Commercial trucking fleets are spending a lot of time these days trying to meet all of the rules and regulations in FMCSA's rollout of CSA (Compliance, Safety & Accountability), which officially began December 2010.
The Commercial Vehicle Safety Administration considers a tire flat when the measured air pressure is less than 50% of the maximum tire pressure molded into the tire sidewall. Because this measurement differs from most fleet specifications, a fleet could rack up points fairly quickly.
Tire dealers need to take the time to understand the newest government safety improvement program for commercial vehicles. Fleets and drivers are both affected by CSA. A high score, which is bad, can lead to government intervention for the fleet, and for a driver it could mean potential serious difficulty in finding/keeping a job.
Since tires play a major role in the CSA scoring system, tire dealers can take this opportunity to provide valuable tire support to their fleet customers.
The latest Safety Measurement System methodology document has been published by FMCSA and can be downloaded by clicking here
. This 123-page document details and quantifies how the SMS score is calculated. The SMS score allows the enforcement community to identify specific safety problems for fleets, and will be used to continuously monitor on-road performance to determine whether a carrier’s safety performance has improved or if intervention is warranted.
Tires have a major impact on a fleet’s SMS score. They fall into the vehicle maintenance category of the Behavior Analysis & Safety Improve-ment Category (BASIC) system. The violations associated with tires can be found on pages A19-A20 in the appendix of the referenced SMS Methodology document.
FMCSA tire violations are found in Section 393.75 of the code. FMCSA has attached a violation severity number to be used in calculating the SMS score; depending on the specific tire issue, either an (8) or a (3) will be applied for each violation.
Violations that carry the (8) severity rating include:
Flat tire or fabric exposed
Ply or belt material exposed
Tread and/or sidewall separation
Flat tire and/or audible air leak
Cut exposing ply and/or belt material
Steer tire tread depth less than 4/32-inch
Drive, trailer, dolly tire tread depth less than 2/32-inch
It is obvious that a driver walk-around vehicle inspection that includes tires should easily identify these high severity violations. But it is not always simple to inspect those inside dual tires. Among other things, bad weather complicates this inspection.
Tire dealers are being called upon to train fleet service techs and drivers on the proper use of both tread depth and inflation pressure gauges. Tire professionals take tread depth readings all the time and it does not seem like any big deal. But drivers and fleet technicians need training to understand some of the tread depth gauge basics:
Calibrate gauge (make sure the gauge measures 0 when you check on a flat surface)
Readout can be both 32nds and millimeters (read the correct line)
Take measurement in a major groove
Do not measure on top of a stone ejector in the bottom of a groove
Pressure gauges are another story. Using a calibrated pressure gauge is critical. The most common stick-type pressure gauges are notorious for giving incorrect readings after a few drops on the hard concrete. The very inexpensive metal spring inside the gauge can change its stiffness coefficient after a few drops to the concrete floor and also with changes in temperature.
A tire with an audible air leak has a large puncture and will lead to an eventual tire failure. Just looking at a tire on a vehicle will not determine if a tire is “flat.” It must be measured with a calibrated tire inflation gauge.
Tires showing cuts and exposed steel or fabric are not recommended to be running on vehicles.
Running tires with tread depths below 4/32-inch for a steer and 2/32-inch for all other wheel positions has been a way of life for just about forever, but is clearly not suggested. A simple tread depth gauge will identify low tread depth tires.
The Commercial Vehicle Safety Administration considers a tire flat when the measured air pressure is less than 50% of the maximum tire pressure molded into the tire sidewall. The current industry standard followed by most fleets in considering when a tire is flat and needs to be removed is 20% below the fleet air pressure specification.
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 usually an issue for trucking fleets.
Exceeding a tire load capacity is never suggested for tires and is clearly illegal.
The violation on this 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%, is it 15%, or maybe 20% or even higher? And, is it 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 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.
In addition to points adding up for various safety violations, there are also added points associated with frequency. There are penalty points associated for specific issues. The scoring system assigns weights to time and severity of violations based on relationship to crash risk:
> last 6 months = 3 x weight
> 6-12 months = 2 x weight
> 12-24 months = 1 x weight
Let’s take a look at a “flat” tire scoring example. A 295/75R22.5 trailer tire has a measured pressure of 55 psi. The information on the sidewall shows that the tire has a maximum pressure of 120 psi. The roadside inspector will probably use the 50% rule.
Since the actual tire pressure (in this case 55 psi) is less than 60 psi (half the pressure molded into the sidewall) the tire is considered flat and assigned 8 points. Let’s also assume that this is the second tire violation within the last 12 months.
Flat tire, second violation in last 6-12 months:
8 Points for flat tire
+ 2 Points for vehicle maintenance
= 10 Subtotal
x 2 time-weight multiplier
= 20 Total Tire Violation Score
You can see with just this simple example how the official “score” can increase very quickly.
Drivers are now taking a very serious role in equipment with tire issues. If they get pulled over with a flat or underinflated tire, the SMS points will affect the fleet and also will show up on the driver’s SMS point total.
All the SMS points stay with the driver for three years, so they have a stake in proper tire maintenance, too. In addition, the points are available for the world to see by going to the CSA website. It is going to be very difficult for a driver with a high point total to find future employment.