.png)
Top 5 Common Causes of Commercial Vehicle Breakdowns (and How to Prevent Them)
Commercial vehicle breakdowns are common but largely preventable through proper maintenance and smarter driver habits.
Commercial vehicle breakdowns are costly, dangerous, and a major stressor for drivers. They are also common, with three in 10 commercial vehicles experiencing a breakdown each year.
One of the best ways to avoid breakdowns is to keep vehicles properly maintained. This will, in turn, help keep drivers safer, as a direct causal link has been established between neglecting vehicle maintenance and being in an accident, according to the Federal Motor Carrier Safety Administration (FMCSA).
In addition to decreasing safety risks for their drivers, fleets can also expect to save a lot of money by regularly maintaining their vehicles: Preventing just one breakdown saves an average of $300 to $500 in towing and labor costs alone, translating to $50,000 to $100,000 per year in annual savings for a 50-vehicle fleet.
There are also simple actions drivers can take to help prevent vehicle breakdowns, such as adjusting their driving and performing “symptom” checks.
Top 5 Causes of Commercial Vehicle Breakdowns
The top breakdown causes are listed below in the order of how commonly they occur. However, keep in mind that commercial vehicle breakdowns often have more than one cause, further highlighting the importance of keeping vehicles maintained.
Studies show that logbook violations, leading to deferred maintenance and rushed inspections, are equated with higher breakdown rates.
In addition to keeping up with regular maintenance, there are also simple actions drivers can take to keep their vehicles on the road longer, and keep themselves safer. For example, regularly checking the battery and performing weekly tire checks can help rule out almost one-third of the causes of commercial vehicle breakdowns, while protecting against more than one-third of semi-truck accidents.
- Battery Failure
Earning the top spot is battery issues, being the cause of nearly one in five (18 percent of) commercial truck breakdown call-outs. The data analyzed covered many vehicle types and years, making battery failure a systemic issue.
In many cases, fleet operators will replace batteries if the vehicle won’t start, but if the alternator is the problem, the new battery will drain quickly, leaving the core issue unresolved. Mechanics will check the alternator output first (which should read 13.5-14.5V at idle) as a diagnostic.
Driver behavior can also influence battery life. Excessive idling, vibrations from harsh driving (including hitting potholes), and running electric accessories like lights and refrigerators with the engine off can all drain the battery.
- Tire Blow-Outs
Coming in at second place on our list is tire defects, causing 13 percent of commercial vehicle breakdowns. This is also a particularly dangerous issue, with tire defects being the cause of nearly one in three semi-truck accidents (32 percent), according to FMCSA’s Large Truck Crash Causation Study.
Simple math helps explain the issue, with trucks having many more tires than the average vehicle on the road.
“Tractor trailers have 18 tires, or 14 more opportunities for a blow-out, than most passenger cars, which typically have four. The increased number of wheels also significantly increases the maintenance burden on truck owners and operators,” the FMCSA reports.
Checking tire pressure and tread weekly, instead of only during scheduled maintenance, can help prevent breakdowns and resulting accidents.
These breakdowns are not only dangerous, but also becoming more expensive. This is because today, commercial vehicles are more frequently shipped without spare tires. So if a puncture happens, a $300+ service call is often required to tow the vehicle and fix the issue—an issue that used to cost closer to $50 and was fixed by the driver, in about 15 minutes.
- Clutch & Other Mechanical Issues
Next on our list of common causes of commercial vehicle breakdowns is clutch failures, accounting for 5 percent of breakdowns.
Driver behavior, via “riding the clutch,” and/or overloading the vehicle can halve the clutch’s lifespan, from 100,000 miles to 50,000 miles.
Other common mechanical issues include alternator failures (4 percent) and starter failures (3 percent).
Ignoring symptoms of gearbox failure can be catastrophic. What could be addressed through early intervention at about $500 to $1,500 in repair costs can escalate to $3,000 to $8,000 in repairs.
- Diesel Fuel Contamination
Causing 3 percent of commercial vehicle breakdowns—and becoming more common in recent years—is diesel fuel contamination. This issue causes difficulty starting the vehicle, misfiring, and smoky exhaust, requiring a full flushing of the system to resolve.
However, a faulty electronic control unit (ECU) will often display the same or similar symptoms, requiring specialized diagnostics, which roadside services often can’t provide.
Fleets can help prevent diesel fuel contamination through fuel cap labeling and educating drivers on where to source trusted fuel.
- Driver Error/Fatigue & Poor Visibility
Finally, driver error and fatigue and poor visibility cause 2 percent of commercial vehicle breakdowns. However, these would probably be better classified as accidents.
Aggressive driving is particularly dangerous, named as the cause of 7 percent of truck accidents in 2023, while also being hard on the truck. Brakes, tires, and suspension all wear faster due to aggressive driving.
“Most accidents involving commercial trucks aren’t just ‘driver messed up.’ They’re: Driver + company pressure, Driver + bad maintenance, Driver + unsafe loading, or a mix of all of the above,” reports an analyst at Bennett Legal, a Dallas-based law firm that specializes in commercial truck accidents.
Brian Omps Towing & Repair: Proudly Serving the Shenandoah Valley Area for 25+ Years
Our fast, reliable, round-the-clock services include light-, medium-, and heavy-duty towing, recovery, roadside assistance, and truck repair.
