One-way Streets w/Bike Lanes & Perpendicular Parking
By turning many streets, particularly in more residential neighborhoods, into one-way streets with a single lane of traffic, we could create designated bike lanes and enable perpendicular parking on one side of the street, creating 25%-50% or more parking spaces per block. You might even have space to 'green up' streets with mini parks and seating areas.
Most blocks have absolutely no need for two-way traffic. The lanes are empty 98% of the time over 24 hours and dedicating that much space to traffic is a waste of resources. The downside is you might have to drive a block out of your way to get home but that beats circling the block for 30 minutes looking for a parking spot.
One-way streets can also calm traffic and potentially allow traffic circles at key intersections without additional land dedicated to asphalt. Traffic circles have many benefits to a community including eliminating four-way stops at every intersection - which are terrible for the environment by destroying gas mileage and increasing the efficiency of transit.