Massachusetts Windshield Mounting Laws (2026 Guide)

Massachusetts allows dashcam, GPS, and phone mounts on the windshield as long as they do not interfere with or impede the proper operation of the vehicle under MGL Chapter 90, Section 13, and do not obstruct the driver's view at the annual safety inspection under 540 CMR 4.04. MGL Chapter 90, Section 9D reaches something narrower: signs, posters, and stickers that obstruct the operator's vision, and window films and other nontransparent treatments. The state hands-free law (MGL c. 90, Section 13B) explicitly approves mounts on the windshield, dashboard, or center console for navigation use.

Massachusetts regulates what drivers can mount on or attach to their windshield through two primary statutes. MGL Chapter 90, Section 9D governs nontransparent materials and window obstructions. MGL Chapter 90, Section 13B addresses electronic device mounting under the state's hands-free driving law.

Together, these laws create a framework that allows mounted GPS units, phones, and toll transponders while prohibiting anything that blocks the driver's line of sight.

Massachusetts Windshield Obstruction Law (MGL c. 90, Section 9D)

Section 9D of Chapter 90 makes it unlawful to operate a motor vehicle on any public way with "any sign, poster, or sticker" on the front windshield, front side windows, rear side windows, or rear window if the item obstructs, impedes, or distorts the driver's vision.

The law also prohibits nontransparent materials, sunscreen material, window applications, reflective film, and nonreflective film that make the windshield or window glass nontransparent or obscured from either the interior or exterior of the vehicle.

Those two categories are the whole of Section 9D. A suction cup or adhesive mount holding a camera, phone, or GPS unit is neither a sign, poster, or sticker nor a film or window treatment, so Section 9D does not reach mounted hardware. Section 13 and the annual inspection rules do.

This statute applies to all motor vehicles driven on Massachusetts public roads and any way to which the public has the right of access.

What Section 9D Covers

The prohibition under Section 9D extends to the following areas of the vehicle:

• Front windshield
• Side windows immediately adjacent to the driver's seat and front passenger seat
• Side windows immediately behind the driver's seat and front passenger seat
• Rear window

The key legal standard is whether the item "obstructs, impedes, or distorts" the operator's vision. Items that do not interfere with the driver's view are not automatically prohibited.

Impeded Operation Law (MGL c. 90, Section 13)

MGL Chapter 90, Section 13 provides a broader rule. No person operating a motor vehicle shall permit anything on or in the vehicle, or on their person, that may "interfere with or impede the proper operation of the vehicle or any equipment by which the vehicle is operated or controlled."

This statute is the operative rule for windshield-mounted hardware, because such items do not fall under Section 9D's categories of signs, posters, or stickers and window films. Section 13 itself sets no penalty, so the Chapter 90 default in Section 20 applies: a fine of not more than $35 for a first offense, not less than $35 nor more than $75 for a second offense, and not less than $75 nor more than $150 for subsequent offenses committed during any 12-month period.

GPS and Phone Mounts

Massachusetts explicitly permits mounting GPS devices and phones on the windshield under the state's hands-free law (MGL c. 90, Section 13B), which took effect on February 23, 2020.

Section 13B states that a driver may "view a map generated by a navigation system or application on a mobile electronic device that is mounted on or affixed to a vehicle's windshield, dashboard or center console in a manner that does not impede the operation of the motor vehicle."

Approved Mounting Locations

The hands-free law specifies three approved locations for electronic device mounts:

• Windshield
• Dashboard
• Center console

The device must be mounted or affixed (not hand-held) and positioned so it does not impede vehicle operation. The safest placement is the lower corner of the windshield or on the dashboard, where it stays out of the driver's primary line of sight.

What You Can and Cannot Do With a Mounted Device

Even with a properly mounted device, the hands-free law limits what drivers can do:

• Allowed: View a navigation map on a mounted device
• Allowed: Use voice commands or hands-free mode to make calls
• Allowed: Touch the device once to activate hands-free mode
• Not allowed: Hold or support the device in your hand
• Not allowed: Read or send text messages, emails, or social media
• Not allowed: Browse the internet or watch video
• Not allowed: Use any app other than navigation while driving

Drivers under 18 face stricter rules. Under MGL c. 90, Section 8M, no person under 18 may hold in their hand or use a mobile telephone, hands-free mobile telephone, or mobile electronic device while operating a motor vehicle on any public way. This includes mounted devices.

Dashcam Mounting Rules

Massachusetts does not have a specific statute addressing dashcams. A windshield-mounted dashcam is not a sign, poster, or sticker and is not a window film, so Section 9D does not reach it. The rules that do apply are Section 13, which bars anything that interferes with or impedes the proper operation of the vehicle, and the annual safety inspection standard in 540 CMR 4.04, which requires rejection when an item attached to the windshield obstructs the operator's vision.

The safest placement for a dashcam is behind the rearview mirror, where it stays out of the driver's direct sightline. A dashcam mounted in the center of the windshield or in a location that blocks the driver's view could draw a citation under Section 13 and a rejection sticker at the annual inspection.

