This seems like a non-starter. A quick conservation of energy check:
Human beings put out around 75W of energy when they're not excercising. Most of that is body heat. They also take around 10,000 steps a day, which translates to around 85 mins walking per day. Even in the scenario where you could capture 10% of that 75 human watts for those 85 minutes, that's only enough energy to run a 15W LED bulb for 42 minutes.
Harvesting energy from cars is also a non-starter. Any energy you harvest there is added as a load on the engine of the cars, which are all powered by fossil fuels. It's a really inefficient way to turn a car engine into an electric generator.