High Speed Highways

[henryj]

Here in Texas they are debating raising the speed limit to 85mph on some interstates. Normal speed limit is going to be raised to 75 day and night doing away with the 65mph restriction at night. So in place of high speed trains looks like we will get high speed buses and cars.

 

[Anderson]

To be fair, there are places in Texas where "good" train service wouldn't be even vaguely economical (out in the land of 500-people-to-a-county in particular), where the land is flat, and moreover where folks are already doing 80-85 without being given permission to do so. But once you go above about 65-75, gas mileage really starts going downhill (I know that efficiency peaks around 60 or so, but I don't know what the falloff looks like. So call it a mixed bag policy: On the one hand, it's not a great policy...but on the other hand, in a lot of those areas, it is more an admission of reality than a change that'll result in different behavior. I expect that the tickets will be quite stiff above about 90 MPH even after the speed hike (they tend to be stiff above 80 most of the time anyway).

 

[jis]

Here in Texas they are debating raising the speed limit to 85mph on some interstates. Normal speed limit is going to be raised to 75 day and night doing away with the 65mph restriction at night. So in place of high speed trains looks like we will get high speed buses and cars.

you do realize of course that 75mph or 85 mph is not particularly high speed by German standards - you know.... those guys that invented divided multiple carriageway limited access highways and still run the best of them?

 

[MrFSS]

Here in Texas they are debating raising the speed limit to 85mph on some interstates. Normal speed limit is going to be raised to 75 day and night doing away with the 65mph restriction at night. So in place of high speed trains looks like we will get high speed buses and cars.

you do realize of course that 75mph or 85 mph is not particularly high speed by German standards - you know.... those guys that invented divided multiple carriageway limited access highways and still run the best of them?

How fast to they go on some of those Autobahns, if you know?

 

[ALC Rail Writer]

Here in Texas they are debating raising the speed limit to 85mph on some interstates. Normal speed limit is going to be raised to 75 day and night doing away with the 65mph restriction at night. So in place of high speed trains looks like we will get high speed buses and cars.

you do realize of course that 75mph or 85 mph is not particularly high speed by German standards - you know.... those guys that invented divided multiple carriageway limited access highways and still run the best of them?

How fast to they go on some of those Autobahns, if you know?

Most sections don't have limits, only a recommendation of 130kph, about 81mph. I've seen cars on TV pull 160kph and much higher without hassle.

 

[MrFSS]

Here in Texas they are debating raising the speed limit to 85mph on some interstates. Normal speed limit is going to be raised to 75 day and night doing away with the 65mph restriction at night. So in place of high speed trains looks like we will get high speed buses and cars.

you do realize of course that 75mph or 85 mph is not particularly high speed by German standards - you know.... those guys that invented divided multiple carriageway limited access highways and still run the best of them?

How fast to they go on some of those Autobahns, if you know?

Most sections don't have limits, only a recommendation of 130kph, about 81mph. I've seen cars on TV pull 160kph and much higher without hassle.

Last time I was in Germany I couldn't get anyone to really tell me how fast some of them went. We were on a tour bus and they had a limit but the Mercedes would pass us as if we were standing still. :mellow:

 

[ALC Rail Writer]

Yes buses and trucks, as well as older cars have restrictions. You can be pulled over if the officer thinks you or your vehicle is not experienced enough for the road.

The Germans have a much more rigorous licensing process, including a requirement in First Aid training.

I think TopGear summed the Autobahn up best when they said, "It is limitless within reason."

 

[henryj]

In the 1960's I had the priviledge of experiencing the German Autobahn's courtesy of the US Army. I only had a Volkswagen so I stayed mostly in the right lane. Later when I was back in the US, before the fuel crisis of the 1970's, I took a trip up to Canada, the Pacific NW and back in my new Alfa Romeo. There were two states with no speed limits. Montana and Nevada. Crossing Montana, people seemed to not pay any attention to the lack of speed limit, driving most responsabily and safely. On my way back cutting across the Nevada desert all traffic seemed to move at 90mph and it still seemed slow. When I got to Utah, which had an 80mph speed limit, everyone was doing their best to do 80mph even if it destroyed their car, just because that is what was posted. lol. Texas already has an 80mph speed limit on I10 west of San Antonio(and probably I20 also) so raising it to 85 is no big deal. Speed limit at night is still 65. However, raising the current 70mph limit across the board to 75 day and night is a big change. Perhaps they think it will raise more money through the fuel tax. Or perhaps this is their answer to the increased support for high speed rail.

 

[GlobalistPotato]

My mom hates this idea and she thinks it's being sponsored by the Republican Party to make us consume more fuel and jeopardize our safety.

Oh mom, I don't like the Republicans, but transportation shouldn't be a partisan issue.

(The fact is that drivers going 80mph make up very little of the overall fuel consumption on our highways.)

