I’m not sure, but I’m currently conducting an experiment to find out. Using cruise control on NJ highways is tricky, especially during rush hour-types of traffic. Monday and today I’ve done it fairly successfully on Route 21 and Route 80 going to work, but it’s pretty much useless on the way home, unless Route 21 is empty.
The idea is that by keeping your speed and RPMs fairly constant, it increases gas mileage. According to Edmunds.com, you’ll reap up to 14 percent savings at the pump. TThe web site’s experts conducted a bunch of tests to separate the facts from the myths when it comes to decreasing gasoline consumption:
Test #3 Use Cruise Control
Using cruise control is a bit of gas-saving advice frequently on tips lists. We have always agreed with this tip in theory but we hadn’t expected such significant results. First, it smoothes out the driver’s accelerator input by preventing nervous “surging.” Second, it makes the driver take the long view of the road rather than reacting to every change in the traffic around them.
Method: We did this test twice with four different cars each time driving the 55-mile loop. The first time we set cruise control to 70 mph. The second time, with the cruise control off, we varied our speed between 65 mph and 75 mph. We tried to mimic the driving style of a person who is in moderate freeway traffic.
One thing that’s important to note: if you are in a mountainous area you should turn off cruise. It will try to keep you up to the speed you’ve set and will use a lot of extra gas downshifting to lower gears to accomplish this.
Apparently, using cruise control in hilly regions (such as Route 280) isn’t going to help. And they used higher speeds (70-75) than the NJ speed limit, so I think it’s safe to assume the savings are even more substantial at lower speeds, such as 55-65. I set my cruise at 61-62 when I can, so I’ll determine if it’s worth the effort once I see how many miles I get out of my current tank.
Also, the Edmunds.com article shows the results from other driving tests, such as slower speeds, less-aggressive driving.