When voters in Tracy approved an annual "cap" on new housing construction last November, it was the first time since the late 1980s that a California municipality enacted this venerable โ yet controversial โ method of restricting growth. After grinding through 1,000 to 1,500 residential building permits annually for the last several years, the San Joaquin County commuter town will now have to restrict itself to 750 permits in any one year โ and an annual average of 600.