A while back my brother and I were driving somewhere. I noticed that he kept glancing at the speedometer, and eventually asked why. He said, “You don’t look at the speedometer much.” I agreed that this was true. Sounding puzzled, he said “but you’re maintaining a constant speed. I mean, I look like every twenty seconds, and you’re looking once a minute or two.” I replied that I could feel how fast I was going, so I didn’t need to look very often. And… he seemed to think that was impossible.
At first I thought that maybe he can’t tell how fast he’s going because he’s had seven years less practice driving, but now I’m wondering if this actually is strange. I’ve never heard anyone else mention it, so…
Can you feel a difference in speeds? Thirty feels different from thirty-five and so on. I can usually feel the change if I’ve accelerated or decelerated by more than 5mph, and glancing at the speedometer always confirms the feeling. It’s harder to pinpoint above 50mph, and for reasons I can’t fathom, listening to an audiobook instead of music makes it harder too. I don’t think it’s the engine noise, since not only do I always have the radio up loud, I’ve always been able to do this, no matter what I’ve driven, including cars I’ve borrowed for the day. Something definitely feels different at various speeds, though I’m not sure what it is, exactly.
So, what about it? If it does seem strange, then it’s probably something to chalk up to an inner-ear thing since I know there are abnormalities in there.
Once I’m up to cruising speed on any particular road, I can usually hold that speed pretty well or notice if I’m speeding up or slowing down. My car is a manual transmission, though, so I have to pay attention to the tachometer and shift points, and I know what speeds I’ll be at in certain gears. There are times (and it seems to be on certain roads around here) where I’ll start from a stop sign or a light, come up to speed with the other traffic, and then notice that we’re all about 10 or 15 miles per hour over the limit. In general, once I’m acclimated, I hardly look at the speedometer at all.
However.
It’s possible to acclimate to very different speeds. I was in Germany a couple years ago and drove on the Autobahn for the first time. When I first started out, I was hyper-alert, paying attention to everything (much more than on a freeway in the States). When I got to one of the no-limit sections, I started speeding up, until I got to 100 miles-per-hour. Now I’m just totally wired, but I’m also thinking “I’m doing 100 on the Autobahn; this is so cool!” 20 minutes later I’m looking at the slowpokes in front of me thinking “you’re only doing 100, what’s the hold up?” That was the weirdest thing about it; you get used to it.
First, you certainly can definitely develop a feel for how your car feels at certain speeds and naturally, certain people are better at this then others. Also, there are of course visual cues you can use though they become increasingly less useful the faster you go. Finally, there is the ‘sense’ of speed. Note though, that what you’re using to judge speed is largely your car, and not so much an actual ‘speed sense’ unless you’re doing a lot of stops and starts.
The reason for this is the mechanism [other then visuals which is of course a big one] the body uses to detect speed; the inner ear. This is the same system you use to determine what side is up, whether you’re leaning etc.
It’s much easier to describe with pictures but I’ll do my best. Basically, you have a couple of sets of little chamber of liquid with tiny hairs standing up in the middle of that liquid. That’s your default state, little hairs just doing nothing which is interpreted by your body as ‘just chilling.’ Now, when you speed up that liquid sloshes back, thus moving the hairs and telling your body that you’re accelerating. However, if you maintain that speed those tiny hairs are slowly going to shift back to their ‘default’ position.
The best example I can think of is flying [which is oddly enough the area where this phenomenon causes the most problems]. When you take off there’s an initial feeling of speed. But, after a little time that sensation is gone and you might as well be flying at 55mph as well as 555 for all your body can tell.
This is especially a big deal when pilots are flying without visual cues. They can be in a far steeper bank than they realize and not feel it until they go crashing down [which is why instruments are so important].
Anyway, looking back it’s a bit of a clumsy definition but I’m sure someone can come along later to explain it better.
This sounds like BS but I assure you it is true. Many years ago I read a court report in Canberra about a guy fighting a speeding charge. In those days I think they had no radar and usually a patrol car had to follow you for 3/10 of a mile to record your speed. This guy insisted he was in some kind of club(?) in which the members practiced estimating the speed they were travelling at and checking it with stopwatchs. He said that he could estimate his speed more accurately than a car speeedometer and then went on to explain all sorts of factors that could effect the polkice vehicle’s speedo. I think he got off.
I had always remembered the story, not for the infomation about speed estimating but for what I figured had to be the most pathetic “club” on earth. What would a meeting consist of?
I’m pretty good with estimating the speed a vehicle is traveling without looking at the speedometer. I can usually tell within 5 mph how fast a car I am either driving or riding in is traveling. Just for practice sometimes I will guess the speed and then look at the speedometer just to see how close I am. One time I was driving my mom and dad’s pickup truck. It had an electronic speedometer readout. That day the entire dashboard display went blank on me, so I had no idea how fast I was going (Would the cop have let me off on this were I pulled over and I told him I really had no idea how fast I was going?) Between my own perception of the speed of my driving and by following the speed of the traffic flow I managed to make it home without overestimating my speed and getting pulled over.
