In most states, you need side mirrors on both the right and left of the vehicle if you can't see out the back. Alaska appears to have this. They also have restrictions on the tint level of both front and back windows. There are exceptions for medical conditions and for some types of vehicles (motor homes, limos, "multi purpose vehicles", etc).
Here's the relevant laws for Alaska:
Alaskan Admin Code: 13 AAC 04.223. Tinted vehicle windows
13 AAC 04.223. Tinted vehicle windows
(a) A person may not drive a motor vehicle on a highway, public road, street, or parking lot with mirrored tinting material on any window of the vehicle. Except as provided in this section, a person may not drive a motor vehicle on a highway, public road, street or parking lot with aftermarket tinting material or aftermarket striping material on any window of the vehicle.
(b) Aftermarket tinting of vehicle windows is allowed as follows:
(1) the front windshield may have a strip of tinting material applied to the top edge, known in the industry as an "eyebrow," which does not extend downward more than five inches from the top of the glass;
(2) the driver and front passenger side windows may have tinting material that permits at least 70 percent light transmittance;
(3) the rear door windows, quarter glasses, and back glasses may have tinting material that permits at least 40 percent light transmittance;
(4) limousines and passenger buses used to transport persons for hire, motor homes, and vehicles identified by the vehicle manufacturer as multipurpose may have tinting material that complies with Standard No. 205, Glazing Materials, in 49 C.F.R. 571.205 (1992).
(c) The windows of a vehicle may have tinting material that permits less light transmittance than that specified in (b) of this section if
(1) a driver or a passenger who frequently travels in the vehicle is required for medical reasons to be shielded from the direct rays of the sun;
(2) the medical reasons are certified annually by a physician licensed to practice in this state; and
(3) the certification is carried in the vehicle.
(d) Tinting materials must be green, gray, bronze, or neutral smoke in color, or a sun reflective auto film.
(e) Light transmittance must be measured by using a light transmittance measuring device with an allowance for manufacturing variances of plus or minus three percent. The accuracy of the device must be certified by the manufacturer.
(f) In this section, "light transmittance" means the ratio, expressed as a percentage, of the amount of total light that is allowed to pass through a window, including glazing, to the amount of total light falling on the window.
(g) All vehicles must comply with this section by July 1, 1994.
(h) A tinted rear window on a motor vehicle is exempt from regulations relating to the tinting or luminous transmittance materials used in motor vehicle windows, if the vehicle's owner has proof that the rear window tinting was installed before July 1, 1994, and the vehicle is equipped with driver-side and passenger-side rearview mirrors.