The roads that will be getting this speed hike are in West Texas; I've rode on some of those roads on the way to a church retreat in Canyon. Those roads are practically empty, and we consistently made 80mph while driving. These roads could handle speeds up to 100mph; it's just that the other drivers on the road tend to act stupid. :help:

And while we're on the topic of speeds... if it wasn't for the 79mph rule and the Class # track classifications, then most of the straight, flat railroads could handle speeds at up to 110mph. In fact, it wasn't too uncommon for ATSF to run their trains at up to 100mph across the plains in order to make up lost time. :lol:

 

[Ozark Southern]

Here in Texas they are debating raising the speed limit to 85mph on some interstates. Normal speed limit is going to be raised to 75 day and night doing away with the 65mph restriction at night. So in place of high speed trains looks like we will get high speed buses and cars.

you do realize of course that 75mph or 85 mph is not particularly high speed by German standards - you know.... those guys that invented divided multiple carriageway limited access highways and still run the best of them?

How fast to they go on some of those Autobahns, if you know?

I've been on the Autobahn in Berlin, and in the city it's only 100kph. The quality of the highways was much the same as any large American city (though I never saw any Autobahn with more than six lanes).

 

[Green Maned Lion]

I fail to understand people who don't follow politicians. They want votes to be elected. If waving a battle axe loudly at minor federal programs gets them votes, watch the sales spike in battle axes. If looking to cut taxes for the rich gets them votes, listen for the tax cuts. If promising socialized medicine does it, watch for socialized medicine. If chopping off their dead grandpas wedding tackle and feeding it to their grandma for dinner does it... etc.

Its really that simple.

 

[Ryan]

Here in Texas they are debating raising the speed limit to 85mph on some interstates. Normal speed limit is going to be raised to 75 day and night doing away with the 65mph restriction at night. So in place of high speed trains looks like we will get high speed buses and cars.

you do realize of course that 75mph or 85 mph is not particularly high speed by German standards - you know.... those guys that invented divided multiple carriageway limited access highways and still run the best of them?

How fast to they go on some of those Autobahns, if you know?

Most sections don't have limits, only a recommendation of 130kph, about 81mph. I've seen cars on TV pull 160kph and much higher without hassle.

I was visiting a friend over there, we (he was driving, I was a scared little girl in the back seat) explored the 250km/h to 300km/h realm.
Most astounding.

Just like US HSR, our speed limits are only "high" compared to the rest of what's around here.

 

[GlobalistPotato]

I fail to understand people who don't follow politicians. They want votes to be elected. If waving a battle axe loudly at minor federal programs gets them votes, watch the sales spike in battle axes. If looking to cut taxes for the rich gets them votes, listen for the tax cuts. If promising socialized medicine does it, watch for socialized medicine. If chopping off their dead grandpas wedding tackle and feeding it to their grandma for dinner does it... etc.

Its really that simple.

If actually acting sane gets them votes, then they'll do that...

 

[Devil's Advocate]

Once you go above about 65-75, gas mileage really starts going downhill (I know that efficiency peaks around 60 or so, but I don't know what the falloff looks like.

In general the highest efficiency will occur while traveling the slowest possible speed in the highest possible gear. That's likely to be somewhere between 40MPH and 50MPH for many conventional vehicles and was probably the basis for the 55MPH federal speed limit.

Last time I was in Germany I couldn't get anyone to really tell me how fast some of them went. We were on a tour bus and they had a limit but the Mercedes would pass us as if we were standing still.

Most small cars are going to be internally limited to around 120MPH. Luxury sedans and sports cars will generally be limited to around 150MPH to avoid causing too much damage to the drivetrain. There are a few supercars than can reach 200MPH on a track but that's not really practical on a conventional road, even one that's as well designed and maintained as the autobahn.

My mom hates this idea and she thinks it's being sponsored by the Republican Party to make us consume more fuel and jeopardize our safety.

I didn't originally believe that Republicans were actively trying to increase pollution, but in the last several years I've run out of other explanations. How else can you explain laws like the one that specifically prevents any Texan agency from lowering speed limits for the purposes of reducing pollution?

The fact is that drivers going 80mph make up very little of the overall fuel consumption on our highways.

Actually it's a huge consumption issue. Driving 80MPH+ is far less efficient than driving 55MPH as per the speed limits that were in effect when I moved to Texas. Nothing I've yet seen has challenged that conclusion.

 

[Anderson]

I don't think it's "We want to increase pollution"...it's "We don't give a **** about pollution". There's a difference.

For the record, the Nixon administration thought that 50 MPH was where efficiency peaked. I think the understanding is that it's a little higher (and it's probably changed some over the years as engines changed around, etc.).

Moving the limit up to 65 MPH was more a concession to how badly-flouted the law was and the utter lack of support for it. You had a couple of states that flouted the limits as best they could while officially retaining the 55 MPH limit.

