In the end, the most important question about any high-tech "green" car is what it achieves with all its technology.

Performance

For the second generation model (the version for the U.S. and other world markets), Toyota has tuned the Prius to improve performance over the original Japanese version. Car & Driver reported a 0-60 time for the Prius of 13.0s, compared to 10.6s for the Insight.

Energy Efficiency

According to 2000 EPA estimates, the Insight achieves fuel efficiency of 61 mpg city / 70 mpg highway. Actual owners' fuel efficiency statistics have shown the EPA estimates to be quite accurate. The Prius achieves fuel efficiency of 52 mpg city / 45 mpg highway.

While the Insight achieves better efficiency than the Prius in both city and highway driving conditions, the Prius is unique in that its city efficiency is better than its highway efficiency. This is a direct result of the Prius being designed for tight urban driving conditions, such as is encountered in Tokyo.

Carbon Dioxide Emissions

A direct result of the better fuel efficiency is that the Insight also achieves lower "greenhouse gas" (carbon dioxide) emissions than the Prius. The EPA estimates annual greenhouse gas emssions from the Prius at 4.0 tons, while it estimates annual emissions from the Insight at 3.1 tons.

Measured Against Most Stringent California Emissions Standards

Greenhouse gas emissions are not measured by California's emissions standards. California's standards are only concerned with emissions that lead to smog in cities: Hydrocarbons (HC), Carbon Monoxide (CO) and Nitrogen Oxides (NOx). While these are definitely important, it is important that consumers like you and I let manufacturers know that we also recognize the importance of greenhouse gas emissions (CO₂). Fortunately we are seeing this begin to happen; when a major American manufacturer produced an ad showing one of their SUVs in a green forest with text proclaiming it to be a certified Low Emissions Vehicle (LEV), public outcry forced them to withdraw the ad. While it may have been LEV certified, its high fuel consumption and corresponding high carbon dioxide emissions hardly made it an environmentally responsible vehicle.

The 5-speed California's Ultra-Low Emissions Vehicle (ULEV) standard, while the CVT automatic Insight meets the Super-Ultra-Low Emissions Vehicle (SULEV) standard. The Prius (CVT automatic) also meets the SULEV standard.

Both Cars Recognized for Clean Operation

It was the combination of ULEV levels and low carbon dioxide emissions that led the Sierra Club to give their first ever product award to the original 2000 Insight. Subsequently, the Sierra Club has also issued an award to the Prius, calling it as the "first green family car" - a reference to the Prius' five-seat capacity.

The Toyota Prius