Can you use ECO on the highway or is it for city only

Use it whenever you want to save fuel, which at today’s prices should be all the time.

Active Eco, engaged by a dashboard switch to the left of the steering wheel, modifies engine operation so you get more gradual acceleration, and the transmission tends to shift to higher gears sooner and isn’t as quick to downshift for passing. Active Eco also cuts off the fuel supply during deceleration, and Hyundai says all this electronic management can increase fuel economy as much as 7 percent.

All the hyundai elantra 2013 has the ECO?