Why does stop-and-start driving consume more fuel than highway driving?
Stop-and-start driving uses 20-50% more fuel than highway driving. Engines work best at steady speeds. Constant stops and starts force hard acceleration, which guzzles gas.
Here's what you need to know:
- Engine efficiency peaks at 40-60 mph: Most car engines hit top fuel economy during steady highway cruising. Stop-and-go drops this by forcing inefficient low-speed operation.
- Acceleration burns extra fuel: Each time you speed up from a stop, your engine injects rich fuel mixtures. Braking wastes that energy as heat.
- Idling wastes gas too: Sitting at lights or in traffic burns 0.5-1 gallon per hour without moving forward.
According to AAA's 2026 cost of driving report, fuel makes up 18% of total ownership costs, or about $2,000 yearly for 15,000 miles. City drivers see higher bills because of poor mileage. "Stop-and-go traffic can cut fuel economy by up to 50% compared to highway driving," says the Sidekick Research Team, based on analysis of 1,200 verified owner logs (Source: Sidekick Fuel Data, 2026).
| Driving Type | Avg MPG (typical car) | Annual Fuel Cost (15k miles, $3.50/gal) |
|---|---|---|
| Highway | 30-40 mpg | $1,300 to $1,750 |
| Stop-and-Start | 15-25 mpg | $2,100 to $3,500 |
Data from EIA shows urban areas like Las Vegas (ZIP 89101) average 22 mpg vs. 35 mpg on highways. Fuel costs hit harder here with traffic congestion.
Practical tips to save fuel in traffic
- Accelerate gently: Ease onto the gas to avoid fuel spikes.
- Coast to stops: Lift off the pedal early to glide.
- Use cruise control on highways: Keeps steady speeds.
- Maintain tires: Underinflated tires cut mpg by 3-5%.
- Avoid idling: Turn off engine after 10 seconds at lights.
Sidekick tracks your real mpg patterns. Owners using our fuel optimizer report 12% savings in city driving, based on 850 users as of April 2026.
Highway driving lets engines sip fuel efficiently. City habits force waste. Track your routes with apps to mix more steady miles. Over five years, smart driving saves $3,000+ on fuel alone.