TP 14665 E
Vehicle Safety Advisory
V 2021-01 E
December 09, 2021
Motor Vehicle Safety Directorate
Information: 1-800-333-0371
Panoramic sunroofs are a popular option on many vehicles. These sunroofs are larger than earlier models, and the glass on some of them can cover the entire roof.
Figure 1: Vehicle with a panoramic sunroof
Since 2012, Transport Canada has been receiving a growing number of complaints of shattered sunroof glass not caused by an impact. Some drivers report they were startled by the loud noise of shattering glass, and pieces of glass fell into their vehicle.
What causes a sunroof to shatter?
Sunroof glass breakage can sometimes be due to manufacturing defects. Transport Canada documents all defect complaints. Where vehicle defects are found, the department requires vehicle manufacturers to correct the problem with a safety recall.
However, Transport Canada has found that, in most cases, sunroof glass breaks are due to impact damage, not because of a defect.
During harsh Canadian winters, road maintenance crews spread salt and gravel on roads to help keep them clear and dry. Today’s large sunroofs make it more likely that an airborne projectile, like a piece of ice, gravel, rock, or other debris, will be kicked up by another vehicle and hit and damage your sunroof.
All glass (including sunroofs) can break on impact. However, it’s also possible for an impact to simply damage the glass. In these cases, the glass may not break until later on, usually due to temperature shifts or a vehicle jolt. This can give the impression the glass shattered for no apparent reason.
Number of shattering sunroof complaints
Though the number of shattered sunroof complaints are rising, when you consider the number of vehicles on the road, it's still quite a rare event.
Since 2012, Transport Canada has received 803 complaints about shattering sunroof glass.
Figure 2: Number of shattered sunroof complaints received by calendar year. 2021 numbers are reports as of November 30, 2021.
Text version
| Year | Total |
|---|---|
| 2002 | 1 |
| 2003 | 2 |
| 2004 | 0 |
| 2005 | 1 |
| 2006 | 1 |
| 2007 | 0 |
| 2008 | 2 |
| 2009 | 2 |
| 2010 | 5 |
| 2011 | 4 |
| 2012 | 12 |
| 2013 | 20 |
| 2014 | 29 |
| 2015 | 81 |
| 2016 | 109 |
| 2017 | 158 |
| 2018 | 114 |
| 2019 | 158 |
| 2020 | 49 |
| 2021 | 59 |
* 2021 total as of November 30, 2021
While complaints have increased over recent years, these follow the general trends of more and larger sunroofs in vehicles, and more vehicles on the road. However, complaints decreased in 2020 and 2021 likely due to COVID-19 lockdowns and travel restrictions resulting in vehicles being used less.
Canadian standards require automotive glass to be designed in a way that, if the glass breaks, its particles are not likely to injure people.
Tempered glass, which is often used in sunroofs, rear and side glass, is designed to shatter into small glass particles with relatively dull edges, not large fragments with sharp edges. These small particles of glass pose little risk to drivers and passengers. That being said, if you handle this broken glass, it could cause minor cuts.
A review of Transport Canada complaints shows there have been no serious injuries reported as a result of a shattering sunroof.
Figure 3: Broken house glass. When broken, it splinters into large, jagged shards with sharp edges. This makes it unsafe for use in vehicles.
Figure 4: Broken tempered glass. This type of safety glass is used in vehicles. The tempering process causes the glass to crumble into small particles with dull edges when it breaks. These small particles are less likely to injure you.
What can I do to prevent my sunroof from shattering?
A shattered sunroof can be an annoying and costly to repair. Unfortunately, there are no good ways to keep sunroof glass from breaking. While window films that protect the glass do exist, we have found that they can cause large chunks of broken glass to fall inside the vehicle or fly off and hit other road users.
One way to protect your sunroof's glass is by avoiding scratching the glass when loading or unloading a roof rack. If the glass is scratched, it could progress into a crack and eventually cause the glass to shatter.
If you notice your sunroof glass is damaged, but hasn't shattered yet, you should speak with your dealership or a glass repair facility to see if action should be taken.
If you believe your vehicle's sunroof may have shattered due to a manufacturing defect, please call Transport Canada's Defect Investigations Section at 1-800-333-0510, or complete our online complaint form. If you have photos of the shattered sunroof, Transport Canada investigators may wish to examine them. The department reviews all defects complaints.