HERRIMAN, Utah – Gas prices have edged down from their record highs, but they are still a far cry from being affordable for many Utah families.

So, when Google rolled out a new feature for its Google Maps navigation app and claimed it could save you money on gas by using suggested eco-friendly routes, the KSL Investigators decided to put it to the test.

The app calculates multiple routes based on distance, speed, and now fuel efficiency. In some cases, the fastest route is also the most fuel-efficient.

For our test, KSL Investigates producer Sloan Schrage and Matt Gephardt settled on a trip from Herriman to Salt Lake’s Central City neighborhood, a distance of nearly 26 miles.

Google Maps gave us three options for our mano-a-mano race. We were only interested in two: the fastest and the eco-friendly alternative, indicated by a leaf symbol, which Google says will burn less gas and save more money.

Google indicated the eco-route would be three minutes slower but would burn 6% less fuel.

With the two routes mapped out, Matt gassed up his minivan and Sloan filled up his compact SUV and we set off, both sticking to posted speed limits.

The faster route is down the speedy, 70 mph Interstate 15, while the eco-friendly route took Sloan down the slower, mostly 60 mph Bangerter Highway.

So, how did the app come up with that route?

Google said the artificial intelligence goes into the math, along with data from the National Renewable Energy Laboratory. There are other factors: current traffic levels, distance, elevations, streets versus highways, and stoplights. These factors cause drivers to slow down and then speed up repeatedly, which the EPA says burns up a lot more gas: up to 30% more gas on the highway and up to 40% more in stop-and-go traffic.

Digging deeper into Google’s number-crunching factors, we found the eco-route has 26 stoplights compared to the faster route’s 17 lights. But speed limits are a big factor because just slowing down from 70 to 60 miles per hour will save you around 14 percent in fuel consumption, according to the U-S Energy Department.

By taking the eco-route, Sloan arrived at our destination 6 minutes and 20 seconds behind me – more than double the estimated three minutes. But did he save on gas?

We filled up our tanks again to record how much gas we burned – 1.649 gallons in Matt’s minivan and 0.879 gallons in Sloan’s compact SUV.

Then we headed back to Herriman, fueled up at the same pumps for another drive downtown. This time Matt drove the eco-route while Sloan took the fastest.

This time around, the eco-route added nine minutes and two seconds to Matt’s drive time, more than three times Google’s guestimate. To find out how much money, if any, the greener route saved, we filled our tanks for the final time using the same pumps. This time, Matt’s minivan burned 1.173 gallons, while Sloan’s compact SUV burned 0.98 gallons on the faster route.

Here’s the math: the eco-route saved Matt 0.476 gallons. His total savings equaled $4.99 a gallon, which we paid per gallon of regular gas that day; his total savings equaled $2.38.

For Sloan, the savings were less: 0.101 gallons multiplied by $4.99, equaling to 50 cents.

Either way, Google’s eco-routes turned out to be a win for inflation-busting. It did save us both money at the expense of added drive time.

Google said in cases where the fuel savings are too small, or the eco-route significantly adds drive time, Google Maps shows its calculated fuel savings to help you compare before you drive.