Another monkey puzzle: cars

[Badly Shaved Monkey]

Devoted as most of us are to our internal combustion engines, I think we all tend to dismiss as pointless alternative vehicles that have low top speeds and small ranges. But, the monkey family own two vehicles one a diesel people carrier and the other a 150mph petrol-addict and their on-board computers reveal that over the long term both average 28mph despite their huge differences in potential performance. In london, famously, average veicle speeds are 11mph, a fact I recalled as I watched a Lamborghini violently accelerating all the way to 30mph over Southwark bridge a few weeks ago.

So, the question arises, if we were all confined to machines that could only manage 50, 60 or 70mph maximum, how adversely affected would we really be?

Even on UK motorways I struggle to complete a journey at an average speed of greater than 60mph, so, while we might like the idea of blasting along at 90mph, would an absolute maximum speed of 60 or 70mph make much of a difference to our real average speeds?

I see this as having a significant practical consequence-perhaps the greater emphasis needs to be placed on range rather than speed for vehicles powered by alternatives to internal combustion.

 

[Amapola]

You have some great points here. The sad thing is, people don't seem to actually purchase a vehicle based on practical principles like those you have just outlined. They buy the vehicle based on some perception of what is "cool". So you have all these SUV drivers out there and even though the vehicle is equipped with 4WD they never use it. (And just how likely are they to NEED 4WD in say, Florida?) You have people driving in morning traffic and traveling slower (at times) than they could walk or ride a bike - but instead of walking or biking, they are out there driving. At least, I see that here in the US. Maybe it is different elsewhere.

 

[TjW]

'Cool' certainly comes into it, but I think people buy cars to meet their 'worst case' transportation needs, rather than the everyday commute.
Amapola, if you were limited to one car, would you consider one that couldn't pull a horse trailer?
Some of the commuting SUVs may pull a boat on the weekend.

In my own case, we own a small car, and a van. The small car is used for Mrs. TjW's commute. My own commute is short enough that I could probably use an existing technology electric car with a top speed of 50 mph, if it seated 4, so I could pick up and drop off the kids. But that would have to be a third car, because on the weekends, the van is full of Cub Scouts and Girl Scouts. It's also what we use to take the kids the 400 miles to Grandma's in Arizona.
And yet, most days, there's just me in it.

 

[Badly Shaved Monkey]

I agree 'cool' has a lot to do with it, but if we need to swallow a nasty utilitarian pill in the future, I think we may find that the performance data need not be such a problem. Also, 'cool' is only a problem if cool=fast. If 'cool' can be associated with other features of the vehicles then the problem is smaller. Sure, I like that kick in the back of a quick car, but I think acceleration, albeit to modest top speeds, can be pretty good in some of the alternatives.

Overall, I could much more easily live with a car that would do 400 miles at 50mph than 100 miles at 100mph. I think recharge times must also be a big factor- it's no good if a reasonably long 1-day journey becomes a 2-day expedition because some kind of overnight recharge/refuel is required.

 

[Amapola]

Tjw, I agree with some of what you say. I do think though that people buy things they don't really need, based on the perception that it is "cool". Like that weird truck/car vehicle. Did you ever see those weird commercials? The thing converts somehow, by folding down things etc.

I also see people with trucks who never actually put anything in the bed, and don't have a trailer hitch. (It's usually a souped-up truck, with great big huge tires and about a million lights on it.) And I always wondered about short-bed trucks, since they get the same crappy mileage as a full-sized truck but you can't haul as much stuff in it. It seems to me manufacturers are not sitting down and rationally trying to figure out what someone actually needs, but what they *might* want, maybe, someday. And I think people tend to buy stuff based on how much they think they can do with it. (As an example, I carry one of those multi-tool leatherman type things everywhere I go, and only ever use the knife part.)

I plead guilty on the truck. It has to be able to haul my gooseneck flatbed I use to haul hay out of the fields, and it has to have 4WD both due to snow and hauling hay out of the fields.

 

[Ziggurat]

So, the question arises, if we were all confined to machines that could only manage 50, 60 or 70mph maximum, how adversely affected would we really be?

Internal combustion engines are inefficient at low RPM's, and if you're starting from a standstill at a light, the transmission (manual OR automatic) has to slip a lot in order to keep the engine revving at higher RPM's. Which means that during acceleration from a stop, you need a lot more power than is actually being converted into kinetic energy. A car with an engine with only enough power to drive at 50 mph (or even only at 70) is going to have an absolutely pathetic acceleration. Nobody wants that. And once you get down to engines that small, you're not actually going to be saving much gas anyways compared to larger engines, since the weight of the car will be dominated by the body/frame/interior.

