It depends on where you are, and what you mean by reliable. Generally they're pretty good, particularly on more popular routes and between tourist destinations. Prices are set and you and your belongings will be pretty safe. Different kinds of vehicles are used, generally dependent on the usual volume of passengers, the distance to be travelled and the quality of the roads. These encompass everything from large VIP buses (just a marginally more modern bus than usual, often with air-con but not on the same scale as Thailand's VIPs) through smaller Chinese buses to trucks to songthaews of varying sizes and small jumbos which are really just overgrown tuk tuks.
Departure times are often dependant on the number of passengers; waiting until there are enough before leaving. Be sure to get on early to make sure you have a seat, as small plastic stools (or bags of rice) will be placed in the aisles for unseated passengers… which is better in turn than standing room only. The Lao idea of full to capacity is very different to the western one. Toilet stops on a bus will often be very brief and near a convenient clump of bushes by the side of the road. Longer journeys will be broken up at mealtimes with stops at roadside cafes, where the staple is either noodle soup or steamed rice with a selection of pre-cooked stir fry dishes to choose from. Vegetarian options are often limited, and if you're strict you should bring your own food.
Some larger journeys are joined together to make extremely long distances to travel (for example Vientiane to Luang Prabang to Sam Neua). One bus driver does the whole journey, perhaps stopping for a short nap on the way. Departure times will vary greatly, depending on how long the incoming leg has taken, and can sometimes be already full when it arrives.
Public travel, particularly on the more cramped songthaews, really gives an opportunity to get friendly with some locals and experience the Lao way of life.
Please find below some of the more frequently asked questions (FAQ) people have about travelling to Laos. We've tried to answer all the most frequently asked questions, but if you have another query about Laos, please try our Travelfish messageboard.
Is it possible to rent rooms or dormitories for longer periods of time while travelling in Laos?
Rooms: Is a fan room ok, or should I budget for air-on?
Should I take my own padlock for the door of my room while travelling in Laos?
What should I do if a bag is stolen from my room or dormitory while travelling in Laos?
What standard of accommodation can I expect for US$5 in Laos?
Why are there so few dormitories in Laos?
Why are there so few hostels in Laos?
Can I drink the tap water in Laos?
How can I avoid MSG in Laos?
How do I avoid peanuts in Laos?
I have a food allergy -- what should I do when travelling in Laos?
Is there good vegetarian food in Laos?
Is western food available in Laos?
Are credit cards accepted in Laos?
Are there ATMs in Laos?
Can I send money out of Laos?
How can I have money sent to me in Laos?
Should I bring travellers cheques, credit/debit cards or cash to Laos?
Should I tip in Laos?