You'd have to check CA vehicle codes. I know in Washington State the bumper laws are pretty strict.
(a) Be at least four and one-half inches in vertical height.
(b) Be centered on the vehicle's centerline.
(c) Extend no less than the width of the respective wheel track distances.
(d) Be attached to the vehicle in a manner equivalent to the original manufacturer's installation.
(e) Be horizontal load bearing and attach to the vehicle frame to effectively transfer energy when impacted.
(f) Be mounted at a maximum height based on the original gross vehicle weight rating (GVWR) of the vehicle, measured from a level surface to the highest point on the bottom of the bumper. For vehicles exempted from the bumper requirement for the reasons stated above, a maximum frame elevation measurement must be made to the bottom of the frame rail. Maximum heights are as follows:
Passenger Vehicles: Front: 22 Inches Rear:22 Inches
4,500 lbs. and under GVWR: Front: 24 Inches Rear: 26 Inches
4,501 lbs. to 7,500 lbs. GVWR: Front: 27 Inches Rear: 29 Inches
7,501 lbs. and over GVWR: Front: 28 Inches Rear: 30 Inches