Many California cities have adapted to growth by implementing very effective traffic calming tactics. Through engineering and signage, streets can be designed so that drivers can't speed, making streets safer for pedestrians, bicyclists and vehicles. Below are some examples from cities that have these measures in place, like Berkeley, Hayward and Culver City.
Cars must slow down for speed cushions, but they are not as dramatic as speed bumps.
At 4-way intersections, small roundabouts can slow cars as they manuever around the center island.
These wide and relatively shallow speed humps or cushions can slow traffic and keep drivers from gaining too much speed on residential streets
Intersections like this with "bulb out" corners slow traffic and shorten the length of cross walks, making them safer. Crosswalks are also boldly painted with wide white stripes, and the yellow poles draw extra attention for drivers.
Small roundabouts like these at 4-way intersections force drivers to slow down to maneuver around the center island.
Just having clearly marked lanes on residential streets can vastly improve speed. When there are no lanes, cars have the full width of the street, making it easier to drive fast.