Speed differentials on a road

[Rhea]

Sitting on my porch and a car goes by every now and then. It’s interesting how different the speeds are. Some people do it at 60mph, others do it at 25mph. Which itself is a bit of a danger, right?

Technically the speed limit is 55mph. But there has NEVER been a speed check on this road in the 30 years we’ve been here. So some folks barrel along at 60+. On the other hand, it’s a dirt road, so other folks are concerned about sliding and crashing, so they creep along. And the motorcycles go slowly (20mph) if they are Harleys, but fast (50+) if they are Yamahas.

Today a motorcycle stopped in front of my house, I couldn’t tell why, as he parked behind the roadside brush. I walked down to check it out, because typically people only stop on our road if they are littering large items or if they are talking to a pal coming the other way. But how much litter can a motorcycle do, right? He’s not dumping a couch or anything. I couldn’t see what he was up to before another car came, passed him and he left. Hubby assumes he was checking GPS, although there is no cell service here.


Anyyway, back to my point...
It’s interesting how vastly different are the speeds people take this road, and lucky that the traffic voolume is so low that they don’t run into each other while doing it.


...porch life.

 

[whollygoats]

Heh....Been doin' that for nigh on to forty years, now.

My porch is above a 'neighborhood feeder' street which meets a 'crosstown arterial' at the end of the block, all of it in the center of a major metropolitan area. When I started observing, near forty years back, there was only a flashing red light and a 30 mph posting. The street is wider than most neighborhood streets because it was built to accommodate streetcars on rails and the parallel 'crosstown arterial' is two blocks north, posted at 25 mph, grew to serve the major auto traffic. This meant that when the auto traffic on the parallel crosstown arterial backed up (like behind one of the regional buses), auto traffic would divert to my street and proceed to bomb from stop sign to flashing red at 35 mph or more. This was a bit complicated in that one of the city's high schools was at the eastern end of the street, and another high school was near the western end of the street, which facilitated a lot of unnecessary traffic travelling at unnecessary speeds (some of it clocked on radar units at 55+mph).

We don't have the benefit of a lot of distance from the street. For me, it is about ten feet down and about thirty plus feet out. So, traffic travelling at 55+mph up and down our neighborhood feeder was disconcerting.

Plus, it fed in to a traffic crossing issue. The intersection of my street with the other crosstown arterial, the north-south arterial, was a major accident site. Second worst in the whole metropolitan area. I would hear the accidents happening from my garden if I was outdoors in nice weather. That was excess traffic trying to cross a major north-south arterial to escape the congestion on the nearby east-west arterial. The north-south traffic was four lanes travelling at 40 mph and, from the south, coming up a rise which made the crossing invisible to drivers northbound. The meeting of the two was, in short, catastrophic.

The neighborhood did not like any of this. The problem was protracted because the east-west traffic was 'rush hour' traffic in and out of downtown to a set of major suburbs to the east. So it took fifteen years of planning, which culminated in a number of 'traffic calming' efforts. My street has a small 'traffic circle' (roundabout) 600 ft. west, a standard three-light traffic control at the intersection of my street and the N/S crosstown arterial less than 200 ft east, along with a traffic diverter which attempts to prevent through traffic, requiring turns off my street, and preventing turns on to my street from the N/S crosstown arterial, and reposting of the speed on my street to 25 mph.

It reduced the usage of the street. However, it did not reduce the speed. And, in the case where the traffic rounds the last traffic circle before the traffic control light at the crosstown arterial, which is 800 feet forward, much of the traffic romped on the accelerator in order to try to make it through the controlled intersection. An 800 foot drag strip. We asked for speed bumps; the city refused because they said the state standards prevented it.

Five years passed. Bicycles became a resurgent fad. It become tres trendy in my city. Guess what? My nice wide street was selected as a designated bicycle route. And, guess what else? Because the bicycle lobby complained about the excessive speed on the street, they installed speed bumps. And bicycle boxes at the nasty intersection, where the bicyclists get to go through, while all the motor traffic is required to turn on to the arterial.

Let me tell you, the best calming effort I have ever seen has been the designation of my street as a bicycle route. With scads of bicyclists, most motorists are hyper-aware and much more careful. The official speed on my street was recently reposted to 20 mph. This is being countered by more housing being built along the E/W crosstown arterial just to the north and, consequently, more congestion, which pushes drivers off of it and, in seeking out alternatives, they find my street.

