The short answer is no, it’s unsafe to drive with a cracked windshield. There are numerous reasons why, but some common issues that arise when driving with one include poor visibility, a weakened cabin structure, its tendency to spread, and lack of protection from the elements.
But while it is generally unsafe to drive with a cracked windshield, whether you could still safely drive your car depends heavily on the size of the crack, where it happens to be, and whether it is spreading. A small star-shaped rock impact chip isn’t a problem unless it turns into a growing crack. The windshield, unlike the rest of the glass, is two layers of glass with a clear, sticky rubbery layer between them to prevent the windshield from filling the vehicle with shards if something hits it and breaks it. So if the crack is small and only on the outside layer of glass, it isn’t as serious as a crack that has breached both layers.
As for the structure of the cabin, that’s another variable that varies from vehicle to vehicle. The potential problem is that you can’t be sure if it’s a problem for your vehicle or not.
Poor Visibility
A cracked windshield can affect your view of the road, especially if it’s in front of the steering wheel. Even ones that aren’t can still be distracting, even for experienced drivers. More so than the lack of clear vision, cracked glasses reflect sunlight which could momentarily deprive you of your sight.
In addition to cracks, there is also sand-pitted windshield (uniformly pockmarked by sand over a long period of time) that can cause serious visibility problems if the sunlight is hitting the glass at the wrong angle. Even if the windshield isn’t cracked, a sand-pitted windshield should be replaced.
Weakened Structural Integrity
The windshield is an important part of the cabin’s overall integrity (more on some cars than others), especially during cases of front-end collisions.
Cracks on the glass may compromise its overall integrity, making crashes more fatal due to potential shards of glass injuring the passengers. Note, however, that windshields are specifically designed to minimize this risk. Side and rear glass break into tiny cubes for the same reason, but the windshield must resist impact of hard objects, birds, etc. at road speed, so it’s a different kind of glass. Still, a perfectly intact windshield can be breached by a very heavy bird or solid object.
In addition, not only does the windshield protect you from your vehicle, but it also helps deploy the airbags correctly during collisions.
Tendency to Spread
No matter the size of the crack, it has the potential to spread over time. There are a handful of reasons why, but the common ones you’ll face include drastic temperature changes, dirt, and road bumps. This is more likely on vehicles where the windshield is a critical part of the cabin structure, as on some VWs.
Temperature Changes
The constant change in the temperature can accelerate the spread of a crack. For example, during the winter, water could land on the crack and enter it. If the water freezes and expands, the crack will grow. Similarly, during the summer, the windshield heats up and can widen the crack.
Dirt
Dirt and debris could worsen the cracks on your windshield, especially if it’s constantly struck. Some car owners turn to duct tape to cover the cracks, but this might compromise your vision and is a band-aid solution at best.
How Do I Stop the Crack From Spreading?
While you can’t stop the crack from spreading, there are different ways you can slow the process down by using super glue, a windshield repair kit, or by avoiding temperature change.
Take note that these shouldn’t be substituted for the actual repair your windshield needs. Most windshield repair companies have a special procedure for using pressure to fill small cracks with a compound that prevents the crack from getting worse.
Super Glue and Tape
Since super glue contains cyanoacrylate, it’s an effective way to slow down cracks in glasses. The first thing you have to do before applying the glue is to clean the windshield using an auto glass cleaner and paper towels. Afterward, lay out a piece of packing tape over the area to keep dirt and debris from chipping it further.
Windshield Repair Kit
You can buy windshield repair kits at local hardware stores. These kits involve tools and instructions to patch certain types of cracks. While it’s not a 1:1 substitute for actual repairs, it’s often good enough to stop small chips from spreading altogether.
Avoid Temperature Change
The easiest way to prevent cracks from spreading is to avoid sudden temperature changes. As mentioned above, constant temperature change accelerates the spreading process. Experts recommend parking your car under a shade to shield it from the sun or letting it sit in your garage before you visit the auto repair shop.
Can You Drive With a Cracked Windshield?
Generally speaking, you can still drive with a cracked windshield. Having one won’t affect the overall functionality of your car. However, due to the reasons listed above and possible legal consequences, it’s not recommended to do so.
Is It Illegal to Drive With a Cracked Windshield?
Some states have laws in place that make it illegal to drive with a cracked windshield, even if the crack is behind the rearview mirror where you can’t even see it. Each law varies depending on the state, but federal regulations state that you cannot drive with cracks larger than ¾ inch in diameter, two cracks within three inches of each other, intersecting cracks, or cracks that directly obstruct your view.
The fine can get costly since it’s a non-moving violation. In some states, multiple violations will have your driver’s license suspended. One way to avoid getting a ticket is to provide proof that the windshield has been repaired.
Can You Repair a Cracked Windshield?
Yes, you can still have your cracked windshield repaired if the damage is:
- Not blocking the driver’s view
- Chipped with surrounding cracks (1 inch in diameter)
- One or two cracks less than eight inches in length
- Not at the edges of the windshield
Anything beyond those might be unrepairable, meaning you’ll have to get the entire windshield replaced.
Can I Repair a Cracked Windshield by Myself?
It’s possible to repair a cracked window by yourself if you have the right tools and the damage isn’t severe. Some repair kits cost less than $20. However, those don’t include the tools you need, like a syringe to vacuum the air out of the chip.
Most of these kits also have instructions on how to fix the cracks, in addition to useful information such as the difficulty of the damage and how long the process might take. Do note that the outcome of DIY repairs may not be polished, so it’s still recommended to seek professional help.
Final Thoughts
A small crack on your windshield deserves almost the same attention as engine failures or ignition issues. Identifying the issue and nipping it in the bud could save you time and money in the long term. Letting the crack spread