I’ll run by the laws in a minute but MOST imlattonrpy the laws of physics are the same, whether in a taxi, bus, or personal vehicle. You’re child will still be inured and/or killed in an accident. It is not more safe b/c she will be 3, nor is it more safe b/c its a taxi or bus. And a 3 year old has no business being in a booster seat, so you will need to bring a car seat along to protect your child. At 3, if you are flying, she should also be in a seat on the plane.Depending upon her height and weight at that time, I’m sure there will be many options for you guys. The easiest seat to install over and over again is the Britax Marathon, b/c of the built-in lockoffs. Goes in almost every car easily, and you can attach a gogoKidz so you can even put your child in it and wheel it around like a stroller when you are walking so you don’t have to carry it. Alternatively, you could rent a car, and install the car seat once and only once for the duration of your trip. However, do NOT rent a car seat! Used car seats are not safe! If you wouldn’t trust the rental company with your child’s life, don’t do it. Becuase in actuality, it is all the previous renters who you are entrusting with your precious baby’s life. Car seats will not protect a child correctly if they are:expiredwreckedhave been droppedthe straps have been saturated and washed If she’s small enough at that time, grab a Cosco Scenera, $50 at Walmart/Target (pretty pink cover, too!) It’s lightweight and pretty easy to install.OK on to the law. By Florida law, children 3 and under MUST be restrained in a 5 point harness in all vehicles excluding public buses. So, if you’re going to take a taxi, its a good bet that taxi driver is going to require you to use a car seat so he doesn’t get into trouble, I would think. And I wouldn’t use any seat a taxi driver would provide. There would be no telling the history of the seat.