Nowadays, it's not drivers, but parkers who are the perceived problem. The success of nearby merchants clogs the on-street parking nearby....

 

[Derec]

Well you need a differential for when the road has a curve.

 

[fast]

Whether it's 60 in the mud, 70 on pavement, 80 on sand, 90 on dirt, or 100 on loose rock, there's only one way to do it, and that's on a moonlit night with the headlights off and the emergency flashers on. As the darkness intermits with the glow of the heavenly body above, the wind shears inside the slightly downed window--down just enough to allow the rumble and roar soothe the beastly soul within. Oh yeah, music down low, baby by my side, and trees zooming by like a picket fence.

Safety is my game when she is near (I keep it under 130), but before the first kiss of the evening, while I was on my way, felony evasion is my name. A suped up V-8, straight shift, and positive traction.

There's only one way to do it, and i'm here to testify,

Fast

Yours truly,

fast

 

[Rhea]

Well you need a differential for when the road has a curve.

LOL. Math humor.

Although there is traffic humor there, too. A nearby street petitioned the state to get the speed limit lowered due to unsafe conditions from a curve. The state wrote back that the speed limit was fine and the curve was "a speed-limiting feature."

 

[Rhea]

Whether it's 60 in the mud, 70 on pavement, 80 on sand, 90 on dirt, or 100 on loose rock, there's only one way to do it, and that's on a moonlit night with the headlights off and the emergency flashers on. As the darkness intermits with the glow of the heavenly body above, the wind shears inside the slightly downed window--down just enough to allow the rumble and roar soothe the beastly soul within. Oh yeah, music down low, baby by my side, and trees zooming by like a picket fence.

Safety is my game when she is near (I keep it under 130), but before the first kiss of the evening, while I was on my way, felony evasion is my name. A suped up V-8, straight shift, and positive traction.

There's only one way to do it, and i'm here to testify,

Fast

Yours truly,

fast

On my street you really only want to do that in winter when reflections from the snow provide sufficient light. Because of overhanging trees, the moonlight is not enough to provide reliable visibility in the summer. But you will want to know the road pretty well, because in winter there are some durable icy spots, so you want to set up the corner with room to drift.

 

[bigfield]

Speed differentials at freeway onramps.

If the freeway speed limit is 100km/h, most vehicles on the freeway are going to be doing 100-115. Yet some drivers try to merge at less than 80km/h, during peak hour, which is just asking for a pile-up, especially since most drivers don't maintain a safe following distance.

Some of them get to the end of the merge lane, realise they have no chance of safely merging, and slam on the brakes. On the ramp. So I have found myself stuck on an onramp behind a queue of cars, at night in heavy rain, while each driver in the queue tries to merge--from a standing start--into heavy traffic around a panicked hatchback driver.

 

[bilby]

Speed differentials at freeway onramps.

If the freeway speed limit is 100km/h, most vehicles on the freeway are going to be doing 100-115. Yet some drivers try to merge at less than 80km/h, during peak hour, which is just asking for a pile-up, especially since most drivers don't maintain a safe following distance.

Some of them get to the end of the merge lane, realise they have no chance of safely merging, and slam on the brakes. On the ramp. So I have found myself stuck on an onramp behind a queue of cars, at night in heavy rain, while each driver in the queue tries to merge--from a standing start--into heavy traffic around a panicked hatchback driver.

It's worse in Queensland; Not only do the merging drivers try to join the road at 40kph less than the speed of the traffic; They also expect the freeway traffic to slow down to allow them to do this - and worse still, many of the drivers on the freeway actually do that.

So you end up with a traffic jam both on the on ramp and the freeway, with the associated risks of rear-end collision; AND the driver joining the freeway and the driver already on the freeway are each trying to give way to the other, leading to a situation like you get when passing another person in a corridor, where you both step one way, then both step the other, until the inevitable collision.

Someone needs to tell Queenslanders that you should not attempt give away your right of way, and that doing so is not so much 'polite' as it is 'lethally dangerous'.

 

[TV and credit cards]

Speed differentials at freeway onramps.

