I like the idea. What spending programs would you look for these investments to help reduce or eliminate?
Our transportation department is designing the most inefficient and expensive auto only network in the world, so start there by eliminating parking minimums and dramatically encouraging non-auto travel. Start cutting immediately, and raise the gas tax/add a per mile driven charge to cars. No city has been able to eliminate traffic through road design, on the contrary the more and wider roads you build, the worse traffic gets. Just ask LA, Houston, Atlanta etc.
Raising the minimum wage and eliminating the part time working loopholes for employers will pull millions out poverty, reducing the need for food stamps and similar poverty programs. This has been proven over and over again to help.
Stop funding private schools, and move most of that funding into public schools like Finland. We will never have a great school system when money is being pumped into private schools and out of the areas most in need of great teachers and schools.
Move, shift money from incarceration into the the public health model of crime prevention where experts go and resolve the conflicts in the neighborhood conflict zones instead of just arresting people after the fact for violence. No, I'm not talking about de-funding police, just using experts to work on the source of the crime instead of cleaning up the mess.
Keep whittling down the cost of healthcare by creating a public healthcare system with honest limits to it's funding instead of allowing the stupid high prices of for profit healthcare.
Those are some off of the top of my head.