Electric cars are a little different because you can get good torque even at low RPM's, so an electric car that tops out at 70 mph isn't going to be as pathetic when starting from a stop. But range, not speed, is the real problem: doesn't matter if your typical commute is less than 10 miles, if you can't do those occasional weekend trips (WITH the air conditioner on), it's going to be a lot less attractive.

 

[TjW]

I agree 'cool' has a lot to do with it, but if we need to swallow a nasty utilitarian pill in the future, I think we may find that the performance data need not be such a problem. Also, 'cool' is only a problem if cool=fast. If 'cool' can be associated with other features of the vehicles then the problem is smaller. Sure, I like that kick in the back of a quick car, but I think acceleration, albeit to modest top speeds, can be pretty good in some of the alternatives.

Overall, I could much more easily live with a car that would do 400 miles at 50mph than 100 miles at 100mph. I think recharge times must also be a big factor- it's no good if a reasonably long 1-day journey becomes a 2-day expedition because some kind of overnight recharge/refuel is required.

I sure can't disagree about range and refuel/recharge times needing to be reasonable for any "alternative car".
But speaking practically, I am not going to take a car with a 50 mph top speed on the 400 mile trip to my in-laws. Even though it has the same range as my Toyota van, and even though it would technically be legal on the interstate, it would be unsafe.

 

[TjW]

Tjw, I agree with some of what you say. I do think though that people buy things they don't really need, based on the perception that it is "cool". Like that weird truck/car vehicle. Did you ever see those weird commercials? The thing converts somehow, by folding down things etc.

I also see people with trucks who never actually put anything in the bed, and don't have a trailer hitch. (It's usually a souped-up truck, with great big huge tires and about a million lights on it.) And I always wondered about short-bed trucks, since they get the same crappy mileage as a full-sized truck but you can't haul as much stuff in it. It seems to me manufacturers are not sitting down and rationally trying to figure out what someone actually needs, but what they *might* want, maybe, someday. And I think people tend to buy stuff based on how much they think they can do with it. (As an example, I carry one of those multi-tool leatherman type things everywhere I go, and only ever use the knife part.)

I plead guilty on the truck. It has to be able to haul my gooseneck flatbed I use to haul hay out of the fields, and it has to have 4WD both due to snow and hauling hay out of the fields.

Oh, I understand completely. Here in So Cal, I see the jacked-up beasts you're talking about all the time. The ones that particularly amuse me are the ones with actual murals painted on the side. Not how I'd outfit something for going off-pavement.
Also out here is another weird truck phenomena. Little pickups with the rear end lowered so much the rear end drags on the ground. The bed is useless, because they have cut off the fenders and cut big holes in the bed so the tires can come up higher.
Before the van, I had an SUV. I got the occasional sneer about it, to which I would reply: "Me and three other pilots are going to the Owens Valley next week. We'll drive up mining roads in the White Mountains to launch, and with luck, our driver will chase us out into the Great Basin. What should I be driving?" or perhaps ending "... will you rent me your car?"

 

[Dr. Imago]

I think it is an addiction. Bigger, stronger, more powerful seem to be a status symbol. Especially in the U.S. (although may be true elsewhere), we tend to think in terms of larger = better (fill in the blank on what else that could refer to).

Sometimes top speed isn't the issue, but how fast you can get from 0-60 MPH as well. I think if someone would produce a hybrid or an electric car that is as efficient as an internal combustion engine - and that would actually "step out" when you mash the accelerator - then this wouldn't be an issue. Any electric car that is relatively cheap and can go from 0 - 60 in under 5 seconds would be a huge hit. Likewise, I know that when I want to overtake someone in my (I'm almost embarassed to say on this thread) V8 gas guzzler, the power is there when I stomp the accelerator. Getting around a Geo Metro who's in my way is no problem at all.

This is the real crux of it, I think. It's not so much the top speed. I can't remember the last time I went over 75 MPH. I think there are probably some engineering tricks you could employ that would accomplish a rapid acceleration in a non-internal combustion vehicle, but this will cost time and, perhaps more importantly, money for car manufacturers to develop. Right now, the economics just aren't there to advance such technology... without governmental incentive, that is.

-Dr. Imago

 

[The Don]

So, the question arises, if we were all confined to machines that could only manage 50, 60 or 70mph maximum, how adversely affected would we really be?

Enough....