If the freeway speed limit is 100km/h, most vehicles on the freeway are going to be doing 100-115. Yet some drivers try to merge at less than 80km/h, during peak hour, which is just asking for a pile-up, especially since most drivers don't maintain a safe following distance.

Some of them get to the end of the merge lane, realise they have no chance of safely merging, and slam on the brakes. On the ramp. So I have found myself stuck on an onramp behind a queue of cars, at night in heavy rain, while each driver in the queue tries to merge--from a standing start--into heavy traffic around a panicked hatchback driver.

It's worse in Queensland; Not only do the merging drivers try to join the road at 40kph less than the speed of the traffic; They also expect the freeway traffic to slow down to allow them to do this - and worse still, many of the drivers on the freeway actually do that.

So you end up with a traffic jam both on the on ramp and the freeway, with the associated risks of rear-end collision; AND the driver joining the freeway and the driver already on the freeway are each trying to give way to the other, leading to a situation like you get when passing another person in a corridor, where you both step one way, then both step the other, until the inevitable collision.

Someone needs to tell Queenslanders that you should not attempt give away your right of way, and that doing so is not so much 'polite' as it is 'lethally dangerous'.

There should be a more extensive use of ramp meters. They look to be relatively inexpensive to install and do a wonderful job of maintaining traffic flow.

 

[bigfield]

Speed differentials at freeway onramps.

If the freeway speed limit is 100km/h, most vehicles on the freeway are going to be doing 100-115. Yet some drivers try to merge at less than 80km/h, during peak hour, which is just asking for a pile-up, especially since most drivers don't maintain a safe following distance.

Some of them get to the end of the merge lane, realise they have no chance of safely merging, and slam on the brakes. On the ramp. So I have found myself stuck on an onramp behind a queue of cars, at night in heavy rain, while each driver in the queue tries to merge--from a standing start--into heavy traffic around a panicked hatchback driver.

It's worse in Queensland; Not only do the merging drivers try to join the road at 40kph less than the speed of the traffic; They also expect the freeway traffic to slow down to allow them to do this - and worse still, many of the drivers on the freeway actually do that.

So you end up with a traffic jam both on the on ramp and the freeway, with the associated risks of rear-end collision; AND the driver joining the freeway and the driver already on the freeway are each trying to give way to the other, leading to a situation like you get when passing another person in a corridor, where you both step one way, then both step the other, until the inevitable collision.

Someone needs to tell Queenslanders that you should not attempt give away your right of way, and that doing so is not so much 'polite' as it is 'lethally dangerous'.

There should be a more extensive use of ramp meters. They look to be relatively inexpensive to install and do a wonderful job of maintaining traffic flow.

The freeway I use has no problem with congestion, even during peak hour. The problem is that some of the people who use it are incompetent drivers who can't safely use one of the safest fucking roads in the world.

Dickheads make traffic much worse than the traffic volumes necessitates: https://media.giphy.com/media/QikrdevEBjBZK/giphy.gif

 

[Derec]

Well you need a differential for when the road has a curve.

LOL. Math humor.

No, in this case, engineering humor.

 Differential (mechanical device)

But you are right, both involve curves.

Although there is traffic humor there, too. A nearby street petitioned the state to get the speed limit lowered due to unsafe conditions from a curve. The state wrote back that the speed limit was fine and the curve was "a speed-limiting feature."

Depends on the car, driver and conditions, of course.
But I have found that usually posted speed limits are way too low anyway, and are either chosen with cars from the 70s in mind or else are set such as to increase revenue.

 

[Derec]

There should be a more extensive use of ramp meters. They look to be relatively inexpensive to install and do a wonderful job of maintaining traffic flow.

They would not help with this problem, but likely make it even worse by forcing people to accelerate from dead stop from halfway down the ramp. If they are not capable or willing to accelerate to highway speeds
Around here these are only on during rush hours when the highway traffic is moving much more slowly than otherwise. They would be not only extremely annoying but also counterproductive otherwise.

 

[Rhea]

No, in this case, engineering humor.

 Differential (mechanical device)

But you are right, both involve curves.

To continue the humor, one doesn’t actually need a differential on a dirt road because the surface will permit the slip and hence a locked axle or even a spool is perfectly good.

But I have found that usually posted speed limits are way too low anyway, and are either chosen with cars from the 70s in mind or else are set such as to increase revenue.

