On these street bridges, it would be safer simply because people be walking above the streets where there is no traffic. This may be expensive, but I think it would be worth it. This would make it faster and easier to walk to bus stops. I would also extend the Metro lines so that people who live in suburban areas could come into the city. I would also make more Metrobuses so that people would not have to wait more than 10 minutes for local buses.
Buses cause extreme air pollution and give off a lot of carbon dioxide.
A good way to decrease the air pollution caused by buses is to have them run by natural gas. This would decrease the carbon dioxide emission tremendously. If we could have bridges built above streets and improve the Metro system, that would be a start to helping clean up the mess that we have created. If we don't start now, who knows what our future holds. It is up to us to improve our environment by any means necessary.