Max MPG vs annoying other drivers
 

I have a non hybrid Honda Civic that has about 50k miles. Here is what I learned.

I can get up to 56 mpg going with the normal wind direction with about a 74 ft elevation drop from my driveway to work of about 48 miles. I have found that I need to be in Eco mode, I use enough gas to only have to moderately brake at an intersection, light acceleration and running 55mph on the highway, the temp needs to be above I think 50 degrees, not sure about humidity yet and I basically sit in the slow lane the whole way on cruise control. Going home the best has been about 46 mpg. I always use the base gas of 87. The quality of that gas also has a significant effect, say a max drop of about 6mpg.

The problem is that the speed limit is 70. If I go that fast, then mpg is about 42 with limited speed changes. At 55 mph, large trucks tend to run up close to me and are clearly annoyed. What are your thoughts on whether to drive slow or fast? My thoughts are that as long as they have a way to pass me and traffic is not too thick, then I will go slow.

Mike
Springfield, Ohio, USA

I think 56 mph is the standard UK lorry speed, for maximum economy and flow of motorway traffic. I sit in the slow lane at 56 mph, and most lorries dont get bothered by it, or bother me. Could you just cruise that 1 mph faster if a lorry gets uncomfortably close? I've heard that in the UK travelling just a bit under 56 means you can get pulled on the motorway for causing an obstruction (happened to someone i know once).
Better too slow than too fast - this week alone saw two near fatalities from no brain selfish pr#@ks overtaking needlessly against oncoming traffic.

Hello,

Correct me if I'm wrong but isn't there a lane just for slow vehicles on US highways? If there is, you could try using that lane and let the cruise control do its job. My mother has a Volvo S60 T5 2.4L and at 55 mph it gets 40+ MPG just by using the cruise control.

Hi, Im also in central Ohio.

In my opinion, if you are on a major freeway, you should stay in the right lane within say 5 mph of the speed limit (ie 65 in a 70) or you may be causing safety issues for others.

If you are fixated on high fuel efficiency only, consider taking a different route that allows for slower speeds. If you are after saving on fuel and mileage costs - find a route that is shortest to/from your destination.

I have kept track of fuel economy on a few routes of my daily drive. For me, the key factors have been: # of stoplights, outside temp and head/tail wind speeds. I drive at the speed limit.

Good luck.

Speed limit (well, in the UK) is a maximum, not required speed. Lots of roads are dangerous if driven at the posted limit. Safety must come before not annoying faster drivers. On single lane A roads, the limit is 60mph and i try to maintain 56. On my rural hilly, twisty, narrow and pot holed route to work 35-45 might be the fastest safe speed. If someone gets up close behind (rare), they can steady on or overtake if possible. The closer they get, the slower i go to maintain a safe stopping distance if i have to brake for a tractor or deer. Dual carriageways and motorways are 70mph limit, but i stick at 56mph with the lorries, there are 1 or 2 lanes to pass me by!

In the UK its not a slow, medium and fast lane - the rule is drive on the left unless overtaking. In reality i suppose it does work out slow, medium and fast, lots of middle lane hogs!

If it is a multi lane highway, just stay in the right lane. If you're 20 MPH or slower than the speed limit many states require you to turn on the hazard flashers. Stay to the right of your lane , not the center - its called "Ridge Riding". cars coming up on you from behind notice your lane position, which gets their attention, then they notice you're slower than they are. You just need to keep a close eye on the rear view mirror. If someone is still coming up on you quickly, you may need to turn on your hazards.

No offense Jay, but if you have to put your hazards lights on while on a freeway to drive well below the posted limit, then I think you ARE a hazard.

Don't get me wrong, drivers blowing by at 20mph over the speed limit are hazards too.

That was his point. Putting your hazard lights on alerts other driver's that you're driving dangerously slow compared to everyone around you.

I cant imagine EVER justifying driving 20 below the speed limit. If you're going that slow, you might as well stay on the access roads. But then you hit every light in the world, so you're not going to get great fuel economy that route either.

I can imagine there's no problem driving as fast or as slow as you like in the US, plenty of lanes to do as you wish. What annoys us in the UK is people doing 35 to 40 MPH on our single carriageway roads. People get so annoyed and end up overtaking in silly places into oncoming traffic etc, probably one of the main causes of accidents here.