When selecting a dashcam mount, choose a compact unit that sits behind the mirror housing. Suction cup mounts placed elsewhere on the windshield are legal in Massachusetts, but placement matters for enforcement purposes.

Toll Transponders and E-ZPass

E-ZPass transponders and the newer E-ZPass stickers are permitted on Massachusetts windshields. These devices are small enough that they do not obstruct the driver's view under normal circumstances.

Massachusetts has been transitioning from traditional E-ZPass transponder boxes to RFID stickers that adhere directly to the inside of the windshield. The sticker format is smaller and creates even less potential for obstruction.

For vehicles with metallic-coated windshields that interfere with transponder signals, E-ZPass MA offers bumper-mounted transponders as an alternative.

Windshield Tinting Restrictions

Section 9D sets specific standards for window tinting on Massachusetts vehicles.

Front Windshield

• Nontransparent or sunscreen material is prohibited on the front windshield
• Transparent material is allowed on the uppermost 6 inches of the windshield
• The tint strip must not encroach on the driver's direct forward viewing area as defined by applicable Federal Motor Vehicle Safety Standards

Side and Rear Windows

• Side windows and rear windows must allow at least 35% visible light transmittance (VLT)
• Total visible light reflectance must not exceed 35%
• On the rear window, that 35% exemption is available only if the vehicle is equipped with two outside mirrors, one on each side, adjusted so the driver has a clear view of the highway behind the vehicle. Adding mirrors does not authorize film darker than 35% VLT anywhere on the vehicle

Tinting Standards Table

The Massachusetts Registry of Motor Vehicles (RMV) establishes the rules and regulations for measuring reflectance and transmittance. Annual vehicle inspections include a tint check, and windows that fail the 35% VLT standard will cause the vehicle to fail inspection.

Exemptions

Section 9D's exemption list is closed at items (1) through (8). The first two rows below are not statutory exemptions. They describe items that simply do not obstruct the operator's vision, so the Section 9D prohibition on signs, posters, and stickers never applies to them in the first place.

A marked cruiser without a K-9 team on board is not exempt under Section 9D(3). The exemption is written around K-9 units and requires the two outside mirrors as a condition.

Medical Exemptions

Massachusetts allows a tinted glass waiver for drivers with documented medical conditions that cause light sensitivity or photosensitivity. To apply:

1. Submit a written application to the RMV Medical Advisory Board
2. Include a written attestation from a physician licensed to practice in Massachusetts
3. The physician must confirm the applicant is light-sensitive or photosensitive
4. If approved, the RMV issues a compliance sticker to affix to the side window next to the driver

The medical exemption covers side windows and the rear window only. The front windshield cannot be tinted below the AS-1 line (top 6 inches) even with a medical waiver.

Penalties for Windshield Violations

Massachusetts assigns different penalties depending on the specific statute violated.

Section 9D Violations (Windshield Obstruction and Tinting)

Section 13 Violations (Impeded Operation)

Section 13 carries no penalty of its own, so the Chapter 90 default in Section 20 governs.

Section 13B Violations (Hands-Free Law)

A second or subsequent violation of Section 13B also requires the driver to complete a program approved by the RMV that encourages a change in driver behavior and attitude about distracted driving.

Vehicle Inspection Failure

Windshield obstructions and illegal tinting can cause a vehicle to fail its annual safety inspection under 540 CMR 4.04. Items attached to the windshield that obstruct the driver's vision will result in a rejection sticker. The vehicle owner has 60 days to correct the deficiency and pass a re-inspection.

The Hands-Free Law and Windshield Mounts

The Massachusetts hands-free law, signed by Governor Baker on November 25, 2019 and effective February 23, 2020, fundamentally changed how drivers interact with electronic devices.

Before the hands-free law, there was no explicit authorization for mounting devices on the windshield. The 2020 law created a clear legal framework by specifying that mounted navigation devices are permitted.

The law was passed as Acts of 2019, Chapter 122, which amended several sections of Chapter 90 including Sections 8M, 12A, 13, and 13B.

Emergency Exception

The hands-free law includes an affirmative defense for emergency use. Evidence that a mobile electronic device was used in response to an emergency is a valid defense against a Section 13B violation. However, this defense must be raised in court; it does not prevent a citation from being issued at the time of the stop.

Parked Vehicle Exception

A driver is not considered to be "operating" a motor vehicle under Section 13B if the vehicle is stationary and not located in a part of the public way intended for travel by a motor vehicle or bicycle. Drivers can use their phone normally when legally parked.

Recent Changes and Updates

No amendments to Section 9D or Section 13B were enacted during the 2025 legislative session. The core windshield obstruction and hands-free device laws remain as amended by the 2019 Acts, Chapter 122.

Massachusetts has been phasing in E-ZPass RFID stickers to replace traditional transponder boxes. New E-ZPass accounts receive the sticker format, which is smaller and adheres directly to the windshield glass. Existing transponder holders can continue using their current devices.

More Massachusetts Laws

• Massachusetts Recording Laws
• Massachusetts Lemon Law
• Massachusetts Hit and Run Laws