The road network is limited by North American and European standards, but expanding and improving all the time. Less than 15 percent of the highways, however, are paved so expect a bumpy ride if you're going on any but the most important routes. The Panamericana (Pan American Highway) forms the backbone of the country's road infrastructure, linking all the major highland towns and cities from Tulcan to Loja. A handful of other good roads spill down the Andes to important coastal cities such as Guayaquil, Manta and Esmeraldas, while in the Oriente the road system is the least developed and exists almost entirely to serve the needs of the local oil industry. The network's biggest problem has always been the weather - floods and landslides are common - while the rough nature of the terrain means that travelling in the country's highland and mountainous regions is often much slower than you might expect: travelling the length of the country by bus from the Colombian border to Peru, a distance of 818km on mostly paved roads, takes around 18 hours - an average speed of 45km.