Those who follow hybrid-electric automobile technology are well-aware that the Toyota "Synergy Drive" found in the Prius is considered more advanced than the Honda "Integrated Motor Assist" found in the Honda hybrids. Although the mileage figures are close, only the Synergy Drive can operate in motor-only mode, allowing the hybrid to run as an electric for short distances (this feature is what allows the aftermarket car hackers to turn the Prius into a fully gas-optional vehicle).
Expect to see GO-HEV hacks for the Hondas soon, as the carmaker announced today that its new hybrid engine for the 2006 Honda Civic Hybrid will allow for motor-only operation at low speeds. The improvements will also increase overall power while reducing weight and cost, and will allow for a moderate increase in fuel efficiency. The new Civic Hybrids should be out this Fall.
Who wants to lay odds on how fast the California Cars Initiative has a working gas-optional version of the 2006 HCH on the road?