The most surprising finding was that when the magazine marked the packages "fragile," they appeared to receive more abuse.
Derene said he was "surprisingly impressed" by the Postal Service," but when they contacted the shipping companies for comment, he learned that while the U.S. Postal Service has its own sorting and delivery systems, Express Mail flies with FedEx.
"So our package experienced both the most and the least abuse while on the same airline. This raised an unanswerable question: Does the USPS have white-glove handling that offsets FedEx's turbulent planes, or did our package just happen to catch a few smooth rides?" he asked in his article.
Derene said that while he expected the experiment to provide clarity, it actually raised more questions than they had when they started. But he did say that he came away with at least one key, firm finding: Pack your parcels carefully.
"The biggest thing I got out of this is ... make sure you insulate and protect your packages well," he said. "They get jostled around a lot. All of the companies, we talked to all of them afterwards and all of them said, 'Look, we do our best.' And I'm sure they do, but it's an industrial environment and there are a lot of machines involved and a lot of movement involved."
For more information on how the shipping companies performed, click on to the next page or visit Popular Mechanic's website.
FLIPS (Number of position changes per trip)
FedEx: 7.0 UPS: 4.0 USPS: 12.5
SPIKES (Average number of acceleration spikes exceeding 6 g's per trip)
FedEx: 3.1 UPS: 2.0 USPS: 0.5
TEMPS (Highest and lowest temperatures (Fahrenheit) per trip)
FedEx: 77.46 degrees (high); 51.45 degrees (low) UPS: 77.98 degrees (high); 51.18 degrees (low) USPS: 79.30 degrees (high); 47.44 degrees (low)