Marco had the best first-attempt delivery rate in the entire fleet. Thirty-four years old, eight with the company, zero accidents, never a customer complaint. When the morning-shift supervisor role opened up, the choice felt obvious to everyone. Six months later, two of the twelve drivers on his shift had quit, delays were up 22%, and Marco was spending his evenings calling his old coordinator for advice.
This story, with different names, plays out every year in hundreds of road transport companies. It’s the operational translation of the Peter Principle, the observation formulated by sociologist Laurence J. Peter in 1969: in a hierarchy, every employee tends to rise to their level of incompetence.
For years it was treated as a witty aphorism. Today we know it’s a measurable, costly, predictable phenomenon.
The data: pre-promotion performance predicts the opposite
The most rigorous study ever done on the subject was published in 2020 in the Quarterly Journal of Economics by Alan Benson, Danielle Li, and Kelly Shue. They analyzed 53,035 salespeople at 214 American companies between 2005 and 2011. Of these, 1,531 were promoted to sales managers in the observed period. The result is sharp and counterintuitive:
- A salesperson who sold twice the average was about 15% more likely to be promoted in any given month.
- But among the salespeople actually promoted, pre-promotion performance was negatively correlated with managerial quality: those who sold more tended to make worse managers.
The mechanism is simple. The skills that make someone an excellent individual contributor — focus, autonomy, obsession with personal results, deep technical knowledge — are largely orthogonal to managerial skills: asymmetric communication, delegation, conflict management, reading aggregate data, patience in coaching.
Applied to fleets: the best driver is almost never the best supervisor. They’re good at driving, not at making others drive well.
Why it happens anyway: three structural reasons in transport
Knowing it’s a mistake isn’t enough to avoid it. In transport SMBs, the “Marco-style” promotion remains the default for three specific reasons.
1. Lack of career alternatives
In the Italian collective bargaining agreement for logistics and freight transport, the career levels available to a qualified driver run out quickly. Above level 3, the only way to grow economically and gain professional recognition is to move into a coordination role. There is no formally recognized “senior driver” or “fleet trainer” specialist track. If you want to keep your best driver in the company, you’re effectively forced to make them a supervisor. The same pattern repeats across European labor markets.
2. Asymmetric visibility of skills
Driving performance is easily measurable and visible: kilometers driven, deliveries completed, fuel consumption, tracked driving behavior. Managerial skills — handling a conflict between two drivers, correctly interpreting an anomaly report, communicating a planning change without triggering panic — are invisible until someone puts them in front of you.
The result: you promote based on what you see, not on what will matter.
3. Time pressure
When a supervisor quits, the operational gap needs to be filled immediately. There’s no time to run an assessment, to test the candidate on a managerial task before assigning the role, to organize a structured shadowing period. You appoint whoever is “ready” — meaning, whoever is already there, has experience, and is available — and you hope they’ll learn on the job.
International data says this is a bet you lose 6 times out of 10: research by the UK’s Chartered Management Institute shows that about 60% of new managers fail within their first 12-24 months. And 82% reach the role without any formal management training.
Five signs the supervisor is in trouble (first 90 days)
You don’t need to wait a year to know you’ve promoted the wrong person. The signs surface in the first three months, are predictable, and can be diagnosed without formal interrogations. Here are the five I see most often in fleets.
1. The new supervisor still does operational work. They go out on deliveries “because a driver is missing,” download tachograph data “because they’re the only one who does it right,” handle customer complaints personally instead of delegating. It’s the classic symptom of someone who can’t leave the comfort zone where they were competent. A fleet doesn’t scale if the supervisor also drives, dispatches, and handles customer service.
2. Shift meetings get skipped or derail. They call the team for 6:30 AM twice, skip the third “because we know what to do anyway.” Or the meeting turns into a technical monologue on specific problems, with no clear priorities. Communicating with a group of 8-12 people requires different skills than coordinating with a dispatcher.
3. Turnover under them rises. Driver resignations in the first six months of a new supervisor are the rawest and most informative KPI. In a 12-driver fleet, losing one is normal; losing two in three months is an alarm signal; three is a confirmation.
4. Data is used to justify, not to decide. A good supervisor looks at the fleet KPIs to understand where to intervene the following week. A struggling supervisor looks at the same data only when asked about a performance drop, and uses it to explain why “it’s not their fault.” It’s a subtle but diagnostic shift in posture.
5. Younger drivers avoid them. In a healthy fleet, new hires turn to the supervisor for clarification, training, operational support. When instead they bypass the hierarchy and ask the operations director or a senior peer directly, it means the supervisor isn’t recognized as a reference. It’s an informal authority problem that’s hard to recover from without structured intervention.
What to do before promoting (and after)
There is no foolproof test to predict who will be a good supervisor. But there are practices that significantly reduce the error margin.
Before the promotion: give the candidate a time-bound pseudo-coordination task. Example: for three months, they’re responsible for onboarding a new driver, from process training to first-two-weeks performance review. It’s a realistic, low-risk assessment that shows managerial skills in a controlled context. If the candidate struggles with a single new driver, they won’t be ready to manage ten.
Immediately after the promotion: plan a structured shadowing period of at least 60 days with the outgoing supervisor or a coordinator from another shift. Not a three-day “handover,” but real shadowing where decisions are made together, with weekly debriefs. The cost of those 60 extra days is a fraction of the cost of a failed supervisor replaced six months later.
After the first 90 days: do a formal review, with objective metrics (turnover, delays, complaints) and feedback collected anonymously from team members. If the signals are negative, talking about it openly is mandatory. In some cases, the smartest move is to propose a return to the previous role — without financial penalty — and add a management training path before a second attempt. The most recent mitigation policies research shows that timely “selective demotion” is one of the most effective strategies to reduce the costs of the Peter Principle.
The question the operations director should be asking
When the time comes to promote the next supervisor, the right question isn’t “who’s my best driver?” It’s: “who among my drivers would best handle a situation where two colleagues clash over who gets the longer route?” The answer will often be a different person than whoever sells — or delivers — the most.
Understanding this difference is the first step in building a team that not only works today, but keeps working when it has to grow. For those who want to dig into the phenomenon with data, the article Peter Principle in numbers: what the empirical research really says collects the most relevant studies and their concrete application to fleet management.
In the meantime, the practical rule stays simple: before you promote, test. After you promote, support. After 90 days, measure. And if the numbers tell you that you got it wrong, have the courage to step back before your drivers do — by quitting.