" I looked for places in the existing budget where revenues generated were higher than expected. School-zone cameras was one such place,” Bagshaw said Friday. School-area projects would still see more money under her plan than they were allocated in Durkan’s budget, the council member said.
The problem here is that, generally, the non-capitalized revenues generated need to be spent within the fiscal year, or some agreed upon time frame (this is where City economists work their "magic"), and cannot be rolled over into future years if they are not in the budget. That is how City accounting works. You can't just say "let's hold onto that, we'll spend in two years from now." Everyone flips out and tries to find ways to spend the money ASAP, even if it is on bad ideas, as this money can't be rolled over. If you don't spend your budget (especially if you under-spend by greater than 10%), then you get the spotlight put on you, and the Council can punish you by squeezing department heads to slash budgets to meet your under-spent year... now you have less money for next year, a year that you actually may need more budget, as projects, delays, etc., don't always follow the fiscal year. This makes Directors/Managers, etc. nervous, as they see the Council wanting to take their budget away, so they react by finding projects to spend the money on, so that they can have the same budget next year and aren't "penalized" for saving money (i.e. under-spending).
It's actually funny, as it's almost worse to under-spend than over-spend. Over-spending is an "indication" that you need more resources, and are a group than can be looked at to spend money when the above-noted problem arises in other groups that fall under a similar budgetary umbrella (so that budget can be transferred between them, which isn't always the case). These groups can typically ask for, and possibly receive, more budget in the future, as they are seen as productive. Under-spending groups/projects/etc. are seen as liabilities, as now they not only have to find places to spend their budget, now they are at risk for budget reduction in the future. They have double the problems compared to the over-spenders.
The above under-spending case results in the Council having Dept heads look at the numbers, and saying "can you spend this?". The Dept heads crunch the numbers and know that they don't have the ability to responsibility (or less-than-responsibly) spend this amount of spillover budget, don't want to get their hands slapped, so they answer honestly, and the Council looks for "shovel ready", or "______ ready" projects that this money can be spent on... these are likely to be projects that will give them the most political bang for their buck.
This is the gist of how it works.