Which of the following is NOT a recommended strategy to reduce vehicle emissions in cities?

• A. Subsidizing gasoline-powered vehicles.
• B. Expanding parking facilities in city centers.
• C. Building more roads and parking to accommodate more cars.
• D. Doubling speed limits on major corridors.

Answer: (D)

Increasing speed limits in cities is not a strategy that lowers vehicle emissions. Higher speeds raise fuel consumption per mile because aerodynamic drag grows with speed, and urban driving often involves acceleration, braking, and idling that waste fuel regardless of posted limits. Pushing speeds up can also worsen congestion and crash risk, which can lead to more overall emissions rather than fewer.

In contrast, policies that actually reduce driving or improve vehicle efficiency tend to cut emissions. Subsidizing gasoline-powered vehicles tends to increase the number of cars and total miles driven, pushing emissions up. Expanding parking in city centers makes driving more convenient and attractive, encouraging more trips. Building more roads and parking to accommodate additional cars similarly increases vehicle miles traveled and pollution.