About 4 years ago I used to commute to Surrey from Bristol, a distance of 110 miles or thereabouts. I used to set off very early so traffic wasn't an issue. I used to drive along the motorways at around 85mph. I took me 100 minutes to get to work.

As an experiment, I tried travelling at a maximum of 70mph. It took 25 minutes longer to get to work. A little of this was due to extra traffic on arrival (It'd be closer to 7.30 am rather than 7.00 when I arrived) but I estimate that 20 minutes was due to travelling slower. Call it 3 hours a week.

 

[Badly Shaved Monkey]

Enough....

About 4 years ago I used to commute to Surrey from Bristol, a distance of 110 miles or thereabouts. I used to set off very early so traffic wasn't an issue. I used to drive along the motorways at around 85mph. I took me 100 minutes to get to work.

As an experiment, I tried travelling at a maximum of 70mph. It took 25 minutes longer to get to work. A little of this was due to extra traffic on arrival (It'd be closer to 7.30 am rather than 7.00 when I arrived) but I estimate that 20 minutes was due to travelling slower. Call it 3 hours a week.

I think that is a significant counter-example. But as a counter to that (!) if motorway speeds continue to drop because of congestion, the opportunities to travel at a consistent 85mph will decline. Another factor, at least according to the principle of those variable speed limit signs, is that if we were limited to a lower top speed there is meant to be less chance of accident and consequent gridlock. My recent anecdotal experience of the travelling the M25 from M11 to A3 is making me considering adopting the habits of my parents in the 1960's, i.e setting off at ridiculously early times to avoid the congestion. I might happily trade a reliable 2.5hr run for 120miles instead of an unpredictable 2 to 5 hours!

 

[The Don]

Sure, the reason I was leaving at that ridiculous hour of the morning was to "enjoy" the same traffic conditions I would have had 10 years earlier had I set off an hour later.

The real problems as I see it are:
- Travel is stll too cheap, we can afford to travel a long way to work
- Unless both start point an destination are well served by direct public transport then it's non-starter
- More people in work
- More people ferrying kids around to schools of choice (rather than walking to the nearest one)

If a vehicle is limited to xx mph then I agree, it should be able to get there quickly.

Range is still an issue though for non-IC vehicles. The ranges quoted are optimum ranges (achieved at speeds well below what we would consider acceptable) and are still a factor of 4 or 5 too small.

Unless of course we completely re-engineer our lives. This then goes back to the idea of a family having one or two alternatively fueled cars for town work and an IC vehicle (or access to same) for inter-city work.

 

[chriswl]

Even on UK motorways I struggle to complete a journey at an average speed of greater than 60mph

Well, with a speed limit of 70 mph it is going to be tough to average more than 60. On the other hand if motorways were deristricted like German Autobahns then the top speed of your car would make a big difference.

so, while we might like the idea of blasting along at 90mph, would an absolute maximum speed of 60 or 70mph make much of a difference to our real average speeds?

If your car could only just do 70 mph it would take ages to reach that speed and you would slow right down again everytime you encountered even a slight gradient. Driving a car with a top speed of less than 100mph on a motorway is a tiring business. Get stuck behind a lorry in the slow lane and you just haven't got the acceleration to pull out and gave to wait for a huge gap in the traffic. The more crowded the motorway the more you find yourself slowing down and speeding up again and the more you want something that will accelerate you back up to 70 or 80 quickly.

I see this as having a significant practical consequence-perhaps the greater emphasis needs to be placed on range rather than speed for vehicles powered by alternatives to internal combustion.

We already have the answer - for long journeys modern turbo-diesels are very fuel-efficient but still have loads of performance. Around town hybrids are very efficient. What we need is diesel-hybrids.

 

[Almo]

Stupid:

I saw a Hummer in the middle of London. He barely fit.

 

[richardm]

If your car could only just do 70 mph it would take ages to reach that speed and you would slow right down again everytime you encountered even a slight gradient.

Not necessarily - many high performance cars already have a speed limiter built in (an informal agreement between companies). So you could still have a large engine, but reined in. This probably defeats the object of the exercise somewhat, I suppose.

How about if instead of building new pylons for electricity distribution we lay the cables under motorways. Then cars on the motorway can get their power through induction for their electric motors, and you can turn the petrol one off.

 

[Dymanic]

Internal combustion engines are inefficient at low RPM's, and if you're starting from a standstill at a light, the transmission (manual OR automatic) has to slip a lot in order to keep the engine revving at higher RPM's. Which means that during acceleration from a stop, you need a lot more power than is actually being converted into kinetic energy.

