proposed amendment to the motor vehicle safety regulations standards 121 206 223 and 301.2 7 pages available in english and french standard 223 rear impact guards as it relates to aerodynamic devices boat tails are devices installed on the rear of trailers that reduce aerodynamic drag thereby improving fuel economy. the current definition of rear extremity of trailers found in canada motor vehicle safety standard cmvss 223 imposes dimensional limits on material that extends beyond the rear of all trailers with rear impact guards. the department of transport proposes to modify the requirements of cmvss 223 rear impact guards by modifying the definition of rear extremity to allow for a wider variety of aerodynamic devices. this definition will create a zone behind the trailer where boat tails would be permitted. expiration dates for standards 121 air brake systems 206 doorlocks and door retention components and 301.2 cng fuel system integrity certain requirements of the motor vehicle safety regulations the regulations have expired including the antilock brake systems abs external malfunction indicator on air-braked trailers as referenced in subsection 121 4 air brake systems section 206 door locks and door retention components and certain alternative test procedures referenced in section 301.2 cng fuel system integrity of schedule iv of the regulations. these expired requirements are still relevant and need to be reinstated. this proposed amendment would reinstate the requirement that trailers with air brake systems abs be equipped with an external abs malfunction indicator lamp. this change would improve safety on canadian roads and hel inspectors to identify these malfunctions. it would also have the benefit of re-establishing harmonization with the united states safety standard on the subject of air brake systems thereby relieving manufacturers of any unnecessary burden resulting from disharmonized manufacturing requirements. the proposed amendment would revise the expiration date of section 206 door locks and door retention components of schedule iv of the regulations to january 1 2017 as well as remove several requirements that will have expired by the time these regulations come into effect. section 301.2 cng fuel system integrity of schedule iv of the regulations serves to reduce deaths and injuries occurring from fires that result from fuel leakage during and after motor vehicle crashes. this section makes reference to alternative test procedures that are no longer applicable as they have passed their expiration date of february 28 2009 but still provide relevant and suitable alternatives. the proposed amendment would have the expiration date revised and reinstate the alternative procedures. this would provide manufacturers with testing alternatives that could reduce costs associated with the certification of vehicles to the respective safety standards.