As of 31 March 2009, there were approximately 575,000 motorcycles registered in California with a model year of 2000 or newer. The ARB estimates that as of October of 2008 there were approximately 493,000 motorcycles that would be subject to the requirements of this bill. Since an inspection would occur every two years, SB 435 would integrate an additional 246,500 motorcycles into the smog check program each year.

Background. ARB estimates that motorcycles produce up to 15 times the emissions per mile as the average new car or light-duty truck. In December 1998, ARB adopted amendments to the California On-Road Motorcycle Regulations that added control of NO_x for Class 3 motorcycles to the original 1975 regulations for all motorcycles with engine displacements of at least 50 cubic centimeters (cc).

The original 1975 standards applied to hydrocarbons (HC), one of the two most important contributors to smog, and carbon monoxide (CO), a toxic air pollutant. The original HC standards ranged from 5.0 g/km to 14.0 g/km, depending on-engine size, and CO was set at 17.0 g/km.

In 1984, ARB amended these regulations to give manufacturers more flexibility to lower emissions. These new standards applied to 1988 model year and later bikes and could be met on a corporate average basis.

The amended regulations also split larger bikes (280cc and above) into two separate categories, 280cc to 699cc, and 700cc and over. The smaller engine group (280cc - 699cc) was required to meet a 1.0 g/km HC standard, while larger engines (700cc and above) were required to meet a 1.4 g/km HC standard. The CO standard for all bikes was set at 12.0 g/km.

The 1998 revisions set a Tier I standard of 1.4 grams per kilometer (g/km) HC+NO_x beginning with 2004 models and a Tier II standard of 0.8 g/km HC+NO_x beginning in 2008 for major manufacturers. The standards include corporate averaging provisions. For small volume manufacturers, the Tier I requirement begins with the 2008 model year, and there is no Tier II standard. Small volume manufacturers were defined in the final regulations as manufacturers with annual California sales of no more than 300 motorcycles.

A required 2006 review on manufacturers’ ability to meet the Tier I standard as well as an update on the progress being made toward meeting the Tier II standard found that all major manufacturers were able to meet the Tier I standard by the 2004 model year as required. On average, motorcycles sold in California by major manufacturers in 2004 achieved emissions of 0.92 g/km HC+NO_x, compared to the 2004 Tier I standard of 1.4 g/km HC+NO_x.

The 2006 review also found that on average, major manufacturer motorcycles certified for sale in California in 2006 achieved emissions of 0.87 g/km HC+NO_x—i.e., they were making progress toward meting the 2008 Tier II standard. Major manufacturers use fuel injection, oxidation catalysts, three-way catalysts, and/or various sensors to achieve this emission level. The ARB review found that three quarters of 2006 models used fuel injection, and two thirds used catalysts.

Tampering. However, ARB notes, tampering is a major concern for the on-road motorcycle fleet. According to industry surveys, one third of on-road motorcycles may be modified during or after purchase. Such modification may be considered tampering if the emission control systems are involved, and tampering may substantially increase emissions.

Tampering, according to ARB, would include removal of the catalytic converter or carbon canister, changing adjustable parameters or adding devices to boost horsepower. As more manufacturers include catalysts to reduce emissions (two thirds of Class 3 2006 model year motorcycles), this becomes a greater issue.

One way to address tampering is to require Smog Check for motorcycles. This is proposed in the 2007 State Implementation Plan (SIP). Once the tampering issue has been largely resolved through Smog Check and/or other means, current technologies provide an opportunity to further reduce exhaust and evaporative emissions from all motorcycles. Indeed, such reduction is a long-term measure that is also included in the draft 2007 SIP.

—2006 Review

The SIP had called for smog testing to be developed in the 2007/2008 timeframe, and to be implemented in 2010.

Resources

• 2006 Review of the 1998 Amendments to the California On-Road Motorcycle Regulations

• Motorcycle smog check proposed for California (LA Times, 3 May 2009)