The development of regulations affecting commercial motor vehicles and the holders of a Commercial driver’s license has been assigned to the Federal Motor Carrier Safety Administration.  The FMCSA Regulations include windshields, windows and equipment that affect a driver’s view of the roadside and surrounding environment.

Maintaining compliance with these regulations has taken on a new significance for drivers and carriers since the introduction of the FMCSA’s Comprehensive Safety Analysis 2010 (CSA2010).  The program methodology was later renamed Compliance, Safety, and Accountability (CSA).  Drivers should maintain a familiarity with the provisions of this program.  The assignment of CSA severity weight points to drivers’ scores and carriers’ safety ratings occurs when non-conformance with the safety regulations is observed during roadside inspections.  Unacceptable windshield conditions could draw a law enforcement officer’s attention to you and trigger a roadside inspection.  Understand the following requirements and avoid a blemish on your record.


  • The area of concern with a truck windshield does not include a 2-inch border at the top, a 1-inch border at each side of the windshield or windshield panel and the area below the top of the steering wheel. 
  • The vision of the driver must not be obstructed by discoloration or damage, within the remaining portion of the windshield. 
  • The unacceptable damage discussed in the regulations is a rock chip greater than ¾ inch or a chip that cannot be covered by a nickel.  A small rock chip that is less than ¾ inch but is within 3 inches of another similarly or greater sized chip, or a crack would also be a defect.  Any two cracks that intersect are also a defect.



  • CMV windshields, and the driver and passenger windows, may be tinted providing that 70% of light be allowed to pass through the window under normal light conditions.  Two important factors that must be considered before an owner decides to tint a truck window are: (a) Clear tempered glass allows only 88% - 92% light to pass through.  (b) Many OEM truck windows receive tint at the factory that allows close to the minimum legal at 76% - 78% light transmittance.
  • If owners apply tint what they believe to be legal at 30% blockage, light transmission through clear glass would be an unacceptable 62% -64%.  Worse yet, applying the same tint to a typical factory tinted window would allow less than 55% light to pass through.
  • Many drivers tint their windows because they are worried about the affects of bright sunlight on their eyes and skin.  A viable and legal solution to offset the harsh affects of the sunlight would be clear, ultraviolet blocking window film that is readily available at $2 - $3 per square foot.




  • The regulation concerning windshield obstructions is quite clear.  FMCSA regulation, §393.60(e) states, in part:  Antennas, transponders, and similar devices must not be mounted more than 6 inches below the upper edge of the windshield. These devices must be located outside the area swept by the windshield wipers, and outside the driver's sight lines to the road and highway signs and signals.
  • Commercial Vehicle Safety Alliance (CVSA) inspection decals and stickers and/or decals required under Federal or State laws may be placed at the bottom or sides of the windshield.  Such decals or stickers must not extend more than 4 ½ inches from the bottom of the windshield and must be located outside the area swept by the windshield wipers, and outside the driver's sight lines to the road and highway signs or signals.
  • It is a common practice to attach GPS receivers or pre-pass and toll road transponders in an unauthorized area of the windshield.  Drivers should be aware that this practice is non-compliant with the regulations.




  • Each bus, truck, and truck-tractor manufactured on or after December 25, 1968, must have a windshield wiping system. 
  • Each of these vehicles must also have a windshield washing system.  Windshield washing systems must contain washing fluid in order to be considered a working system. 


Any of the aforementioned defects could result in a violation with a fine and associated CSA points.  Additionally, an experienced mechanic performing the annually required DOT Periodic Inspection should fail the inspection if cracks or chips adversely affect the driver’s vision.  The inspection should also fail if the wiper is inoperative or has missing parts that render it ineffective.

The worst-case inspection scenario a driver faces is a roadside inspection that results in an out of service order for a laden truck on a tight schedule.  A defective windshield wiper on the driver’s side during inclement weather requires an out of service order.  The Commercial Vehicle Safety Alliance (CVSA) out of service criteria places in a restricted service condition any CMV that has a crack in the windshield area lying in the sweep of the driver’s wiper blade. Follow these requirements to keep your record clean and to keep you on the road.


