A good place to start with similarities is the basic setting. Both stories take place in the United States in a future, post-apocalyptic world. There is no identifiable government or law enforcement in place, and people have been forced to band together in small groups in a survival of the fittest type mentality.

Other similarities can be found through thematic examination. Both future worlds are in a bad state. Things appear hopeless, and the protagonists seem to always be fighting against, and succumbing to, general hopelessness. Despite that, the characters in both The Road and The Walking Dead do cling to the idea that a better world or hopeful state is just "beyond the horizon." For the Man and the Boy, their hope is quite literally beyond the horizon. That is why they are walking. In The Walking Dead, there is hope for a possible cure or larger populations that have not been affected by the zombie outbreak.

The characters in both stories have to have this hope because without it, there would be a complete loss of humanity. The Walking Dead will have a loss of humanity if the zombies win out or if each enclave begins falling apart from the inside. The Man and the Boy fight to maintain their humanity in a world that is almost devoid of people; the people that are left have resorted to cannibalism and barbecuing babies. Both stories have a theme of isolation, too. It's a lonely existence to be among the only living (non-zombie) people in the world, and it's exceptionally lonely on the road. The two characters in The Road hardly come into contact with people, and they avoid the potential of contact as much as possible.