I use the Joeysafe harness in taxi's (www.joeysafe.lenoirphoto.com) It is the only one I could find that is specifically designed to restrain kids in a car accident. It does require a seat belt though and is not suitable for young babies.
I thought the Joeysafe needed a seatbelt? Not usually available on buses.
I would have my baby in a sling or other baby carrier and choose a rear-facing seat if possible. And avoid the crazy speeding minibuses! A big solid bus must be much safer than a taxi or a minibus.
what do you mean rear-facing seat - on the bus you mean? yes, I agree with you a/b the minibuses-even on short routes.. I don't preferred them- much rather walk.. but now my choices for going out are limited.