropolitan area, all you need is a schedule and fare. To ride to locations far and wide across the U.S., you'll need photo ID for a ticket on Greyhound. The bus service offers ticket purchases online, over the phone, at the terminal or through a Greyhound agency. Whether you print a ticket on your home computer or pick it up at the Greyhound counter, you'll have to show a photo ID. Though a password can be created for a passenger to use for ticket pick-up, identification is necessary before boarding.


Naturally, you need a driver's license to rent and operate a car. But what about the stops along the way if you decide to embark on a road trip? Requiring photo ID to check in at a hotel depends on the state or city, and if they have no laws in the books one way or the other it falls upon the proprietor to decide what's required to stay there. Justifications can vary from security reasons to streamlining the paperless check-in process and needing ID verification to replace the registration card you might otherwise fill out. If you'd rather pitch a tent for the night, national parks will require photo ID for discount pass holders and for some mountain climbing. Private campgrounds may set their own rules.