Missouri Windshield Mounting Laws (2026 Guide)
Missouri drivers who want to mount a GPS unit, smartphone, or dashcam on their windshield need to understand two areas of state law. The first is RSMo 307.173, which regulates what can be placed on or applied to a vehicle's windshield and windows. The second is the Siddens Bening Hands-Free Law (RSMo 304.822), which controls how drivers may interact with electronic devices while operating a vehicle.
Together, these statutes determine where you can place a mount, what devices you can attach, and how you are allowed to use them behind the wheel. This guide covers both laws in detail, along with penalties, exemptions, and practical tips for staying legal on Missouri roads.
Does Missouri Allow Windshield-Mounted Devices?
Missouri is one of the states that does not explicitly prohibit mounting a GPS, smartphone, or other device on the windshield. There is no standalone statute that bans suction cup mounts or similar accessories from being attached to the windshield glass.
However, this does not mean there are zero restrictions. Missouri law requires that nothing on the windshield interfere with the driver's ability to see the road clearly. The relevant statute is RSMo 307.173, which addresses sun-screening devices, tinting, and obstructions applied to vehicle glass.
Under this statute, labels, stickers, decalcomania, and informational signs are permitted on motor vehicles as long as they do not interfere with the driver's normal view of the road. The same principle applies to mounted devices. A GPS or phone mount is legal in Missouri, but it must be positioned so it does not block the driver's line of sight.
RSMo 307.173: Windshield Obstruction Rules
The primary statute governing windshield obstructions in Missouri is Section 307.173 of the Revised Statutes of Missouri. While this law focuses mainly on window tinting and sun-screening devices, it establishes the legal standard for anything placed on vehicle glass.
Key Provisions
The statute sets specific requirements for window tinting and applied materials:
- Front side windows must allow at least 35% light transmission (plus or minus 3%)
- Luminous reflectance on front side windows must be 35% or less (plus or minus 3%)
- Non-reflective tint is permitted on the windshield only above the manufacturer's AS-1 line (typically the top 5 to 6 inches)
- No material may be applied to the windshield below the AS-1 line that would obstruct the driver's view
- Labels, stickers, and informational signs are allowed as long as they do not interfere with the driver's normal view of the road
How This Applies to Mounts
Although RSMo 307.173 does not specifically mention GPS mounts or phone holders, the general obstruction standard applies. Any device or accessory attached to the windshield must not interfere with the driver's normal view of the road. A mount placed in the center of the windshield directly in the driver's line of sight could be considered a violation, while a mount positioned in the lower corner or near the edge of the windshield is generally acceptable.
Penalties for Windshield Violations
A violation of RSMo 307.173 is a Class C misdemeanor under Missouri law. Class C misdemeanors in Missouri can carry a fine of up to $750. While enforcement of this statute for device mounts is uncommon, a poorly placed mount that clearly obstructs the driver's view could result in a traffic stop and citation.
The Siddens Bening Hands-Free Law (RSMo 304.822)
The more impactful law for Missouri drivers who mount devices on their windshield is the Siddens Bening Hands-Free Law, codified in RSMo 304.822. Governor Mike Parson signed this law on July 7, 2023. A warning-only period ran from August 28, 2023, through December 31, 2024. Full enforcement with fines began on January 1, 2025.
What the Law Prohibits
Under RSMo 304.822, no driver may:
- Physically hold or support an electronic communication device with any part of their body while operating a motor vehicle
- Write, send, or read any text-based communication on an electronic communication device while driving
- Make video calls or use FaceTime
- Manually type or dial a phone number
- Browse the internet, watch videos, or play games
- Take photos or record videos by hand
The law applies on any highway or property open to the public for vehicular traffic in Missouri.
What the Law Allows
Drivers may still use electronic devices in the following ways:
- Voice commands: Making calls, sending texts, or getting directions through voice-activated features
- Single touch or swipe: Answering or ending a call, starting navigation, or changing music with one quick tap or swipe on a mounted device
- Hands-free calling: Using Bluetooth, speakerphone, or the vehicle's built-in communication system
- Mounted navigation: Viewing a map or GPS directions on a device that is properly mounted in the vehicle
- Audio controls: Accessing music or podcasts through a single touch on a mounted device
The critical requirement is that the device must be mounted, not held, and interaction must be limited to a single touch or swipe that does not divert attention from driving.
Definition of "Electronic Communication Device"
Under the statute, an "electronic communication device" is defined as any portable device used to initiate, receive, store, or view communication, information, images, or data electronically. This includes:
- Cell phones and smartphones
- Tablets and portable computers
- GPS navigation units
- Portable media players
- Smartwatches with communication capabilities
- Any similar portable electronic device
Definition of "Hands-Free Feature"
The law defines a "voice-operated or hands-free feature or function" as any feature, whether internally installed or externally attached to the device, that allows a person to use an electronic communication device without the use of either hand. The only manual interaction allowed is a single touch or single swipe to activate, deactivate, or initiate the feature.
Penalties for Hands-Free Law Violations
The Siddens Bening Hands-Free Law carries escalating penalties based on the number of offenses and the consequences of the violation.
