Drivers who can't discern between safe following distance and going slowly

[jgs]

Let's not pull strawman arguments, k?

I really didn't intend any such thing. I was just trying to read your prose as you wrote it. As a reminder, what I was picking on was "the slower you go (back in the older cars) the less road fatalities they had". I can't see any straightforward reading of that sentence where the parenthetical isn't intended to imply that it's drawing a contrast to newer cars where (by implication, because why else draw the contrast) there is NOT a similar correlation between speed and road fatalities.

Accepted that you didn't intend to say that.

 

[GlmnAlyAirCar]

I would very much like to see Tesla provide the option to make the 'safety gap' relative to speed rather than an absolute number of car lengths.

It's not absolute car lengths; it is based on speed. What gave you the impression it was otherwise?

 

[jgs]

You could make statics look like anything you want, but here's a good one: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=13&ved=0CFYQFjAM&url=http%3A%2F%2Fwww.nhtsa.gov%2Fstaticfiles%2Fnti%2Fenforcement%2Fpdf%2F809839.pdf&ei=NdSfVZLwDo-YyATnm4LgCw&usg=AFQjCNH5WXQjm9nBVxWT5b_r8hmwct8lLw&bvm=bv.97653015,d.aWw&cad=rja

Page 9. THere are a lot more deaths at 50-55mph than there are at 60+mph. It could be the number of roads with that many speed limits.

That's interesting, thanks. I think you are right with your caveats though. Further, the stats in that paper relate to speeding-related related deaths, not speed-related as such. They don't tell us how fast the vehicle was moving, just that it was moving faster than the given speed limit.

And as you say, attributing cause is fraught. So for example, I could speculate that 100% of the accidents in 60+ mph speed limit zones take place on limited-access highways which are known to be safer than general roadways, or that people are more likely to speed egregiously on 50-to-55 mph roads which often are either rural state roads or crowded urban limited-access highways. But I don't think any of it advances the conversation much.

Anyway, thanks for sharing.

 

[mknox]

When speed limits are raised...

Okay. But I'm talking about people who speed when the limits aren't legally raised.

The video very correctly is talking about 50 km/h (30 MPH) stretches or road that are clearly just speed traps. I get that. The video is expounding the view that speed limits should be set based on engineered criteria and not on the potential for maximizing traffic tickets. Again agree. There was even a segment showing a car not moving over to the right. Again, right on. That video mainly focussed on surface streets with excessively low (speed trap) limits whereas I was thinking in terms of freeway travel.

 

[Max*]

I really didn't intend any such thing. I was just trying to read your prose as you wrote it. As a reminder, what I was picking on was "the slower you go (back in the older cars) the less road fatalities they had". I can't see any straightforward reading of that sentence where the parenthetical isn't intended to imply that it's drawing a contrast to newer cars where (by implication, because why else draw the contrast) there is NOT a similar correlation between speed and road fatalities.

Accepted that you didn't intend to say that.

Point taken. My parenthetical emphasis was... well... misrepresenting the point I was going for. I put it in more in tune with the history vs. present argument of speed limit reasons and car safety advancements.

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Okay. But I'm talking about people who speed when the limits aren't legally raised.

I think the disconnect is that you believe that laws are meant to be followed, including speeding, hence anyone breaking the law is wrong and putting everyone else in danger. And instead of having people speed, the speed limit should be raised.

What I'm saying, is that I agree that speed limits should be raised. Given today's unrealistic speed limits people will speed, it's inevitable. It's safer to go with the flow of traffic (as shown from AnOutsider) than it is to blindly follow the speed limit; even if it's illegal.

 

[Cottonwood]

Again, gas (or electric) mileage is still proportional to speed -- indeed, the cube of speed, as I've learned by reading other threads here on TMC. Can't fool mother nature.

This is a common error. For the aerodynamic components only, not including HVAC, tire resistance, etc:

• Energy Usage (Wh/mi or L/100km) goes up as the square of speed.
• Power Needed (kW or HP) goes up as the cube of speed.

 

[tezzla]

So what I'm hearing is: We need the levels set from 0-7 instead of 1-7.

0 = tailgating
1-6 = pick your poison
7 = cruising without a care

Here in LA, I think most people would prefer our cars were set to .5

 

[jgs]

This is a common error. For the aerodynamic components only, not including HVAC, tire resistance, etc:

• Energy Usage (Wh/mi or L/100km) goes up as the square of speed.
• Power Needed (kW or HP) goes up as the cube of speed.

Thanks. Yes, now I remember the whole chain of logic that gets us to the cube result (and yes, I get that it only applies to aerodynamic, although my understanding is that dominates at high speeds). Hopefully I won't forget again.

