Yah, this can make an overwhelming difference in the long run. I used to drive semi-regularly between Wisconsin and Minnesota, a stretch of about 280 miles; others in my family would make the same trip with the same car during the same times of year, and my mileage per tank was always significantly different, and we couldn't figure out why initially.

Turns out they used cruise control for most of the stretch, which I never used, and it was often the difference of 3-5 gallons over the course of the trip. Not a huge deal, but $4 gas did influence it a bit.

For clarity, did cruise control produce better or worse mpg figures?

Ah, yeah, I see how what I wrote was not clear.

Cruise control was significantly worse than driving it normally, at least when I was at the wheel.

The route is a very hilly one, so I somewhat suspect it's that the cruise control was not very good at knowing when to accelerate and when to coast.

It's definitely that.

My 2007 Civic doesn't account for incline when doing cruise control. It has some sort of lookup table that says, "When the owner sets me to 65 miles per hour, I go at this RPM." If I keep slowing down because I'm on a hill, it downshifts a gear and accelerates hard until the car goes back up to 65 miles per hour. Wash, rinse, repeat. I always disabled cruise control on hills because of it.

My fiancee's 2014 Nissan Rogue accounts for hills with cruise control, and it never has these intervals.

I find that the cruise control on a 2015 Hyundai (automatic transmission) always gets better mileage than I can without, even on hilly trips. (Where I live all trips are hilly.) I do help it out by shifting to neutral when on long downhill stretches.

So many people hate you if you do that. They will pass you angry, just to stop 5m down the road while you get there behind.

Driving well below allowed speed limit is dangerous, especially in high speed and high traffic roads, because a car behind you might be forced to brake, the car behind it brakes harder, next one even more harder creating a chain reaction that might end up in collision when the last driver doesn't have enough time to stop. There's reason why "minimal speed" sign and rule exists.

Sure, but we're talking about city driving near a red light, not breaking flow on high speed roads.

My mother needs to learn this lesson. Light turns green? Stomp on the gas. Light turns red? Stomp on the brakes.

She drives a minivan with a V8 and uses every bit of it on winding Massachusetts roads. People who haven't grown up with it get carsick.

She's a damn good driver - in 10 years, she racked up about 430,000 miles in a Toyota Sienna without an accident... but holy fuck she's traumatizing to ride with.

She'd love a Dodge Grand Caravan we have them for work service vehicles and I was amazed at how quick it shifts.

At first I thought it was a mistake almost like the engine was lugging but it was in eco mode and shifting early.

In normal mode it can shift through three or four gears in (what felt like) one second. And it has a seven speed transmission.

I was wondering if I got a Hellcat trans by mistake!

My grandparents have a chrysler 200 with an 8 speed automatic and I hate it. It spends it's entire life searching for the perfect gear because the computer has too many to choose from.

When you're on the highway in cruise I'm sure it selects a ratio that gets the best possible milage, but they live in the country. You need to accelerate through tight turns, pass slower vehicles without hitting oncoming traffic and constantly adjust the throttle and steering on dirt roads based on conditions. Driving in the middle of nowhere is a very active process and it always feels like that car is just in the way.

Just a tiny bit of throttle causes it to downshift 2 or 3 times and rev the nuts out of the engine when all I wanted was just a little more torque. Lifting off just a little to prepare for a tight bend upshifts to engine brake, so once you're halfway through the corner and want power to accelerate through now it has to downshift 3 or 4 times to get the revs back up. It feels like I am constantly at war with the transmission trying to get it into the right gear and then stay there. It's the most indecisive codriver I've ever experienced.

Does it have an eco mode engaged? That's what the Dodge van does when the green eco button is on but not the aggressive downshifting.

One other thing about the van it's so sluggish off a dead stop it's as if a normal press of the throttle does nothing a tiny bit more you're spinning the wheels and massive torque steer.

What production minivan has a V8? I can't even think of one looking back to the 1980s.

I've ridden with people that drive like that. Self-driving cars can't come soon enough.

Toyota Sienna. Before that, it was a Chrysler Town & Country, which she went through four transmissions on before finally giving up on it. Looking it up, I guess it was a V6, but it had some serious power on it.

I just found it funny that brake jobs on that poor minivan always cost shitloads of money because she always ground the pads all the way down to the metal and obliterated the rotors. I'm sure that the mechanic always sighed and shook his head ruefully at her.

When I took my fiancee home to meet the folks, she made her carsick. I found this hilarious because I'd grown up with it, so it was completely normal for car rides to be ZOOM-STOP-ZOOM-STOP the whole way.

For the record, I drive like a grandma.