Required Change	Environmental Reason	Automotive Related Results
Reduction of Lead Use 1/1/85 1.1 gram avg. per gal. 7/1/85 0.5 gram avg. per gal. 1/1/86 0.1 gram avg per gal. 1/1/95 No lead or heavy metals	To reduce health hazards via reduction in airborne lead	Fuel volatility is increased resulting in increas of hot-start/hot-driveability problems.
Regional Oxygenated-Fuel Program 1988	To reduce CO emissions	Increased use of ethanol and MTBE. No major automotive problems experienced.
EPA Phase I Volatility Controls 1989	To reduce evaporative emissions and ozone formation	Reduced vapor pressure of fuel results in dramatically reduced hot-start/hot-driveability problems.
EPA Phase II Volatility Controls 1992	Further reduction in evaporative emissions and ozone formation	Further reduction in vapor pressure should nearly eliminate all hot-start/hot-driveability problems. Some older vehicles may ezperience cold-start and warm-up performance problems on unseasonably cool days.
Oxygenated-Fuel Programs 1992 (All CO non-attainment areas)	To reduce CO emissions	Expanded use of ethanol, MTBE, and possibly other oxygenates. No major problems anticipated based on success of existing programs.
Reformulated Gasoline 1995	To reduce ozone formation and air toxins	Further expanded use of fuel oxygenates. Some alteration of fuel properties. Performance standards expected to be similiar to existing gasoline.
Deposit-Control Additives 1995	To reduce exhaust emissions	Reduced CO and hydrocarbon emissions, improved warm-up performance due to lower intake-valve deposits.

Charts and tables for this article are taken from Changes in Gasoline II Technician's Manual, Downstream Alternatives Inc., 1995.