Comments (12)

Terry OConnell

After a 30 year U.S. Coast Guard career, Terry and his wife René, obtained their CDLs and began a 19 year adventure in expediting. In 2008, he entered his third career working for the Safety Department of an interstate carrier.

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Can't find a clear answer anywhere. What are the laws for mounting a "turbo wing" or bug deflector on the end of hood? Line of sight or height req?

December 06, 2017 6:28:13 AM

Our company has installed incident cams at the top left of the passenger side windshield in some trucks and are pushing to install more. Because they are mounted in the sweep of the right side wiper, I wonder does that constitute a violation?

July 21, 2014 10:08:08 AM

Good and informative article. I will go out and make sure I am compliant. Thought so before reading this, better to be sure. Thanks

February 23, 2013 20:23:40 PM

I can see the logic in these regs.

February 15, 2013 10:42:00 AM

Jimmy: One of our members purchased a chrome IFTA decal holder, fastened that to the dash of his Cascadia and mounted the Large Rand McNally truck friendly GPS on that and thereby avoided the suction cup on the windshield

November 19, 2012 12:12:03 PM

After reading this article I actually measured mine to find I was an inch over the current regualtion given by Terry. Even if mounted at the very top of the windshield, it appears given that nothing is to be lower than 6" from the top, that my 7" GPS would be considered illegal. I have moved it to an out of the way area on the dash. I suppose with GPS devices reaching sizes of small TV's now, it is going to be harder and harder to safely mount aftermarket GPS devices such as these. Thanks!

November 18, 2012 20:26:04 PM

After Terry told our group (Trucking Solutions Group) about the regulation regarding the placement of GPS type devices to the windshield, I had to move my Prepass device and GPS. I also utilize a dashboard camera mounted to the windshield so re-arranging these devices to be compliant was a little challenging.

With regards to the tinting issue, I have installed home made screens on my truck windows to keep bugs out while sleeping with the windows open. During an inspection, the inspector intended to cite me for the inability to see me (enough for his satisfaction) through my driver's window when he approached. I had to show him the regulation he was going to cite me for in order to prove to him that the regulation refers to the tinting of the windows and does not in any way refer to or mention screens installed on those windows. He relented. Thanks, Terry.

November 12, 2012 13:18:14 PM

I will be moving my GPS. Great information and Thank you for helping save my csa score.

November 08, 2012 11:03:59 AM

This was great information.. I was in a DOT Inspection in Deming NM several years ago I had my side windows tinted to the legal limits so I thought. After 45 minutes of going through every inch of the truck and trailer the Officer could not find anything wrong and it was obvious he wasn't satisfied with not finding anything wrong or out of order, Until he was about to fill out the paper work and looked up and asked me if my windows were tinted? Yes they were that light he got the biggest smile on his face ran inside the office and came out with a light meter, I found out at that point my tint was to dark for that county in NM. And yes just that county! I received a ticket and a DOT write up for this, After hours of trying to remove the window tint that had been on the windows for ten years I gave up and had to replace the windows at a cost of $912.00 to satisfy the judge and the officer to dismiss the ticket.

November 08, 2012 10:06:40 AM

Great information, keep it coming, nice to know the gps info I will move it right away.Thanks

November 07, 2012 8:12:00 AM

Terry - I was very surprised when you checked our drivers side window of our Cascadia and how close we were to not being legal for window tint. It seems that any visible sign of tint is probably over the limit and could create a problem. After talking with you about the mounting of our GPS Bob made a bracket that is dash mounted, the GPS is still read easily and no more problems with the GPS illegally mounted to the windshield. Thanks for the tips on rock chips I will keep a nickel handy!

November 05, 2012 19:11:00 PM


November 05, 2012 17:14:57 PM