“Sometimes when people make fun of me, I wish I had been killed by the bomb, because it’s a lifetime torture,” he said, perched on a cushion in his home as he prepared for a day of driving.

Mr. Haidari said he had been deeply hurt when no one from the army called to check on him after he was wounded. Since then, he said, he has received a small government stipend, which helped cover the costs of building his wheelchair-accessible home a year ago, but he still feels abandoned.

“I served the Afghan Army and my country, but now I’m no one to them because I can’t do anything for them,” he said. “They don’t care that I lost my legs because of the war.”

Even so, he is determined to persevere. When he saw a legless army veteran in Kabul using his hands to drive a retrofitted car, it inspired him to design a similar device.

He said he took his hand-drawn plans to a mechanic in his hometown, Bamian, but the man refused to help, saying the task was impossible. But Mr. Haidari hectored him, and he relented.

The two men rigged a contraption that lets Mr. Haidari guide the steering wheel with his intact right hand and the accelerator with his left thumb, which controls a lever. He also uses the thumb to apply the brakes, by pushing a blue-taped knob. The retrofit cost him 5,500 afghanis, or about $70.