Backing up can be a tricky cognitive problem. I suspect (on no particular evidence) that being good at backing up is not hugely related to g, the general factor in intelligence. So, a specific test of backing up skill could be useful. Backing up a trailer is harder than backing up car, but for applicants to truck driver training programs, a parallel parking test using the applicant's own vehicle might make a good first cut (along with paper and pencil tests). If somebody is bad at parallel parking his or her own vehicle, that might indicate something about the likelihood that they'll wash out of trucking school.
Parallel parking isn't easy, even for professional heavy equipment drivers. From the June 2005 issue of Concrete Producer trade magazine:
Back for its third year at World of Concrete, the John Deere Load America competition has become a popular mainstay outside the Las Vegas Convention Center.
Participants were more eager than ever to hop inside the cab of a John Deere 544J front-end loader and take on a formidable obstacle course for some terrific prizes. Participants received points for successfully executing a variety of maneuvers such as backing up, parallel parking, and driving up a ramp to drop a ball into a barrel.Of all the obstacles, parallel parking usually give participants the biggest challenge ...
As a society, we don't benefit when people wash out of expensive training programs for predictable reasons.
So, why wouldn't a trucking firm at least consider a parallel parking test for job applicants?
Well, how about "disparate impact?" What if a legally protected demographic group such as, say, women turned out to pass the parallel parking test at less than four-fifths rate of the highest scoring demographic group?
I have no idea who tend to be the best and worst parallel parkers, but I wouldn't be surprised if women are below average at it. A key part of parallel parking is psychological rather than cognitive: it's the feeling that you damn well deserve to block traffic while you take your time so you can do it right the first time. (I'm reminded of something a PGA rival said about why Arnold Palmer sank so many crucial 20 foot putts: That Arnold had more confidence barely begins to describe the gap between him and the lesser mortals on the golf tour. The key was that Arnold just felt he deserved to sink 20 foot putts.)
And big rig drivers face much harder parking challenges. There's a reason that truck drivers in popular culture are stereotyped as insensitive: sensitive types who worry about how they are blocking other drivers while they try to backup through a three-point reverse turn into an alley 18" wider than their trailer tend to get flustered and mess up.
In a sane, effectual society, questions of disparate impact would be answered once and then we'd move on. We'd check to see if, say, parallel parking was a valid test that provided useful information about who is likely to become a good truck driver. If the parallel parking test had a disparate impact on women, we'd check to see if the unlikely might be true and the test had something odd about it that made it less valid for women. But, once it turned out that, yes, women tend to make lousier truck drivers and, yes, this test merely reveals that, we'd move on.
And yet the Ricci fireman promotion test case shows that when it comes to disparate impact, we don't move on. Fireman promotion tests have been studied and litigated longer than many of you reading this have been alive. Nothing ever changes. But we're all supposed to act like it could change at any minute. That provides a lot of money to discrimination lawyers (e.g., Barack Obama), testing firms, consulting firms that pick the testing firms, etc. etc.