Suction cup windshield mounts for smartphones and GPS units are popular choices among many, but they aren't legal everywhere in the United States. In other states, they may be legal, but must be positioned and used in specific ways. While Minnesota and Wisconsin aren't among the 20 states that straight-up outlaw suction cup windshield mounts, there are some specific rules you do need to know about.

ProClip USA, a device holding manufacturer, broke down the laws of each state about usage of these device holders. They explain that while states like North Dakota, Illinois, Nebraska, Montana, and several others, suction cup windshield mounts are illegal. You might want to keep that in mind on your next road trip through these (see full list) states. When it comes to our two great states, usage of these devices is legal, but how you use them and what devices are being held by these windshield mounts is regulated.

Wisconsin

Rules on usage of suction cup windshield mounts in Wisconsin is pretty straightforward. According to ProClip, they can be used to hold either smartphones or GPS devices, as long as they aren't mounted in the line of sight of the driver for non-commercial and non-emergency vehicles.

Looking further at the Wisconsin Statute [346.88 (3)(a)-(c)], the law does offer further detail, specifying that (b) "No person shall drive any motor vehicle upon a highway with any object so placed or suspended in or upon the vehicle so as to obstruct the driver's clear view through the front windshield." and (c) "No person shall drive any motor vehicle upon a highway so loaded or with any object so placed or suspended in or upon the vehicle so as to obstruct the driver's clear vision through the rear window unless such vehicle is equipped with an outside rear view mirror meeting the requirements of s. 347.40."

Minnesota

The rules are a little more nuanced for Minnesota. ProClip explains that suction cup mounts are allowed to hold only GPS devices, and not smartphones, as long as they are mounted in the very bottom-most part of the windshield. The Minnesota statute doesn't give specific measurements for what is legally the "bottom-most part" of the windshield, but the goal is to keep the normal field of view for the driver clear.

I know you're probably thinking what I am - "Wait, what if I use my phone as a GPS unit?" According to ProClip's information, being that smartphones are also capable of being entertainment and communication devices that could distract a driver, they're classified in a different category, and thus not legal in windshield mounts in Minnesota.

You can see the full statute (Minnesota Statute 169.71) here, which discusses not only windshield mounts, but also other rules about vehicles windows and specifically the windshield.

Regardless of whether you're in Minnesota or Wisconsin, vent-based or cup holder-based device holders offer additional alternatives that completely avoid obstructing any of the windshield. The downside to those options for holding your navigation devices is that they could pull drivers' eyes further away from the road than windshield-based options. There are pros and cons to each option, so be informed and most of all, keep in mind that while you're driving, keeping yourself from being distracted.