Back to top

For drivers to operate a commercial motor vehicle (CMV) in a safe manner they also need to understand how heat affects the operation of the CMV. Two areas that drivers must pay attention during their inspections are the engine coolant and the tires!

Engine Coolant

Approximately 8 years ago the OEM truck manufactures introduced extended life coolant (ELC) into the industry!  With each EPA change the operating temperature of the engine has increased 10 to 15 degrees.  It is estimated that 50% of all engine failures are associated with an overheat condition of the engine. With today’s emission systems an engine running low on coolant runs the risk of damage the emission components such as the exhaust gas recirculation or EGR. The benefit of using ELC is the fact that you can improve the engine's heat transfer rate by 12 to 13 percent over conventional anti-freeze.

Diesel Exhaust Fluid DEF

There is a quality level sensor in the DEF tank thank can be affected by extreme heat.  It is recommended that you keep the DEF tank full as possible to keep the sensor cool in extreme heat conditions.

During the pre-post trip inspection driver should:

  1.  Make sure that the coolant level is within range of the marking on the side of the coolant reservoir.
  2. If the coolant level is low contact your Idealease service provider immediately for direction.  ELC coolant should be a red/orange color and should be free of dirt, debris, rust, and other contaminants. Do NOT ELC with mixed conventional anti-freeze!
  3. If when operating a CMV a dash light comes on with an overheat warning immediately pull the unit into a safe parking place and contact your Idealease service provider for direction.  Operating the unit in an overheat situation can severely damage the engine.


During the summer season, when the ambient temperatures can get well over 100° F, and some road temperatures can reach almost 200° F, the heat problems caused by under inflation are more extreme. Tires that are run under inflated will be more prone to failure in these temperatures. A very famous tire engineer once stated, “Heat is to tires as Kryptonite is to Superman” … in other words, it is worst enemy. Taken all together, hot summer temperatures, under inflated tires, heavy loads, and traveling at high speeds (not that this ever happens), and you have a recipe for tire disaster…. that is exactly why you see more alligators on the highway in the summer season.

What can drivers do to minimize tire related issues during the summertime months?

  1. Tire pressures need to be checked more frequently in the summer.
  2. Tire pressures need to be checked when the tire is “cold” and not after operation.  Pressures can increase during operation when “hot” by as much a 15% giving you a false reading.
  3. Inspect tires for punctures and damage during pre-post trip inspections and stops. Tire punctures tend to increase during the summer because the tread rubber becomes hotter and “softer” and acts as a magnet to nails and road debris.
  4. Immediately report to your Idealease service provider tire conditions that need attention.

An Aging Driver Force


As we look into the future, the continued challenge of a driver shortage looms as a “perfect storm”. There are many variables that would have an impact on the shortage.  One element of the driver shortage is an aging workforce combined with a decline in the primary demographic group that comprises the bulk of the driver pool.   As we see freight volumes increase many fleets are having trouble attracting qualified drivers and may be unable to seat trucks or add capacity at a time when freight volumes are growing. If current demographic trends continue, that shortage of truck drivers could increase to 111,000 by the end of the year. Over the next decade, the trucking industry will need to hire a total 890,000 new drivers, or an average of 89,000 per year. Replacing retiring truck drivers will be by far the largest factor, accounting for nearly half of new driver hires (45%). The second largest factor will be industry growth, accounting for 33% of new driver hires.  As transportation managers we are seeing our driver work force continue to age.  The average age of a truck driver in the United States is over 50 years. Since 2000, the number of truck drivers 55 or older has surged 19%, to about 616,000, according to the federal Bureau of Labor Statistics. Truck companies with baby boomer drivers insist their safety record is at least as good as that of younger drivers.  This is absolutely a segment of our driving force that we need and depend on.    As all of us age, we do not physically or mentally age at the same rate.

The FMCSA does not have a maximum age limit for drivers of commercial motor vehicles unlike that of the FAA concerning pilots.  All drivers are subject to the medical qualifications of medical certification requirements of CFR 391.

But, the question remains, how do we as transportation managers know when it is time to ask for the keys of a driver that is no longer able to operate safely? 

Here are a few suggestions:

  1. Develop a proactive safety and loss control program with policies and procedure that are not bias to age.
  2. Require all drivers to have physical examinations completed by an FMCSA registered medical examiner who has a relationship with your company.
  3. Develop job descriptions and job requirements for all positions based on actual requirements of the job   activity.
  4. Implement a defensive driver training program with updated training annually for all drivers.
  5. Administer structured check rides at least annually to all drivers to access the driver’s skills and abilities. 
  6. Develop a continuing relationship with all drivers to keep an open line of communication regarding the driver’s ability to complete their driving responsibilities safely.
  7. Be vigilant and observant of the actions of all drivers.