Nice so you don't have to floor it to make a yellow or Kickstart your air-cooled motorcycle when a long red turns green.
The timing is off by 3 seconds to stop people from going just before it turns green. So people go 4 seconds early.
The US usually leaves towns legally distinct as they blend together. We tend to call the whole area by the city name, with only locals using the actual town names. Microsoft, for example, is based in Redmond, not Seattle. Google is based in Mountain View, Facebook is in Menlo Park, Apple is in Cupertino, and Intel/NVidia are in Santa Clara, but those are all San Fransisco to non-residents.
If you go by Metro Statistical Area (MSA), there are two cities over 10mil, 9 between 5-10mil, and 45 between 1-5mil.