(maybe this should be in IMHO)
I want to do more to help the environment. One of the ways I thought to do this was to start driving 5 miles under the speed limit. I live on a rural divided highway on the outside of town. From my house to town the speed limit is 45mph most of the way. Most of my driving in town is on two lane one way streets with a speed limit between 25 and 35 mph.
I like driving 5 miles below the speed limit because it is more relaxing, I feel like I am not in a hurry to get anywhere when I drive at that speed. However, people ride behind me and pass me when I drive 5mph below the speed limit. I have a mild anxiety condition and that makes me nervous, having people behind me and passing me. Conversely, I like most people don’t like to ride behind someone else driving slow. I think I will keep driving the speed limit but if there is a compelling need to drive 5mph below the speed limit for the sake of the environment I would consider giving it a try. This is just one of a handful of areas where I would like to make efforts to help the environment.
Added note: I suppose when I drive 5mph below the speed limit I am actually driving between 10 and 15 mph slower than I normally would. Normally I drive 5 mph above, sometimes 10 (I try to bring it back down when I hit 10 mph above). So really, by driving 5mph below the speed limit I am probably driving 12mph slower than I would otherwise.
The two things you have mentioned here don’t necessarily connect; there will be a speed at which your car is optimally fuel efficient in high gear - if you drive slower or faster than that, you sacrifice fuel efficiency a little or a lot.
In the UK, you can fail your driving test for going slower than the speed limit when there is no reason to do so.
The proliferation of speed cameras has pretty much stopped people speeding in town, although not on motorways.
In general, the safest speed and the most relaxing speed, is to keep up with the other traffic so long as that is not breaking the law, or at least, not excessively.
I determined by driving my car over the same stretch of road at varying speeds it got it’s best fuel mileage around 40 mph. This is going to vary somewhat depending on the car though.
If you want to contribute to the environment, simply decide not to reproduce.
The benefit to the Earth from all your offspring never existing will far exceed the benefit from anything else you can do. In fact as a childless person you can be insanely Biff Tannen-level environmentally profligate and still come out ahead of a hard-core greenie with a couple kids.
Considering your other threads of ecological matters, the other big thing you can do to reduce your footprint is to move to a city. Living out in the sticks is very, very environmentally wasteful. Nothing else you could change can offset the incremental harm of living out there.
I’m going to defend driving 5 below the limit… As long as it is done courteously. Stay in the slow lane. If you’re on a longer stretch of road and people can’t pass, pull over. If you plan on it taking longer to get somewhere, you’ll rarely be late. If driving a little slower is part of a comprehensive “I’m going to do things that bring me enjoyment while not forgetting I’m part of a community” type of outlook, I say go for it.
I would encourage you to find out more ways to have our society and the environment work better together. What you propose seems to be against both. You cause people to consume more fuel to pass you, for very little mpg gain on your part, and you get society to see you as not helpful to either.
More for your posting I am picking up that you don’t want to drive that fast and perhaps would rather have a place where you won’t have to drive. Perhaps you should consider moving to a place like NYC. That would be more of a societal and environmental thing to do then cause a traffic slowdown and high speed passing whenever you want to travel.
I believe if you are actually slowing down traffic and causing high speed passing you are harming the environment far more then your lower speed helps it.
If you are driving at 5 below the limit at 40, it’s actually closer to 8 below the limit.
All modern speedometers are calibrated to over-read the speed by several percent. So an indicated 55 is probably closer to 50 actual.
In terms of driving, I really don’t like driving at max speed. Where I am, open roads are 110 km/h ~ 70 mph. I prefer to go max 100 km.h whereas most other drivers are at or above the nominal speed so there is often traffic behind me.
Ditto for slower speed sections. driving under the limit is less stressful and infinitely safer given the cvaiety of animals that jump out at you.