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Since July 1, 2026 (House File 766), Iowa Code 321.438(2) bars operating on the highway a motor vehicle with a front windshield below 70% light transmittance, or a side window to the immediate left or right of the driver, or a sidewing forward of the driver, below 50%. No tolerance is stated. Rear side windows and the rear window have no percentage and must only permit clear vision (321.438(1)).
Source: Iowa Code § 321.438 (as amended by 2026 Iowa Acts ch. 1100, H.F. 766); Iowa Code § 321.438 (Iowa Code 2026 print, before H.F. 766); H.F. 766 enrolled bill and history (effective July 1, 2026); Iowa Admin. Code 761-450.5 (front windshields, windows or sidewings); Iowa Admin. Code 761-450.7(3) as in effect April 13, 2022 (pre-2012 dark window exemptions); Iowa Code § 805.8A(3) (scheduled fine). Summary last checked against these sources on September 28, 2026.
| Window | Rule |
|---|---|
| Windshield | A person may not operate on the highway a motor vehicle with a front windshield that has less than 70% light transmittance (321.438(2)(a)(1)). The statute states no top-strip allowance and no measuring tolerance. |
| Front side windows | A side window to the immediate right or left of the driver, and a sidewing forward of and to the left or right of the driver, may not have less than 50% light transmittance (321.438(2)(a)(2), as amended by H.F. 766, effective July 1, 2026). No tolerance is stated. The Iowa DOT rule print read on September 28, 2026 (IAC 4/16/25) still defines "excessively dark or reflective" as below 70 percent for the windshield, front side window and front sidewing (Iowa Admin. Code 761-450.5(1)), wording the amended statute no longer uses. |
| Rear side windows | No percentage. Section 321.438(2) covers only the windshield and the windows and sidewings beside and ahead of the driver. The general rule still applies: no driving a motor vehicle whose side or rear windows do not permit clear vision (321.438(1)). |
| Rear window | No percentage. The rear window is subject only to the clear-vision requirement of 321.438(1). |
| Reflectance | H.F. 766 struck the words "excessively dark or reflective" from 321.438(2). The amended subsection sets only light-transmittance figures and states no reflectance limit. The DOT rule still uses that phrase and defines it by the 70 percent transmittance standard (Iowa Admin. Code 761-450.5(1)). |
VLT (visible light transmission) is the percentage of visible light that passes through a window or film; a higher number means lighter tint. Most state limits are measured on the finished window (glass and film together). Where a rule is stated for the film itself, the table says so. Some states also limit reflectance, the share of light bounced back off the surface (a mirror-like look).
Section 321.438(2) applies to any motor vehicle operated on the highway and draws no distinction between cars, SUVs, pickups or multipurpose vehicles. It does not apply to a person operating a vehicle owned or leased by a federal, state or local law enforcement agency as part of the person's official duties (321.438(2)(b)). The 50 percent front-side figure took effect July 1, 2026. The Iowa Code 2026 print of 321.438 predates H.F. 766 and still shows the old wording.
Neither 321.438 nor H.F. 766 contains a medical exemption. Under Iowa Admin. Code 761-450.5(2), vehicles operating with a dark window exemption issued before July 4, 2012 are subject to rule 761-450.7(3) as in effect April 13, 2022. That text granted no exemptions from July 4, 2012. It let a vehicle fitted before that date with a front windshield, front side window or front sidewing between 35 and 70 percent keep that glass while it carries the passenger or operator who is the subject of Form 432020. That form is a statement of medical need signed by the person's physician before July 4, 2012, and it must be carried in the vehicle. The exemption expires when the vehicle no longer carries that person and may not be renewed; the vehicle must then be brought into conformance within 60 days. The amended statute sets the 70 and 50 percent figures itself, has only the law-enforcement exception and no longer directs the DOT to set the standard by rule, so the text read does not settle whether this grandfathered exemption still applies.
A violation of section 321.438 is an equipment violation with a scheduled fine of $70 (Iowa Code 805.8A(3)(ai), Iowa Code 2026 print).
From July 1, 2026, the front windshield must have at least 70% light transmittance and the side windows and sidewings to the immediate left or right of the driver at least 50% (Iowa Code 321.438(2)(a), as amended by H.F. 766). The statute states no tolerance and sets no percentage for the rear side windows or rear window.
Yes. House File 766, approved May 15, 2026 (2026 Iowa Acts ch. 1100), took effect July 1, 2026. It replaced the "excessively dark or reflective" wording in 321.438(2) with figures in the statute: 70% for the front windshield and 50% for the front side windows and sidewings. Before that, the DOT rule set 70 percent for all three (Iowa Admin. Code 761-450.5(1)), and the rule text read on September 28, 2026 still says 70 percent.
The statute sets no percentage for the rear side windows or the rear window, for cars or SUVs. Section 321.438(1) still bars driving a motor vehicle whose side or rear windows do not permit clear vision.
The amended 321.438(2) does not mention reflectance: H.F. 766 struck the words "excessively dark or reflective" and set light-transmittance figures instead. The DOT rule still uses that phrase, defined by the 70 percent transmittance standard (Iowa Admin. Code 761-450.5(1)).
Not in the statute, and the DOT rule text in effect April 13, 2022 said no exemption would be granted from July 4, 2012. That rule text lets a vehicle with a dark window exemption issued before that date keep front glass of at least 35 percent while it carries the person named on Form 432020, which must be kept in the vehicle (Iowa Admin. Code 761-450.5(2)). The amended statute contains no such exception, so the text read does not settle whether it still applies.
Yes. Section 321.438(2) does not apply to a person operating a vehicle owned or leased by a federal, state or local law enforcement agency as part of the person's official duties (321.438(2)(b)).
The scheduled fine for a violation of section 321.438 is $70 (Iowa Code 805.8A(3)(ai), Iowa Code 2026 print).
Running a tint shop in Iowa? See shop software for Iowa.
This page summarizes Iowa statute and regulation text for general information and is not legal advice. It covers passenger vehicles with aftermarket film (film added after the vehicle left the factory) and includes SUV, van and truck rules where the state sets different ones. Some vehicle types, such as limousines, buses, commercial and law-enforcement vehicles, and factory glass are treated differently in some states, and whether a vehicle registered in another state is covered depends on the state; see “Who this covers” above. Federal glazing rules (FMVSS 205, 49 CFR 571.205) apply separately from state law, and 49 U.S.C. 30122 bars manufacturers, distributors, dealers, rental companies and motor vehicle repair businesses from knowingly making inoperative any part of a device or element of design installed to comply with a federal motor vehicle safety standard, so installers should check both. Laws change and enforcement varies; confirm current requirements with the state before tinting. Before tinting, ask the installer to measure your glass and confirm the finished window will meet the limit; afterward, ask for a reading on a light-transmission meter and keep it.