The Ultimate Bike City

Okay, stick with me here, the problem with vehicles (of all sorts) is they require an enormous amount of energy to "go". A modern minivan has a 200 horsepower engine, which is equivalent to 149 kilowatts, or the electrical power consumption of 118 US residential consumers. IS THAT NOT LUDICROUS???????

That aside, the problem is putting that enormous amount of energy INTO the vehicle. Today, gasoline is popular, because it has an astonishing amount of energy locked up in its molecules, and because it's literally just lying around in holes in the ground. Obviously these holes aren't likely to be infinite (AND FOSSIL FUELS ARE NOT RENEWABLE BECAUSE OF FUNDAMENTAL CHANGES IN BIOLOGY) so alternatives have been sought after for some time.

Ford's 1941 Soy Plastic/Soy Fuel Car

Oh, oops, actually no, the first successful car, the Model T, was designed to run on perfectly renewable hemp ethanol, so we've had the solution the whole time, but we forgot. Furthermore, Ford made a bioplastic car in 1941 that also ran on soy alcohol. Nobody cared.

Anyway, my new idea was, what if the energy for the vehicle was stored not inside the actual vehicle, but inherently in the infrastructure? I call this idea the gravity battery.

The city I'm imagining will be a 1/2 mile circle, encompassing 125 acres of space. A central tower in the middle of the city will contain several constantly operational hydraulic elevators. Upon entering the town, you will find your way to an elevator, get as much height as you can, then roll to your destination. All slopes will, eventually, lead to the central tower, and there will be many smaller towers around the routes that you can stop and get off on.

With this design, assuming the central tower has a top height of 120 feet which is about 10 standard city stories, all of the pathways will be a roughly 4.5% grade or greater, which is a comfortable downhill cruise, but nothing you'll lose control on.

Furthermore, for those in need of a more comfortable experience, light-weight electric assisted soapbox cars could be utilized. Soapbox racing has come a long way, and some of the modern speed attempts are just as technologically advanced as modern cars.

My new commuter car - instructables.com

This is not an example of tech, but is nevertheless absolutely gorgeous.  With a small electric assist added should you get stuck on flatground, this car would be perfectly capable of getting around town at a reasonable speed.

I don't see a problem with this plan, but "I'm not a scientist".