Public transportation is quite good in Salvador and will no doubt be improved, at least for the local residents, when the metro service finally (????) opens.
Buses:
The buses are relatively cheap (R$2.20), clean and usually run frequently to the more popular destinations. Generally speaking you don't have to wait long for a bus, except on holidays or Sundays. Some buses, including the route from Pelourinho to Porto da Barra, stop at 11 p.m. Others run all night, although more infrequently, or stop at 1 a.m. Using the bus has the added benefit of giving the visitor a glimpse of ordinary people's lives. For the main tourist destinations, accessing a bus is relatively easy, although the nature of Salvador's layout can make it a little disorienting for a first time visitor. Be aware that during Carnaval, many buses are re-routed to avoid the main Carnaval circuits.
Buses in Salvador are entered from the rear and exited from the front and you pay when you get on. Have your money ready to present to the fare taker as you enter and pass through the turnstile. S/he can make change for small bills (up to 3 times the fare). There are seats at the front, which are allocated for the elderly and infirm; always give up the seat to them. It's worth noting that it is a custom in Brazil for seated passengers to offer to take bags and hold them for other passengers who are standing. Don't be alarmed if someone gestures toward your bag or offers to put it on their lap.
The small executivo buses are air conditioned, but cost roughly twice the price of a regular bus (R$4,80). Sometimes the ac is well worth the extra money, but can also get very cold. You get on these mini-buses in the front and pay as you exit, or when the fare taker comes around to collect money.
Routes:
For most tourists, staying in either the Centro Historico or the Barra area, the bus to and from is an uncomplicated affair, with buses running from Rua Chile near the Elevador down to Barra and also through to the airport. Conversely, buses from Barra run up via Campo Grande, along Avenida Sete to the same spot. Some buses take another route and end up in front of the mall Shopping Barra, from where it is a short walk along back streets to Porto da Barra beach.
To access Bonfim from the tourist neighborhoods, it's probably easiest to take the Elevador Lacerda down to the bus stop at the bottom, opposite the Mercado Modelo. The bus stops almost directly outside the entrance to the Elevador and is marked Ribeira or Bonfim. If you are staying at the Santo Antonio end of the Pelourinho, you can also take the plano inclinado down to the Commercio and board a bus on Av. Jequitaia. Buses marked Bonfim or Ribeira also pass the Mercado São Joaquim, a large, open-air produce market which visitors may wish to visit. For those wishing to explore a little further afield, there is a major bus terminus behind Shopping Lapa that services many routes. Those wishing, for example ,to travel up the coast to beaches like Guarajuba find that buses depart from here and out on Avenida Vale de Tororó, although the latter isn't the most salubrious spot and is ill advised at night.
Cars:
Parking can be a nightmare in Salvador and as already noted, the layout of the city with its twists and turns can confuse someone not familiar with the topography. Many streets are one way only. For that reason, hiring a car is not really a particularly sensible option for the visitor. Also, if you are contemplating hiring a car for trips out of town, exiting the city, especially in certain directions (for the Reconcavo through Sete Portas, for example), can be confusing. Good city and state maps are often sold on the street, across from the Elevador Lacerda.
Your hotel or pousada probably has a rental agency that they can recommend. Usually (except at holidays or other heavy rental periods) the car can be delivered to your hotel. At drop-off, you can also sometimes ask to have the agency representative pick you up at your hotel and take actual return of the car at the airport, saving a taxi fare. Rates (with recommended insurance and unlimited miles are about R$90 per day ,as of 8/08)