And as speed increases, so does aerodynamic drag, and the kinetic energy required to overcome it. In fact, it increases as the square of the velocity, so rapid acceleration isn't the only thing with a high price tag; maintaining that convenient high average speed is costly as well. Even when traffic conditions permit. Which they seldom do, most places. Somewhere around 40 mph is the sweet spot at which the average vehicle achieves an optimum balance between engine efficiency and wind resistance.

It's not just the vehicles we drive, or the roads we drive them on. It's how we drive the vehicles we drive on the roads we drive them on.

How about electronically-controlled roadways (where only vehicles equipped with the required sensors and governors were allowed) on which top speeds were determined by computer so as to optimize flow?

 

[chriswl]

How about electronically-controlled roadways (where only vehicles equipped with the required sensors and governors were allowed) on which top speeds were determined by computer so as to optimize flow?

They are trying to do a crude version of this on the UK's M25 motorway. Variable speed limits are enforced by speed cameras, the idea being to get rid of the stop-start driving and have traffic keep moving.

It doesn't work. You still end up in stationary jams, looking at the illuminated signs warning you not to go more than 40 mph - if only.

 

[chriswl]

And as speed increases, so does aerodynamic drag, and the kinetic energy required to overcome it. In fact, it increases as the square of the velocity, so rapid acceleration isn't the only thing with a high price tag; maintaining that convenient high average speed is costly as well.

This also affects trains too. Slow commuter trains packed with passengers are very efficient. But very high speed trains aren't. Eurostar trains produce as much CO2 per passenger as aeroplanes even though they are only one third the speed. Planes reduce drag by flying at high altitude where the air is very thin, trains are stuck at ground level.

 

[jimlintott]

I have to point out that I concur with the couple of posters who say that just because a car is speed limited doesn't mean it won't accelerate. With today's computerised control systems it would be easy to speed limit a car. At one mph over the limit it bounces off a rev limiter. Anything under that and full power is available. You could even put in a push to pass button that could override the rev limiter for 30 seconds just so you could get by someone. Speed limiting is trivial with today's auto tech.

I live in the land of pickup trucks. Saskatchewan is about the same land area as Texas and has a population of about one million. We have lots of empty roads and countless unpaved roads. The pickup truck is the new muscle car. Around here the right pickup is a babe magnet.

Now my little economy car gets better mileage in the city than most of the pickups do on the highway. It also has about the same horsepower to weight ratio that the pickups with the big motor have. While I can't carry a load I have no problem passing anything and my little car will accelerate from 110kmh to 160kmh quite briskly. You don't have to give up performance for economy. What I gve up is space and ride. The short wheelbase can be a little choppy and it is sprung quite firmly. I like that but other people don't.

As for traveling fast I find that for short trips (around two hours) it doesn't matter much. You don't really save much time. If I'm driving all day then 20 extra kmh can add up to a lot in a day. Keep in mind that I would consider a normal day driving to travel 1200 km (745 miles). That is twelve hours at 100k but 10 hours at 120k. I have also found that travelling this kind of distance at speed (varying from 140k to 180k) gets you there quicker but far more fatigued and it is much more stressful (not to mention dangerous). I also find driving slowly for a long time to be similarly stressful and tiring.

So much of it is attitude. I chose my car because it is economical to own and operate. It suits my daily needs perfectly. Unfortunately too many car owners choose their vehicle not on their needs but their perceived social status. Now fuel prices are going to put them in the poorhouse.


ETA: I was starting to ramble so I just hit post!

 

[Ziggurat]

I have to point out that I concur with the couple of posters who say that just because a car is speed limited doesn't mean it won't accelerate. With today's computerised control systems it would be easy to speed limit a car. At one mph over the limit it bounces off a rev limiter.

Yeah, but that's even stupider. Imagine two cars, each mechanically identical, and which cost exactly the same. One car is artificially speed-limited, the other is not. Which one is your typical consumer going to buy? The non-speed-limited one, of course, because it can do everything the speed-limited car can do and more, so it's an obviously better buy. Why, then, would any car maker ever artificially restrict the speed limit on a consumer car? They wouldn't, and they don't. Artificial speed limits do not provide a consumer any benefit. If you want to stay under a certain speed to conserve fuel, you don't need the car to do that for you. The only case where this might get any demand is when the driver is not the owner, such as rentals or commercial fleet vehicles, where the owner wants the cars driven differently than the actual driver might choose. But that's not the majority of cars (and even with rentals, if you set the speed too low you're going to get consumers bailing to competitors). So if you want to talk about speed-limited cars for consumers, you're basically only going to be talking about cars without enough power to driver faster than a certain speed.