Here is an excerpt I found on retread.org:
BUT HOW ABOUT SAFETY?
The safety of today’s retreads has been proven beyond a doubt by millions of vehicles over billions of miles worldwide. Airlines, both commercial and military, school and municipal buses, small package delivery services such as DHL, FED EX, UPS, the U.S. Postal Service and postal services in many other countries routinely and safely use retreads. Taxis, race cars, Fire Engines and other emergency vehicles also safely use retreads as to trucks and other types of vehicles in both the private and public sectors around the world.
THEN WHY DO WE SEE SO MUCH TIRE DEBRIS ON OUR HIGHWAYS?
Unfortunately, many people believe that tire debris (road alligators) on our highways is caused by retreads that have come apart. But the facts are different from the perception that most people have. Nearly all of the tire debris on our highways comes from tires that have been improperly maintained.
Underinflation, closely followed by misaligned vehicles, mismatched tires on dual wheel positions on trucks, improper tire repairs, tires with less than the legal limit of tread remaining and overloading of vehicles are the main causes of tires failing and throwing rubber pieces all over the highway. It doesn’t matter if the tire is a retread or one that has never been in a retread factory, if it is not properly maintained, if will fail given enough time.
To blame a retread for tire debris on our highways is the same as blaming a vehicle for an accident caused by a drunk driver. The blame is simply misplaced.
IS THE SAVINGS REAL WHEN RETREADS ARE USED?
Yes it is. You can often save as much as 50% over the cost of a comparable new tire, without sacrificing safety, performance or handling. Since tires are one of the highest costs of operating any fleet, whether it is a fleet on one truck or one thousand trucks, by using retreads you will make very significant savings when buying tires. In the U.S. there is even a Federal Executive Order (13149) MANDATING the use of retreaded tires on many government fleet vehicles.
And another...
If you are certain that tire debris on our highways (also known as rubber on the road or road alligators) is caused by retreads, you need to read the National Highway Traffic Safety Administration (NHTSA) Commercial Medium Tire Debris Study just released.
It is a 214 page document and should prove once and for all that the true cause of tire debris on our highways is NOT because of retreads. The study contains a huge amount of important information about the true causes of tire debris, but this makes it clear that retreads are not to blame!
For those who have a serious interest in the findings, see page 188 for the Overall Study Conclusions (10.4). We knew it all the time, but it's nice to see that the federal government agrees with us!