Sitting in the large house he built on a $95,000 plot of land in airy western Kabul and playing with his 5-year-old daughter, he is a member of a young Afghan generation whose eyes burn with modest aspiration for what would be by outside standards an ordinary life — access to electricity, schools for his son and daughter, rule of law, security.

“But I am quite afraid about the future at the moment,” he said. “If I got the chance, I would go now.”

Though all of Afghanistan’s major cities have grown and changed, the biggest differences, by far, can be seen in Kabul. Its population has exploded, now more than 5 million compared with 1.2 million in 2001, and its streets, planned for 30,000 cars, are clogged with 650,000, according to the mayor, Mohammad Yunus Nawandish. He is drawing up an expanded city plan that can accommodate up to 8 million residents.

The new urban elite makes up only a tiny slice of Afghan life — most of the newcomers to Kabul are impoverished migrants who now occupy terraces of rough mud houses that have splashed up onto the rocky hillsides surrounding the city.

And the norm is still grinding poverty for about 70 percent of Afghans, who live in the countryside, or about 25 million people by some estimates. Taken as a whole, life expectancy for Afghans is still just 48 years, and the average annual national income per capita is about $410. That makes the contrast with the markers of the middle class all the more striking: in Kabul, there are beauty parlors, a bowling alley, new television stations, access to health care (although Afghans must travel abroad for serious treatment), restaurants like Afghan Fried Chicken and children’s birthday parties hosted at nice hotels.