 

[neroden]

One of my biggest frustrations with TACC is not my car, it's with motorists who see a safe following distance in front of me and immediately decide that the gap must be because I'm going more slowly than the traffic in front of me. First they tailgate, then they whip around me with a angry look (or gesture), and then they dive into the gap in front of me. Never once realizing that I'm going the exact same speed as the car they're now following.

This sort of reckless driving is endemic in the US and really, really annoying. Idjits should have their licenses revoked, but we don't really have a driver licensing system in the US.

I'm sure this happened before but it's probably more noticeable now that I more consistently follow from a safe distance, thanks to TACC.

Oh God yes it was happening before. I always keep a safe following distance and I basically can't take Interstates any more (except a few really uncrowded rural ones) because of the epidemic of reckless driving.

I find the reckless, hurried, tailgater, dangerous-passing drivers have a preference for the Interstates, so where there is an Interstate I now take the parallel rural road. If there's no Interstate, however, the same idjits are on the rural road.

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I don't have autopilot feature on my car but I felt like commenting on this thread:

One of the main reason for accidents on freeways is that there is not enough braking distance between cars. What you guys have said has happened to me also and I just stopped getting frustrated because it is not worth it.

I sincerely hope those idiots trying to whip in front don't meet with accidents

You are a kind person. I sincerely hope they don't injure anyone else in a crash -- but at this point, I hope those idiots get in single-car accidents which kill them and get them off the road pernamently. Because we don't seem to have any other way of getting them off the road in this country.

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Speed limits were set back in the 70s (80s?) for most efficient gas mileage and based on the fact that the slower you go (back in the older cars) the less road fatalities they had.

That's still true; the slower cars are going the fewer road fatalities there are. Period. Lots and lots and lots of studies proving this, pretty much a new proof of it every year.

And roads are intentionally WAY over-engineered to provide an extra buffer of safety (curves, rain, etc.).

No, they aren't. SOME of them are, and it depends where you live. They sure as hell aren't in upstate NY. The rural roads are incrementally-upgraded HORSE PATHS, and the Interstates were mostly designed in the 1930s, with a few as late as the 1950s.

But there are still lunatics intentionally tailgating at 80 mph (even though the top speed limit in the state is 65) *sigh*.

 

[7racer]

This sort of reckless driving is endemic in the US and really, really annoying. Idjits should have their licenses revoked, but we don't really have a driver licensing system in the US.


Oh God yes it was happening before. I always keep a safe following distance and I basically can't take Interstates any more (except a few really uncrowded rural ones) because of the epidemic of reckless driving.

I find the reckless, hurried, tailgater, dangerous-passing drivers have a preference for the Interstates, so where there is an Interstate I now take the parallel rural road. If there's no Interstate, however, the same idjits are on the rural road.

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You are a kind person. I sincerely hope they don't injure anyone else in a crash -- but at this point, I hope those idiots get in single-car accidents which kill them and get them off the road pernamently. Because we don't seem to have any other way of getting them off the road in this country.

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That's still true; the slower cars are going the fewer road fatalities there are. Period. Lots and lots and lots of studies proving this, pretty much a new proof of it every year.

No, they aren't. SOME of them are, and it depends where you live. They sure as hell aren't in upstate NY. The rural roads are incrementally-upgraded HORSE PATHS, and the Interstates were mostly designed in the 1930s, with a few as late as the 1950s.

But there are still lunatics intentionally tailgating at 80 mph (even though the top speed limit in the state is 65) *sigh*.

I think that is unfortunately older counter thinking than what is actually occurring. That is that slower cars DO NOT decrease fatalities and most interstates are designed for higher speed limits. People don't drive 80 on back roads in general.

Here is a good reference to illustrate the point
Transportation Expert: Lets Raise The Speed Limits

 

[7racer]

I'm here in Europe currently and really believe that the drivers are better here. They can better judge the "safe" buffer distance and if they have a large one, they are in the right hand lane, not the passing lane. Even going up escalators, people stand on the right and allow walks (people going faster) on the left.

I definitely did not see any accidents on the escalator (tongue in cheek to keep the discussion light)

 

[Max*]

I'm here in Europe currently and really believe that the drivers are better here. They can better judge the "safe" buffer distance and if they have a large one, they are in the right hand lane, not the passing lane. Even going up escalators, people stand on the right and allow walks (people going faster) on the left.

I definitely did not see any accidents on the escalator (tongue in cheek to keep the discussion light)

American drivers suck. Drivers education here is non existent. They give a license just about anyone....

 

[7racer]

American drivers suck. Drivers education here is non existent. They give a license just about anyone....

I agree, pretty evident when you travel. I live in Dallas where people just seem to hang out in the left hand lane and don't pay attention (see the thread of my wrecked Roadster (1400))

I will be traveling to Germany after my meeting in Vienna to do a 2 day track day at the Nurbergring. Should be a refreshing change from US drivers.

