Do you remember the time before Google Maps or GPS? You know, when you manually wrote down directions, got out a paper map, and hunted for the right street? You worked with a rough estimate of arrival time, and the only option to arrive earlier was to drive faster.
Map services today are based on a comprehensive knowledge of driving habits and typical traffic patterns, as well as information that affects those habits—maps of every street, road, and alleyway, as well as real-time data from traffic sensors, accidents/slow-downs, route diversions, and crowd-sourced input. The time savings from smarter route adjustments far exceed your ability to drive faster, and consequently, avoid those costly speeding tickets. Why does it work? Because it is comprehensive, organized, accurate, and accessible.