PSI Remarks: EPA GHG-2 Proposed Rulemaking 

August 6, 2015 

Good afternoon. My name is AI Cohn, Director of New Market Development and 

Engineering Support for Pressure Systems International, better known as PSI, 

which is the global innovator behind automatic tire inflation systems (A TIS). 

My interest in presenting at this hearing is to address the definition of an 

automatic tire inflation system and the requirements of a 'qualified' A TIS system. 

Our company invented our automatic tire inflation system 22 years ago and 

market it globally. In N.A. {North America) we market it under the Meritor brand 

name- t he Meritor Tire Inflation System by PSI. 

Commercial trai ler tires receive t he least amount of maintenance on commercial 

tractor/trailer combinations. Today, we estimate that approximately half of the 

commercial trailers being produced in N.A. have some type of tire solution, with 

the overwhelming majority being A TIS. We also estimate that over 1 million 

trailers are currently running with A TIS today. The benefits of A TIS include 

increasing fuel economy, reducing greenhouse gas emissions, & significantly 

reducing tire & safety related roadside service calls. It also dramatically reduces 

road debris from tire casings, and better utilization of casings for retreads for 

lower oil consumption by the tire manufacturers. A typical return on investment 

is well under 12 months. 

The basic principal of A TIS is to insure that tires maintain a minimum specified tire 

pressure as determined by the fleet. However, there are numerous 'tire 

solutions' in the market today, and there are operational characteristics between 

some of those that classify themselves under the A TIS heading. With most A TIS 

systems air is automatically added whenever an individual tire pressure drops 

below the system sett ing, either whi le t he trailer is in a static or dynamic state. 

I wish to clarify two (2) important items in the proposed ru lemaking. The 

definition of automatic t ire inflation listed in Subpart 1, Definitions & Other 

Reference Information, is not consistent with t he historical industry definitions. 
TMC, The Technology Maintenance Council, of the American Trucking Association, 

in their Recommended Practice, RP239A (most recently updated in 2014) uses the 

following widely accepted definition of A TIS: 

Automatic Tire Inflation Systems maintain tire pressure at a single preset 

level and are pneumatically or electronically activated. A warning lamp indicates 

to the driver that the system has been activated and air is being added to a tire. 

These systems eliminate the need to manually inflate tires. 

The current definition included in the rulemaking states: A TIS means a system 

installed on a vehicle to keep each tire inflated to within 10% of the target value 

with no operator input. 

Assigning an arbitrary number of 10% is not consistent with the laws of tire 

physics. Tire pressure increases by 15- 20% when the tire is hot and running on a 

fully loaded vehicle at 75 mph on asphalt roads on a sunny day. Tires cool back 

down to the specified tire pressure after a few hours. 

The issue with tires and reduced fuel economy & increased greenhouse gas 

emissions is because of tire underinflation. A TIS systems assure that tires will 

always be running at the recommended cold tire inflation pressure. 

The second issue to address is a clarification regarding "qualified" automatic tire 

inflation systems. Page 1026, §Section 1037.107 Emission standards for trailers of the 

proposed rulemaking, discusses the use of low rolling resistance tires and that 

"qualified" automatic tire inflation systems are required on non-box trailers 

effective MY 2018. It is our recommendation that the term "qualified" be 

expanded. SAE Recommended Practice J2848-2, dated June 2011, is an RP on the 

subject of A TIS. It is the industry standard that details the basic operational 

requirements for any A TIS. This RP should be referenced in the proposed 

rulemaking when "qualified" automatic tire inflation systems are discussed. 

Thank you very much for allowing me to address this group and will be happy to 

entertain any questions or comments. 

(2 Attachments: TMC RP239A and SAE J2848-2)