Complex sentence: The Miracle Mile District is one of the city's more densely populated areas, but is considerably more affluent than other high-density neighborhoods like Westlake and Koreatown, traffic congestion in the district is bad even by the standards of Los Angeles.
Split into simpler sentences: The Miracle Mile District is one of the city's more densely populated areas, but is considerably more affluent than other high-density neighborhoods like Westlake and Koreatown. As a result, traffic congestion in the district is bad even by the standards of Los Angeles.