Standard Fines
| Offense | Timeframe | Maximum Fine |
|---|---|---|
| First violation | No prior conviction in 24 months | $150 |
| Second violation | One prior conviction within 24 months | $250 |
| Third or subsequent violation | Two or more prior convictions within 24 months | $500 |
Enhanced Penalties in Special Zones
Violations that occur in certain designated areas carry enhanced fines of up to $500 regardless of whether it is a first offense:
- Work zones: When workers are present
- School zones: Areas designated and marked to alert drivers to the presence of a school zone
Penalties When Violations Cause Harm
The consequences increase significantly when a hands-free violation leads to an accident:
| Outcome | Charge | Potential Penalty |
|---|---|---|
| Property damage exceeding $5,000 | Class D misdemeanor | Fine up to $500 |
| Serious physical injury to another person | Class B misdemeanor | Up to 6 months in jail and up to $1,000 fine |
| Death of another person | Class D felony | Up to 7 years in prison and up to $10,000 fine |
Points on Your License
A standard hands-free violation is classified as an infraction under Missouri law. The Missouri Department of Revenue has indicated that no points are assessed on a driver's license for a basic infraction under this statute. However, if the violation escalates to a misdemeanor or felony due to an accident causing injury or death, additional consequences including points and license suspension may apply.
Exemptions to the Hands-Free Law
RSMo 304.822 includes several exemptions for specific situations and categories of drivers.
Emergency Situations
The law does not apply to a driver who is:
- Reporting an emergency to law enforcement, a health care provider, a fire department, or another emergency services agency
- Using the device to receive emergency alerts or notifications
Emergency Personnel
Law enforcement officers and operators of emergency vehicles (as defined in RSMo 304.022) are exempt when they are using the device in the performance of their official duties and actively operating an emergency vehicle.
Commercial Motor Vehicle Operators
Operators of commercial motor vehicles have specific exemptions:
- They may use a voice-operated or hands-free feature as long as they remain seated and restrained by a seat belt
- They may read messages displayed on a permanently installed communication device designed for a commercial motor vehicle, provided the screen does not exceed 10 inches in height
Parked or Stopped Vehicles
The law does not apply to a driver whose vehicle is lawfully parked or stopped and not in active traffic. If you pull over to the side of the road or are parked in a parking lot, you may use your device normally.
Best Practices for Windshield Mounting in Missouri
While Missouri law permits windshield mounts, following these guidelines will help you stay within the law and avoid unnecessary attention from law enforcement.
Recommended Mount Placement
- Lower right corner: Mounting near the lower passenger-side corner of the windshield keeps the device accessible while minimizing obstruction of the driver's view
- Dashboard mount: Using a dashboard-mounted holder avoids windshield placement entirely and eliminates any concern about windshield obstruction
- Vent or CD slot mount: Clip-on mounts that attach to air vents or the CD slot keep the device at eye level without touching the windshield
- Avoid the center: Never mount a device directly in the center of the windshield in the driver's primary line of sight
Device Setup Tips
- Program your destination before you start driving
- Enable voice commands for navigation, calls, and messages
- Set your phone to "Do Not Disturb" mode to reduce the temptation to interact with notifications
- Adjust the screen brightness so it does not cause glare or distraction at night
- Secure the device firmly so it does not fall or shift while driving
What to Avoid
- Holding your phone against the steering wheel, even briefly
- Resting your phone on your lap or thigh while driving
- Using two hands to interact with a mounted device
- Typing an address into GPS while the vehicle is in motion
- Watching any video content while driving, even on a mounted screen
Missouri Windshield Tint Rules
Understanding Missouri's windshield tint laws is also important for drivers who mount devices, because tint placement and mount placement both affect visibility.
Under RSMo 307.173:
- Non-reflective tint is allowed only above the AS-1 line on the windshield (the top 5 to 6 inches)
- No tint may be applied below the AS-1 line on the front windshield
- Front side windows must allow at least 35% visible light transmission
- Rear side windows and rear windshield may have any level of tint
- Medical exemptions are available through the Missouri Department of Public Safety for individuals whose physicians prescribe darker tinting due to a serious medical condition
A medical exemption requires a sticker affixed to the lower left corner of the windshield and a decal on the rear glass or bumper.
How Missouri Compares to Neighboring States
Missouri's approach to windshield mounts is relatively permissive compared to some neighboring states. Here is a quick comparison:
| State | Windshield Mount Allowed? | Hands-Free Law? |
|---|---|---|
| Missouri | Yes, if it does not obstruct the view | Yes, fully enforced since January 1, 2025 |
| Kansas | Restrictions on windshield placement | Yes |
| Illinois | Limited to specific windshield areas | Yes |
| Iowa | Yes, with obstruction restrictions | Partial restrictions |
| Arkansas | Yes, with obstruction restrictions | Partial restrictions |
| Oklahoma | Yes, with obstruction restrictions | Partial restrictions |
Drivers who frequently cross state lines should check the specific windshield mounting rules in each state they visit, as laws vary significantly.
More Missouri Laws
If you are researching Missouri traffic and vehicle laws, these related guides may help:
Sources and References
- RSMo 307.173 - Specifications for sun-screening device applied to windshield or windows(revisor.mo.gov).gov
- RSMo 304.822 - Siddens Bening Hands-Free Law(revisor.mo.gov).gov
- RSMo 304.820 - Electronic communication device definitions(revisor.mo.gov).gov
- RSMo 304.022 - Emergency vehicle definitions(revisor.mo.gov).gov
- Phone's Down, It's the Law - Missouri Department of Transportation(savemolives.com).gov
- Missouri Revised Statutes Chapter 307 - Vehicle Equipment Regulations(law.justia.com)
- RSMo 304.822 Full Text - Justia(law.justia.com)