The local reactionary paper here had a big headline: "Dems Seize House!" As if it were a coup d'etat...in reality, the Democratic party "seized" nothing, except maybe the consciences of the people, who voted for themselves, in effect; for the people over the oligarchs; for small-d democracy after years of drifting towards a New Feudalism.
Whether the large-D Democrats will live up to the people's hopes is another matter...don't think your work is over just because the polls have closed!
In California, we voted in, among other things, a bill providing money for transportation "improvements." Too often, as we know, those efforts result in nothing more than adding lane-miles, which leads to more sprawl, more traffic, more congestion, and more calls for more lane-miles. As some forgotten traffic engineer said back in the '70s: "Curing congestion by adding more lanes is like curing obesity by buying bigger pants."
It's up to you to keep after your elected representatives to make sure than a large proportion of transportation improvements are of the sort that actually increase access and improve life on the ground.
The bulk of money should go to improving mass transit in and between cities, specifically rail. Nothing else can move so many people around, for so little energy spent, while taking up so little space. Indeed, subways take up almost no surface space at all, while having more capacity to move people (rather than cars) than freeways do. This frees up surface space for homes, shops, offices, factories, cafés, and sidewalks and bike lanes. Most of these uses pay property and often sales taxes, which freeways do not--a hidden benefit of subway building!
And it's again up to you to make sure that a lot of money goes to intelligent enhancements to bicycle infrastructure.
Bike lanes are nice, but don't really provide much; there's plenty of asphalt already with room for bikes. But bike racks everywhere; bicycle access to transit; pothole repair (the worst asphalt is always in the right lanes where busses, trucks, and bicyclists travel); traffic signal sensors that react to bicycles when a car isn't there; bike stations; subsidization of showers, lockers, and bike lockups at major employers (why not?--they get free road "improvements" to feed cagers into their parking lots); motorist education programs--the list is long.
As soon as your new representatives are settled into their offices, write them a note or an email, and let them know why you voted for them, and what you expect.
If they don't hear from you, they won't know what to do. So tell them!