Prior to starting my recent travels I lived within the DC metro system, which overall I will say is one of the better system in the United States. However the placement of some of the stations was less than ideal as the stations were clearly designed for cars and not the humans. Along with the design of the metro system is clearly moving people into and out of DC if you happen to not already be within DC.
I lived within about a half while walk of a station on one of the ends of the redline and some of my family lived on the other end. Using the metro from one end to the other end of the line was almost a two hour trip that by car would have only be around 30mins as the two ends of the line are not that far together, but they focus on just moving people into and out of DC.
The second thing that always stood out to me, was how dangerous the walk to my metro station was. It was down an road with a narrow sidewalk that had many bump and tree roots for tripping along with at night no street lights.
Even with the dangerous sidewalk, if you choose to walk you would reach the station to find the parking lot was placed in front of the station instead of behind the station meaning you now had to walk around a giant parking lot or risk walking through the parking lot with many cars that would be pulling in and out of paces not paying attention for humans around them.
After having lived in other countries with much better public transportations systems I am happy to see how far the DC area has come, but hope they continue to push for a human and not a car centric approach to public transportation.