CSA and Tires

Addressing confusion on CSA policies for tire maintenance requirements.


We have seen gauges that are 20 psi off.

Tire Conditions

The violations that carry a “3” severity rating include:

  • Tire underinflated based on load.
  • Regrooved tire on the steer axle.
  • Weight exceeds tire load limit.

Regrooved tires are primarily used by bus fleets and are not an issue for trucking fleets.

Exceeding a tire load capacity is never suggested for tires, and is clearly illegal.

Tire Underinflation

The one violation on the aforementioned list that can, and probably will, affect many fleet SMS scores is tire underinflation. Every industry study shows that tire underinflation is a widespread issue, especially on inside duals and trailer tires.

The dilemma here is that nobody has clearly delineated a definition of underinflation. Is it 10 percent, 15 percent, 20 percent or even higher?

Is underinflation based on what is written on the tire sidewall or is it based on the fleet’s tire air pressure specification?

Because of the ambiguity surrounding how underinflation is determined, a fleet could rack up violation points fairly quickly as enforcement officers use their criteria to determine that tires on an 18-wheel rig are underinflated, assigning three points for each one that is.

CSA Scoring

The official CSA “score” is quite involved when it comes to tires. Basically, here is how it works.

  • CSA assigns weights to time and severity of violations based on a relationship to a crash risk:

+ Last 6 months = 3 x weight.

+ 6 to 12 months = 2 x weight.

+ 12 to 24 months = 1 x weight.

  • BASICs violations are ranked on scale of 1 to 10 – with 10 being the worst, and weighted by severity - i.e., relationship to a crash.
  • Four BASICs have two additional points added: Fatigued Driving (Hours-of-Service), Driver Fitness, Vehicle Maintenance and Cargo-Related.

Scoring example 1: Underinflated tire and less than 6 months since the last incident.

3 points for underinflation + 2 points for the Vehicle Maintenance BASIC = 5 subtotal x 3 for the time weight multiplier = 15 total tire violation score.

Scoring example 2: Flat tire and 6 to 12 months since last incident.

8 points for a flat tire + 2 points for the Vehicle Maintenance BASIC = 10 subtotal x 2 for the time weight multiplier = 20 total tire violation score.

Not Clear

It is very clear that the point total associated with underinflated, flat and low tread depth tires can quickly add up.

Drivers will not want to be associated with fleets that do not have a serious tire program because points are assessed to both fleets and the individual drivers.

To summarize the CSA program as it relates to tires is very easy: It is clearly not totally clear.

  • The definition of an underinflated tire is an unknown.
  • There is no consensus on when a tire is really considered flat. Is it 80 percent under fleet specification or 50 percent of the maximum pressure of what is written on tire sidewall?
  • Inspectors need to be trained on accuracy of pressure gauges and tread depth gauges, where to measure tread depths and gauge calibration.
Al Cohn is a 34-year veteran of the trucking industry. He spent 28 years with Goodyear Tire in Akron, OH, in a variety of assignments related to commercial tires. In December 2005, he joined Pressure Systems International (PSI), San Antonio, TX, as its director of new market development and engineering support. Cohn is a frequent industry speaker and an active member of SAE, ATA and TMC. In 2001, he received the Silver Spark Plug Award, TMC’s highest honor for his contribution to the industry.

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