 

[Tamar]

I'm appalled at how poor driving is these days, especially in cities on freeways. Tailgating, frequent lane changes, lane changes that threaten to clip the car that's being passed, and not staying anywhere near the middle of the lane you are in when passing are all things I'm seeing a lot of recently. All of those are not only inconsiderate but dangerous, and with my new 85D they are driving me nuts. I haven't even been bold enough to try TACC yet.

 

[pmadflyer]

I wouldn't say only happens with TACC. I drive my classic 85 a few car lengths back from the car in front of me, and travel at the same speed as the car in front. And drivers pass me and whip in front (having to hit their brakes since they are going faster than the car in front of me).
There will always be drivers that think being a car length ahead is a big deal. (This is on a single lane road in the country without congestion).

As the OP suggested, maybe you notice it more now that you are using TACC.

Sorry, I'm on the first page in the thread, so I might be repeating someone else's comments.
On a class II two-lane highway, motorists are more likely to become aggressive and attempt dangerous overtake methods if they are following another vehicle. Source: Transportation Engineering lecture. Class I and Class II two-lane highways are high traffic connections or scenic routes where drivers are content with high speed travel from A to B, or slow speeds (respectively) regardless (mostly) of following distance.

Edit: after reading the thread.

In the Highway Capacity Manual the multi-lane basic highway speed is based at 75.4 miles per hour, under the following conditions:
- 12 foot wide lanes
- 6 foot minimum right shoulder clearance from obstacles.
- 2 foot minimum median lateral clearance.
- only passenger cars
- 5 or more lanes each direction (urban only)
- 2 mile or greater interchange spacing
- level terrain (<2%)
- mostly familiar drivers.

Any deviation from these factors is looked up on tables and the capacity and flow speed are adjusted accordingly.

For a speed posted on a turn, 80% of drivers can handle it in the worst expected conditions.

The interesting thing about the 75.4 mph number is that if you do long distance travel, people without cruise control will gravitate toward that speed. It's an average of thousands of observations.

 

[neroden]

Here is a good reference to illustrate the point
Transportation Expert: Lets Raise The Speed Limits

Like I thought it would be, he's from Texas. Probably never left the state in his life.

Yes, there are some roads in Texas engineered for 85 mph.

There aren't ANY in New York. And yes, we have lunatics going at those speeds. And yes, people do drive 80 mph on back roads, like maniacs. I've watched people driving 70 mph + on roads which are suitable for less than 45 mph.

 

[7racer]

Like I thought it would be, he's from Texas. Probably never left the state in his life.

Yes, there are some roads in Texas engineered for 85 mph.

There aren't ANY in New York. And yes, we have lunatics going at those speeds. And yes, people do drive 80 mph on back roads, like maniacs. I've watched people driving 70 mph + on roads which are suitable for less than 45 mph.

It's been a while since have driven the highways in NY. I am sure that there are areas that aren't safe.

But I think a majority of major highways can handle the 80. Even though he is from Texas I don't think he looked just at Texas highways for his data.

I am in Germany right not running the Nurburgring. Driving on the autobahn from Frankfurt to Nurberg has been a treat.

People in the left hand lane go fast and people that are going slower actually look in their rear view mirror and pull over.

Not only that there were areas of construction and lanes that split and also dropped to just two. Everyone saw it slowed down, then picked up the pace once cleared.

No need for a sign to slow down or a speed limit set arbitrarily low.

Like you mentioned, most people might not ever been out of their state. Most should try a state with higher speed limit or even better Germany.

 

[mmccord]

Like I thought it would be, he's from Texas. Probably never left the state in his life.

Yes, there are some roads in Texas engineered for 85 mph.

There aren't ANY in New York. And yes, we have lunatics going at those speeds. And yes, people do drive 80 mph on back roads, like maniacs. I've watched people driving 70 mph + on roads which are suitable for less than 45 mph.

What's wrong with I84 & I87 that you can't do 85 safely?

 

[AnOutsider]

I think Mr Nerode is narrowing his observations to the New York City area. Thinner roads, lots of congestion/turns. Get out into the rest of New York STATE and there's lots of wide open space.

 

[7racer]

just another interesting observation, the roads around the ring are a single lane roads one direction each way. I also did a little trip to cologne which involved some back roads....I mean Germany in a lot of areas is very rural and farmish. On a particular stretch, I was doing 130km/h (that's 80.8 mph) to us metric challenge folks....and I was getting pushed from behind and taking corners pretty fast (this coming from a track guy)...and the person pushing me? No not one of the track cars from the ring....a lady in a MB SUV then a VW jetta whom I let pass!!!

So while some think 80mph is maniac speed on back roads, I really think its the quality of the driver as the Germans seem to have better training and courtesy to other drivers.