In my sustainability city I would have city buses just like the ones we have now however they would be completely electric to reduce the amount of fossil fuels that we burn using city buses. Next I would have a place where you could rent bicycles, scooters, skate bordes, etc kinda like a library except for things like bikes so that people would have no excuse as to why they easily just bike to where they need to go. How ever I understand that some people have long commutes so I would also set up something like uber except the only cars allowed in this program are electric ones. Finally I would somehow offer every citizen a new electric car in exchange for their gas cars to reduce then cities carbon foot print as much as I could.

I agree with you. What I would do is charge a ton of money to park in the downtown area, and lower bus costs significantly. Now, I am assuming my city is along the north western European coats because I want to live there, so there is always some sun and calm breeze. So thus, I would put numerous wind farms around the city, followed by solar power batteries and panels on top of most buildings downtown, which would presumably be elevated slightly above the cloud. Of course, I won't eliminate fossil fuels entirely at once. It would be a long and slow process, and there will be backup.

This seems like an excellent idea and one that I am fully behind. I do have some questions for your sustainable city though. I was thinking more along the lines of long distance, such as what if a family wanted to head to another state or country to visit their relatives, how would they get the transportation. I would also have buses in local areas that were electric and they would run frequently as to get people on time to work. Self driving cars would also maximize efficiency. I don't have a solution for the long term distance problem but if anyone does feel free to comment.

I agree with your ideas. i think the bus idea is great, It combines carpooling and electric vehicles, which are two major things people are doing to reduce the use of fossil fuels in todays society. Exchanging cars might be a difficult taste due to the amount of money used and then what would happen to the old cars? i would suggest finding a way to change gas powered cars into electric cars; this would lower the cost and reduce the waste.

I agree with you! The easiest way to reduce carbon emissions is to use a “vehicle” that has no need for an engine or battery at all. Many people use their lack of a bicycle as an excuse to drive cars. This “bicycle library,” although very idealistic, would be the perfect idea for people who can’t afford a scooter, skateboard, or bike. Another, much simpler solution, is just to walk. This might be inconvenient for some, but it would also encourage people to exercise. A more convenient solution now could turn into a large problem around the globe later. 
And for those in a rush, electric cars should be the only option. And an increasing number of electric cars are just as essential as the reduction of gas guzzling cars. According to the U.S Department of Energy, electric cars can convert 59%–62% of the electrical energy from the grid to power at the wheels, while gasoline powered cars only convert about 17%–21% of the energy. The article also states that electric cars  accelerate more quickly, drive more smoothly, and use a renewable resource: electricity. The only downsi de, the higher cost, can also be solved if electric cars can be exchanged for gasoline cars, like you said in your paragraph. This is idealistic, though.
In my ideal sustainable city, only electric cars and buses would be used, and bicycles would be accessible to everyone. Travel by plane would also be limited in order to reduce the city’s overall carbon footprint. Rooftop gardens would be planted to reduce the amount of carbon dioxide emitted, and the city would be solar, wind, and water powered.
Source:
https://www.fueleconomy.gov/feg/evtech.shtml