 

[WhoozOn1st]

Wow, can I call anything high speed and start a topic about it here?? COOL!! Let's talk about High Speed Snails! How 'bout High Speed Riding Lawnmowers? Even better, High Speed VIA Rail!! Oh wait, that's still actually rail. Can't have THAT.

Hopefully the coming changes will address the exploding problem of misplaced topics, those who persist in placing them, and lackadaisical moderation that allows it to continue unabated. High speed buses, anybody?

 

[reefgeek]

Wow, can I call anything high speed and start a topic about it here?? COOL!! Let's talk about High Speed Snails! How 'bout High Speed Riding Lawnmowers? Even better, High Speed VIA Rail!! Oh wait, that's still actually rail. Can't have THAT.

Hopefully the coming changes will address the exploding problem of misplaced topics, those who persist in placing them, and lackadaisical moderation that allows it to continue unabated. High speed buses, anybody?

Look everybody, high speed sarcasm! :lol:

 

[Alice]

Wow, can I call anything high speed and start a topic about it here?? COOL!! Let's talk about High Speed Snails! How 'bout High Speed Riding Lawnmowers? Even better, High Speed VIA Rail!! Oh wait, that's still actually rail. Can't have THAT.

Hopefully the coming changes will address the exploding problem of misplaced topics, those who persist in placing them, and lackadaisical moderation that allows it to continue unabated. High speed buses, anybody?

Look everybody, high speed sarcasm! :lol:

Patrick doesn't know yet that some important High Speed Riding Lawnmower events are scheduled along the "Team Whooz Crosscountry Ragin' Rails & Roads Raid" route. Schedule

 

[ALC Rail Writer]

Interesting thought-- an 85mph 18-wheeler is not just a missile, it's a gas guzzler.

 

[bretton88]

By the way, the Pew Center for Research states that 47.5mph is the peak fuel efficiency (I can't find the link, it was presented in a traffic engineering class of mine). However, 85 mph is still much more efficient than 35mph (basically city speeds) so this really won't change the fuel consumption overall. The decline after 47.5 is a really slow decline.

 

[George Harris]

Thw whole 55 mph thing was supposedly to save gas during the early 70's "gas cricis". Also recall that the initial anti-pollution changes on cars drove the gas milage through the floor. It only made sense in the northeastern areas where you cross entire states in a couple hours or less. It never made ssense naywhere lese in the country. It was for the most pat a typical political "We must do something or at least look like we are doing something" response.

There are a lot of miles of road out there that are safer at 80 mph than the roads they replaced were at 50 mph.

In this whole issue we are forgetting the monetary value of time. You say it is not a consideration? Do that mean that you are willing to accept the same amount of money for 16 hours that you do for 8? Of course not.

 

[ALC Rail Writer]

By the way, the Pew Center for Research states that 47.5mph is the peak fuel efficiency (I can't find the link, it was presented in a traffic engineering class of mine). However, 85 mph is still much more efficient than 35mph (basically city speeds) so this really won't change the fuel consumption overall. The decline after 47.5 is a really slow decline.

Your car will heavily impact this. I suspect that my 99 Neon gets worse mileage at 85 than an 09 Mustang V6.

 

[trainman74]

I suspect that my 99 Neon gets worse mileage at 85 than an 09 Mustang V6.

I remember having a '99 Neon as a rental car in 1999, and I'm surprised to find out they can get up to 85.

My Garmin Nuvi GPS has a "green rating" of 0-99 on the display, presumably programmed by someone who knew what they were doing. It gives a 99 rating when you're keeping a constant speed between about 50 and 70; higher than that, and it drops off, but only slightly -- if I recall correctly, it'll be at 95 if you keep a constant 85. (Hard to recall because I've only done that briefly.)

 

[Oldsmoboi]

I support this idea as a natural extension of Darwinism.

That said, I've done 180kph on the German Autobahns in the past (electronically limited by the car)

 

[Oldsmoboi]

The fuel economy of cars at various speeds varies greatly by model, engine, and transmission. Some "high efficiency" cars start to drop off in efficiency substantially once you crest 65mph.... two recent examples I've tested where that was the case were the Ford Fiesta Hatchback with a 5-speed manual and a Chevrolet Cruze LTZ with a turbo 4-cylinder and 6-speed automatic.

In the Fiesta, the fuel economy drops rapidly because the car simply isn't powerful enough (and is missing a 6th gear) to move the car at 75mph without the engine turning over 3,500 rpm.

In the Cruze, in an effort to keep a 138horsepower car feeling "peppy", they made a very short final drive ratio such that even when the car is in 6th gear and overdrive, 70mph drops the fuel economy into the high 20s from the mid-30s. Driving that Cruze from Pittsburgh to Detroit, I averaged 27mpg.

Contrast that with a 2011 Lincoln MKS AWD Turbo V6. It's a 350hp AWD and heavy sedan. Yet over the same exact route and speed as the Cruze, I was able to average an identical 27mpg.