Listing the 20 most dangerous roads in the world with detailed information for each road is a massive undertaking, and the specifics might change over time due to road improvements, changes in conditions, and other factors. However, I can provide you with a list of some well-known dangerous roads along with brief descriptions. Keep in mind that this list is not exhaustive and is not ranked in any particular order.
North Yungas Road, Bolivia: Often called the "Death Road," it's a narrow, winding mountain road with steep cliffs and poor visibility.
Dalton Highway, Alaska, USA: This remote road is prone to extreme weather, ice, and isolation, making it challenging for drivers.
Kabul-Jalalabad Highway, Afghanistan: High risk of accidents due to reckless driving, poor road conditions, and security concerns.
Skippers Canyon Road, New Zealand: Narrow and winding with sheer drops, this road demands careful navigation.
Zoji La Pass, India: Located in the Himalayas, it's prone to landslides, avalanches, and harsh weather.
James Dalton Highway, Alaska, USA: Isolated and unpaved, it presents challenges such as rough terrain and long distances between services.
Tianmen Mountain Road, China: Features 99 hairpin bends up a steep mountain slope.
Guoliang Tunnel Road, China: Carved through a mountain, it's narrow and lacks guardrails.
Trans-Siberian Highway, Russia: Enormous length, challenging conditions, and isolation make it risky.
Patiopoulo-Perdikaki Road, Greece: Extremely narrow with hairpin turns, it's a test of driving skill.
Taroko Gorge Road, Taiwan: Carved through a rugged gorge, it's prone to rockfalls and landslides.
Stelvio Pass, Italy: A high-altitude road with numerous hairpin bends.
Col de Turini, France: Famous for its appearances in the Monte Carlo Rally, it's narrow and winding.
Sichuan-Tibet Highway, China: Extreme altitude, rough terrain, and unpredictable weather.
Le Passage du Gois, France: Floods cover this road twice a day, making it inaccessible during high tide.
Siberian Road to Yakutsk, Russia: Prone to freezing and thawing, causing uneven road surfaces.
Jalalabad-Kabul Road, Afghanistan: Challenging conditions due to security concerns and road quality.
Halsema Highway, Philippines: Landslides, fog, and narrow sections make this road dangerous.
Col de la Bonette, France: High altitude and narrow roads make it challenging.
Luxor-Al-Hurghada Road, Egypt: Desert road with high accident rates and minimal services.
Please note that road conditions and safety factors can change, and this list might not represent the current state of these roads. It's important to exercise caution and adhere to local guidelines and advice when traveling on these roads.