Plenty of drivers complain about rush hour traffic, but some have more to complain about than others. Bangkok has the worst evening rush hour traffic in the world for a second consecutive year, according to a GPS manufacturer. Traffic expert Nick Cohn said that Thailand—and many other big cities at the top of the congestion ranking—have become victims of their own success. Growing economies and surging populations translate into more traffic and commuters. Mexico City, with the second worst evening rush hour traffic, has an extensive subway system but it doesn't extend out to where all the population growth is happening.