In general, bus transport is well developed throughout the continent. Note that road conditions, bus quality and driver professionalism vary widely. Much depends on the season: vast deserts of red dust in the dry season become oceans of mud in the rainy season. In Argentina, Uruguay, Ecuador, coastal and southern Brazil, and most of Venezuela, roads are generally better. Chile and much of Argentina have some of the best-maintained roads and most comfortable and reliable bus services in South America.
Most major cities and towns have a terminal de autobuses or terminal de ómnibus (bus terminal); in Brazil, it's called a rodoviária, and in Ecuador it's a terminal terrestre. Terminals are often on the outskirts of town, and you'll need a local bus or taxi to reach it. The biggest and best terminals have restaurants, shops, showers and other services, and the surrounding area is often a good (but frequently ugly) place to look for cheap sleeps and eats. Village 'terminals' in rural areas often amount to dirt lots flanked by dilapidated metal hulks called 'buses' and men hawking various destinations to passersby; listen for your town of choice.
Some cities have several terminals, each serving a different route. Sometimes each bus company has its own terminal, which is particularly inconvenient. This is most common in Colombia, Ecuador and Peru, especially in smaller towns.
Especially in the Andean countries, buses may be stripped nearly bare, tires are often treadless, and rock-hard suspension ensures a less-than-smooth ride, particularly for those at the back of the bus. After all seats are taken, the aisle is packed beyond capacity, and the roof is loaded with cargo to at least half the height of the bus, topped by the occasional goat or pig. You may have serious doubts about ever arriving at your destination, but the buses usually make it. Except for long‑distance routes, different classes often don't exist: you ride what's available.
At the other extreme, you'll find luxurious coaches in Argentina, Brazil, Chile, Colombia, Uruguay, Venezuela and even Bolivia along main routes. The most expensive buses usually feature reclining seats, and meal, beverage and movie services. Different classes are called by a variety of names, depending on the country. In Argentina, Chile and Peru, the deluxe sleeper buses, called coche-cama or bus-cama (literally 'bus-bed') – or leito (sleeping berth) in Brazil – are available for most long-distance routes.
In the Andean countries, bus rides generally add up to about US$1 per hour of travel. When better services (such as 1st class or coche-cama) are offered, they can cost double the fare of a regular bus. Still, overnighters obviate the need for a hotel room, thereby saving you money.
Prices elsewhere average about $2 per hour, but can vary considerably within countries. Prices are highest in French Guiana (around $5 per hour).
It's always wise to purchase your ticket in advance if you're traveling during peak holiday seasons (January through March in the Cona Sur; and around Easter week and during holiday weekends everywhere). At best, bus companies will have ticket offices at central terminals and information boards showing routes, departure times and fares. Seats will be numbered and booked in advance. In places where tickets are not sold in advance, showing up an hour or so before your departure will usually guarantee you a seat.
Anyone who has done their share of traveling in South America can tell you stories of horrifying bus rides at the mercy of crazed drivers. And there are occasionally accidents. Choosing more expensive buses is no guarantee against accidents; high-profile crashes sometimes involve well-established companies. Some roads, particularly those through the Andes, can be frightening to travel. A few well-placed flights can reduce bus anxiety.