A new law signed by Governor Davis today will make it easier for police officers to impound cars when the driver is illegally street racing. Reckless drivers and so-called sideshow street racers could lose their cars for up to 30 days. Current law lets officers impound vehicles involved in speed contests. The new legislation expands that law to include vehicles involved in reckless driving or speeding. It goes into effect January First. The legislation was prompted by a February accident that killed a 22-year-old Oakland woman.