Questions about Cab Lights, Broken Brake Chambers, Tire Pressure
& More Answered by Law Enforcement Officials (as of July 2011)
Warning: Laws are subject to change without notice.
These interpretations were made on June 11, 2011.
Brought to you as a public service by Ol’ Blue, USA and 10-4.
Submit your questions to www.askthelaw.org
SOME TRUCK SHOW UPDATES
We would like to thank everyone who came by and asked questions at the Great West Truck Show in Las Vegas. Our next stop is at the Great American Trucking Show, held August 25-27 in Dallas, Texas. Ol’ Blue, USA’s “Ask The Law”™ team will be in our Safety Center™ along with troopers from the Texas Highway Patrol to help drivers and fleets understand various laws. Visit www.safetytour.org for details.
CAB LIGHTS IN CALIFORNIA
Q: Lately I have been noticing that a lot of truckers have removed all of the lights from atop their cab. It has always been my understanding that the federal regulations require a minimum amount of marker lamps on the cab. Is this not true? Thanks – Mike in California
A: Provided by Officer Amy Bachelor, California Highway Patrol, Commercial Vehicle Section, Sacramento, California: The lights on the top of a cab are categorized by two types of lights. The two outside lights are clearance lights and the three lights in the center are identification (ID) lights. Federal law requires both clearance lights and ID lights on commercial motor vehicles. California Vehicle Code Section 25100 requires clearance lights and Section 25351 permits ID lights. A California-only truck may have the ID lights removed, but must display clearance lights on each side, mounted on a forward-facing portion of the vehicle, and visible from the front.
DEFECTIVE BRAKE CHAMBER
Q: My 48’ trailer’s brake chamber is not leaking, but the inner spring is broken. The mechanic said that if it isn’t leaking, the chamber is okay, but I think it will not work properly when the trailer is loaded. Would it be a DOT violation if I used this trailer with the defective brake chamber? Thank you – Andy in Indiana.
A: Provided by Jim Brokaw, formerly a Staff Sergeant with Nebraska State Patrol, Carrier Enforcement Division, Lincoln, Nebraska: Yes – broken brake system components are safety violations. The mechanic is mistaken in considering the brake chamber to be okay. 49 CFR 393.48 requires brakes to be operative and 49 CFR 396.3(a)(1) requires parts and accessories to be in safe and proper operating condition at all times. Also, the North American Standard Out-of-Service Criteria specifically lists a broken brake chamber return spring as one of the conditions that would determine that a vehicle should be put out-of-service.
PERFORMING AN AIR LOSS TEST
Q: I understand there is a one-minute air test done by the DOT on a 5-axle CMV. What is the maximum air loss allowed? How can a driver check this air loss like the DOT does? Thanks – Paul in Minnesota.
A: Provided by Sgt. Pete Camm (Ret.), California Highway Patrol, Sacramento, California: Manufacturing standards for air brakes are found in Title 49 CFR, 571.121 – obviously they are not supposed to leak. There are two one-minute tests conducted, both with the engine off (the ignition can be off or on). The first test is completed with all brakes released. The allowable air loss for a two vehicle combo is equal to or less than 3 PSI per minute. The second test is conducted with full service brake application (air pressure should be between 90 and 100 PSI at start of test). An air loss of more than 4 PSI per minute is a violation. Air brake tests should be outlined in every state’s commercial driver’s handbook, since pre-trip inspections are part of a “drive test” as required by 49 CFR, 383. You can also search “Air Brake for Phoenix Fire Department” via Google to watch a video.
RULES REGARDING TIRE PRESSURE
Q: What are the rules for tire pressure? Some DOT officers say low pressure is a flat. Is there a legal range? Thanks – Paul in Delaware
A: Provided by Senior Trooper Monty Dial (Ret.), Texas Highway Patrol, Commercial Vehicle Enforcement Division, Garland, Texas: In Part 393.75(h)(2) is an explanation on what is considered an under-inflated tire. Also, in the CVSA Out-of-Service Criteria, it states that if a tire has 50% or less of the max inflation pressure marked on the sidewall that the vehicle should be placed Out-of-Service.
~ The Ask The Law™ programs are an ongoing educational effort between Ol’ Blue, USA™ and commercial law enforcement agencies. Ol’ Blue, USA is a non-profit organization dedicated to highway safety education and to improving relations between the motoring public, law enforcement and commercial drivers. “Ask The Law” is a registered trademark of Ol’ Blue, USA. This column is copyrighted© by Ol’ Blue, USA. Warning: Laws are subject to change without notice. These interpretations were made on June 11, 2011.