Probably not. A couple of years ago I had a 1983 Renault. (It used to be my grandmother’s, I was without a car and she decided she was too old to drive so she gave it to me). The car did not handle the transition from a twice-a-month pootle to the shops with a 75-year-old behind the wheel to frequent 90-mile long round-trips to my girlfriend’s house well, and bits kept breaking. Among the first to go was the speedometer, but I never had a problem - I just drove with the traffic. I never got it repaired, as it would have cost more than the car was worth. The water pump blew and destroyed the engine a few months later.
My current car has a digital speedo, and I often find, when I glance down at it, that I am doing EXACTLY 50 in a 50mph zone, or within 2mph either side. In 30 zones I usually find I am doing about 34 as that is a comfortable RPM in third gear, so I have to make a conscious effort to slow it down. Having said that, 34mph indicated on a speedo is probably just about 30mph in reality - it tends to overread somewhat, if my GPS is to be believed…
I remember when I drove my beloved little Suzuki Samurai at high speeds…how the engine would scream, how the vehicle would start to sway, how the soft top would start to shake loose. How the passengers would shriek “slow down for christ’s sake, she can’t take any more!”. And the speedometer would read at 55 mph.
God I loved that car. Why did I sell her?!! Stupid decision. Now I drive a boring old Toyota Corolla.
I drove a delivery truck for several years. For about two years my regular truck had no speedometer or working dash lights. Never bothered me.
Pretty much every car and truck feels the same to me that I have a pretty good idea how fast I’m going. On the motorcycle it’s different. I look at the dial a lot more. Maybe because it accelerates like mad and I can’t afford any more “awards” for my driving habits from the fellows with shiny lights on their cars.
All the cars I enjoyed had an accelerator-responsiveness tight enough that you could feel engine acceleration or deceleration immediately if you changed the foot-pressure. Barring the effects of hills, that tends to equate to changes in speed. I also knew those cars well enough to have a “seat of the pants” sense of how fast they were going based on little vibrations, the steering characteristics (from the way caster and toe-in angles change a tiny bit with speed, I think), and, again, the accelerator-responsiveness (which itself changes in response to both engine and transmission speed).
Totally, massively different situation if you handed me the keys to an unfamiliar vehicle. I’ve briefly driven large articulated trucks and they feel like they’re going 35 when they’re at 60. (Those big tires probably have a lot to do with it). Similarly, my big old Pontiacs would fool other people, both passengers and the rare/occasional other driver (smooth as silk and solid & stable as an anvil at 110 MPH. Until you hit a curve, that is. Wheee!).
Lots of very bad vehicles were put on the road in the late 1970s and early 80s. Sluggish accelerator responsiveness, with the air, spark, vaccuum, and fuel subsystems doing things more in accord with what crappy slapped-together emission-control devices were telling them than with what you were doing with the accelerator pedal, and, on auto trans cars, similarly messed-up shifting behavior combined with mushy slushy torque converters. As the modern era of pollution control stretched on, the technology got a lot better and so did the responsiveness of cars, but for awhile there I don’t think anyone could tell what their car was doing (or control what it was doing in any precise way).
It seems that way to me, too. When I pass a police-installed automated radar detector that displays your speed, it is always 2 to 3 mph less than what my speedometer says, no matter what type of car I was in.
On the other hand, my testing, by going at a specified speed and calculating what my odometer should read based on both the map and my speedometer lead me to believe that it is accurate, after all. But I don’t have cruise control, so that might not be that accurate. I’m glad I wasn’t the only one noticing these things.
My car has not had a working speedometer in over a year. I drive every day basing my speed on “feel” and, if available, other traffic. Not only have I gotten no tickets, people who have followed me somewhere always comment on how close to the speed limit I drive. Sometimes I even have to prove to them that the speedo is non-functional.
Having been working around cars for over half my life, I can tell you that some people can tell the speed of their car very accurately. There are other that can’t, even with a speedo, GPS, tach, navigator, and a whoop up side the head with a clue by four.
Funny story. Three of us were driving from Vegas to Ely Nevada. Miles and miles of nothing but miles and miles. The bosses’ admin was driving. When we left the interstate she set the cruise at 135 MPH. [Don’t panic here, the road is straight as a string, and as flat as a board] Anyway after an hour or so we got to a small town. Speeding through a small town is not a good idea. I tell her to slow down. She dros down to about 90. I tell her to slow down, she drops to 75. I tell her loudly and forcefully that she has to slow down. She says I am barely moving. I tell her to look at the speedo. :eek: 75 MPH
When I ran the Nevada Open Road Race, after we averaged 149 MPH for 90 miles 55 looked like walking.
Straqnge but true, your perception does change with speed, if you are at speed long enough.
Common on small European cars, usually they replace the tachometer with a clock. Makes little sense to me, cheaper surely to have it on all models and save costs on the different layouts on different models. On my Mum’s Honda Civic it seems that above 2500rpm, the engine really seems to start drinking a lot more fuel, so its very handy on smaller cars.
But to the OP, on the motorway, I sometimes find my speed slowly drifting a little higher than I expect. This I put down to the smooth roads and constant engine speeds. But on smaller roads, where bumps make themselves known, its easier to spot when I’m speeding up.
I still have no idea why listening to a book messes with things, though.