In the case of our road - well, most of the streets in my town - the opposite is true because of our rural nature. My road includes a downhill, blind, off-camber, dirt, deeply ditched, true 90 degree corner with kittens and the speed limit is 55mph. People who don’t live in our town but driving through it often end up in ditches.

We’ve had two on our property (much gentler curve than the one above, but with a little down-force-pausing hump), failing to set up the turn and sliding off into the creek. One ended up upside-down bridged over the creek at 2am. But he was drunk, so he just went to sleep there on the ceiling of his car until the paper carrier noticed him at about 5am. We woke up to the engine sounds of the fire truck. No sirens because there are no cars to warn or anything, just that big engine noise and the lights. He turned out to be fine, I think.

Speed-limitiing feature.

But more seriously, I find that most speed limits are good for poor drivers and snow-storms, so they have their uses.

 

[bilby]

Although there is traffic humor there, too. A nearby street petitioned the state to get the speed limit lowered due to unsafe conditions from a curve. The state wrote back that the speed limit was fine and the curve was "a speed-limiting feature."

Depends on the car, driver and conditions, of course.
But I have found that usually posted speed limits are way too low anyway, and are either chosen with cars from the 70s in mind or else are set such as to increase revenue.

Around here speed limits appear to have been set with cars from the 50s in mind, and are safe speeds if driving in the wet, with drum brakes and cross-ply tyres.

It rarely rains here. And when it does, all the drivers lose their fucking minds and start driving into each other regardless of the speed limits.

Although it doesn't help that the Queensland government appears to have commissioned a special paint for road markings that is formulated to disappear completely when wet.

 

[spikepipsqueak]

Although there is traffic humor there, too. A nearby street petitioned the state to get the speed limit lowered due to unsafe conditions from a curve. The state wrote back that the speed limit was fine and the curve was "a speed-limiting feature."

Depends on the car, driver and conditions, of course.
But I have found that usually posted speed limits are way too low anyway, and are either chosen with cars from the 70s in mind or else are set such as to increase revenue.

Around here speed limits appear to have been set with cars from the 50s in mind, and are safe speeds if driving in the wet, with drum brakes and cross-ply tyres.

It rarely rains here. And when it does, all the drivers lose their fucking minds and start driving into each other regardless of the speed limits.

Although it doesn't help that the Queensland government appears to have commissioned a special paint for road markings that is formulated to disappear completely when wet.

They're encouraging us to make use of our other senses.

That same paint becomes very slippery, so you can judge the position of line markings by where your tyres lose traction.

 

[Jimmy Higgins]

Although there is traffic humor there, too. A nearby street petitioned the state to get the speed limit lowered due to unsafe conditions from a curve. The state wrote back that the speed limit was fine and the curve was "a speed-limiting feature."

Depends on the car, driver and conditions, of course.
But I have found that usually posted speed limits are way too low anyway, and are either chosen with cars from the 70s in mind or else are set such as to increase revenue.

Around here speed limits appear to have been set with cars from the 50s in mind, and are safe speeds if driving in the wet, with drum brakes and cross-ply tyres.

It rarely rains here. And when it does, all the drivers lose their fucking minds and start driving into each other regardless of the speed limits.

Although it doesn't help that the Queensland government appears to have commissioned a special paint for road markings that is formulated to disappear completely when wet.

Must be a product from Ohio. You drive on I-80 in PA and it is raining, you can see the lines clearly, literally can tell when you cross the state border into Ohio because you can no longer see the lines. WTF?!

 

[Worldtraveller]

Whether it's 60 in the mud, 70 on pavement, 80 on sand, 90 on dirt, or 100 on loose rock, there's only one way to do it, and that's on a moonlit night with the headlights off and the emergency flashers on. As the darkness intermits with the glow of the heavenly body above, the wind shears inside the slightly downed window--down just enough to allow the rumble and roar soothe the beastly soul within. Oh yeah, music down low, baby by my side, and trees zooming by like a picket fence.

Safety is my game when she is near (I keep it under 130), but before the first kiss of the evening, while I was on my way, felony evasion is my name. A suped up V-8, straight shift, and positive traction.

There's only one way to do it, and i'm here to testify,

Fast

Yours truly,

fast

Too many wheels.

165 mph indicated on two wheels is way more fun.

95, leaned over dragging knee is even better.