Many months ago, before I was commuting on the bus I started noticing fluorescent green/yellow plastic arrows on the lug nuts of semi trucks wheels. I always wondered what they were but never actually took the time to look it up.
As my bus pulled up this morning I noticed that all the tires on the bus have these things too. A little internet research revealed that these are a 65-cent safety device made by a company called Wheel Check. The idea is the mechanic that tightens the lugs installs these plastic arrows in a simple visual pattern. Then the vehicle operator just has to glance at the tire during their state required walk around and they can tell easily tell if a lug nut is getting loose. What a fantastic and simple invention.
As you can imagine, when lug nuts on big vehicles get loose bad stuff happens. Every year there are multiple incidents of individuals being killed by flying tires in the northwest alone. I Binged it and was instantly depressed by the sad stories of lost one from flying tires.
Wheel Checks are installed on all the Seattle Metro busses, Community Transit busses, Microsoft Connector and Waste mgmt vehicles. Now that you know what’s it called and what it does I bet you notice one this weekend!