Traffic Circles/Roundabouts?

[Happy Gilmore]

We have plenty of them in Massachusetts

 

[Bird]

Tons of them in New Jersey, the state with the most people per sq. mile! They work this way, if you have an old car and or no insurance, enter at maximum speed, do NOT yield. If you are in the circle and you have a new car and or insurance you yield to the idiot in the old car. Got it??! Great idea in 1925, not so in 2014.

:laughing:Obviously, they work in some places, but I think everyone was glad to see Dallas get rid of the traffic circle on Harry Hines Blvd at Northwest Hwy many years ago. I did work some interesting wrecks there in the mid-60s.:laughing:

 

[dave1949]

Are roundabouts safer for motorcycles? I don't do rolling stops, mainly because I don't trust myself to quickly pick up an on-coming motorcycle visually.

When you are the biker, you always wonder if the person at an intersection sees you; what they may do is anyone's guess. Are traffic circles a bit more predictable, and is there more "escape" room?

 

[3930dave]

Are roundabouts safer for motorcycles? I don't do rolling stops, mainly because I don't trust myself to quickly pick up an on-coming motorcycle visually.

When you are the biker, you always wonder if the person at an intersection sees you; what they may do is anyone's guess. Are traffic circles a bit more predictable, and is there more "escape" room?

Great question.

On 4 wheels, I generally like the roundabouts that have gone in here, with the same caveats about size/area needed, and limitations on volume handling already cited.

#1 Rule for Surviving Street Riding of motorcycles - assume that No motorist sees you. I wear a safety (high-visibility) vest when I ride, and usually always have my high-beam headlight on during the day - but I still remind myself about #1 every time I fire up the bike.

The wildcard that a roundabout adds here is getting a driver that doesn't understand what they are/how to use them, and may drive erractically in them - but that isn't just a roundabout issue, now is it ?

Specific to street bikes, what I do like about roundabouts is that it pretty much removes the dreaded (sometimes lethal) typical street bike accident where the bike is going straight through on a green, and a facing vehicle decides to turn left in front of the bike.

Years ago I was bicycling through a green light, and a facing car turned left in front of me in that exact manner. I managed to brake hard, have the bike go under the right front of the car, while I sailed over the hood - broke my fall by skidding along on the palm of my left hand (taught me to wear gloves), and the left side of my face. Then, and esp. now, I considered myself lucky to literally walk away, with nothing but severe road-rash, and sore muscles.

That bike accident was in the daytime, and the guy admitted to the LEO that he "just didn't see me" - he was pretty upset, as he himself had been hit on a bicycle in the same manner.

As a rider, I'll trade off getting squeezed over to the shoulder of a lane in a roundabout vs. the Left Turn T-bone at a traffic-light controlled intersection anyday, so I'll give roundabouts a personal thumbs-up for 2 wheels :thumbsup:.

Rgds, D.

 

[3930dave]

The finest example of roundabout engineering I know of, in this fine nation, is this effort in Swindon...

I was thinking.... When Graphic Artists Go Bad ! ......

Neat picture. Just hope no civil engineers over here get any ideas from your post !

Rgds, D.

 

[3930dave]

Roundabouts above a certain traffic volume are inefficient and the traffic lights beat them. In hamilton new zealand we went from traffic lights on 2 major intersection in 2004/2005 to roundabouts and then eight years later ripped the roundabouts out and put traffic lights back in and sped traffic up. The problem was in 8 years the traffic had more than doubled.
Each change ment months of disruption and cost millions$ per intersection and a lot of pissed of people . It felt like the engineers hijacked the council.
Round abouts have worked in low and medium volume with mainly car traffic.
Mixing trucks with cars clogs things up fast as truck have to go slower, see the link to the tanker rollover. Roubabout camber is critical for truck ESPESIALLY when you have a liquid load.
Engineers often don't have a truck lisence so will design a roundabout to cause a rollover (SH1 southbound out of hamilton , 3yrs to fix) or taupo haevy vehicle bypass(roundabout so tight that heavy haulers couldn't get onto bypass without running of the road, so had to go through town,) the bypass was ment to take trucks out of town.

While I have a lot of respect for good engineering, your comment reminds me of a line a guy I worked with liked to use....

"Last year I couldn't spell Enginear, now I are one !".

While there is no substitute for actually building something and using it, today it's hard to imagine that even basic modelling software couldn't have prevented the heavy truck problems you cite.

Latest thing here for some overpasses/interchanges near Toronto - renovations to handle dual 53' trailers, something we are starting to see more of. I'd hate to see one of those dual 53s, off track and going through a small roundabout !

Rgds, D.

 

[kc5dlo]

:laughing:Obviously, they work in some places, but I think everyone was glad to see Dallas get rid of the traffic circle on Harry Hines Blvd at Northwest Hwy many years ago. I did work some interesting wrecks there in the mid-60s.:laughing:

That is the one I always think of but I was too young to remember the details of why it was so dangerous. I remember it was very large in diameter. Must have had multiple lanes and that probably is part of its problems. I am seeing them show up in neighborhoods now and they seem to be working well.

 

[vtsnowedin]

I don't see the advantage over a 4 way stop. You are suppose to stop before entering anyways. I'm partial to just 4 way stop with flashing red light. But they have them in Ocala and Gainesville FL. Both between 50-100k people. Always where a 3 or 4 way stop used to be, never a real intersection.

I don't know about the ones you have but here the entrances are marked with yield signs not stops. If built right without sight obstructions in the center you can see the cars coming around and adjust your approach speed to slide into an open slot without stopping or clashing with them. Sort of like gears meshing in a well synced transmission.

 

[tkappeler]

NJ had tons. Lots of accidents. Most have been replaced, thank goodness. They only seen to work well in low volume areas.

 

[paulharvey]

I don't know about the ones you have but here the entrances are marked with yield signs not stops. If built right without sight obstructions in the center you can see the cars coming around and adjust your approach speed to slide into an open slot without stopping or clashing with them. Sort of like gears meshing in a well synced transmission.

They have yield signs here, but they are designed where you Tee up with them, with curb and all, so you basically have to rolling stop at best to not jump the curbs. That's in just a SWB F150. They don't have them really shaped right where you can slow a bit and go.

 

[tkappeler]

I don't know about the ones you have but here the entrances are marked with yield signs not stops. If built right without sight obstructions in the center you can see the cars coming around and adjust your approach speed to slide into an open slot without stopping or clashing with them. Sort of like gears meshing in a well synced transmission.

:laughing: That's a good one. Well synced transmission. That does not work in NJ! It's always "me first" and you can't have everyone be first.

 

[dmccarty]

With my apologies to Aggie graduates, was that project designed by Texas A&M civil engineers?

Steve

Nah, that "intersection" had to be designed by a NC State graduate. :laughing::laughing::laughing:

<Sigh> I wish EE Bota was still with us so I could get his goat. <EndSigh>

Later,
Dan

 

[tcreeley]

I grew up with rotaries or traffic circles in Mass.. Dangerous- accidents with all of the merging and criss-crossing. I don't like them. Maine has just started to build them- too small.

 

[vtsnowedin]

There is a difference between old style rotaries and traffic circles and the newer Roundabouts they are building today. Mostly it is the size of the center circle. Old style was often a hundred feet or more in diameter and new roundabout is fifty or less. Except for being a pain in the ***** to plow the new style seems to work pretty well and save a lot of gas in cars that would have had to stop for a red light and wait their turn. Bring in more then one lane from each direction though and they get quite harry and the local body shops best friend. When they get anti collision auto drive on all cars that work in a roundabout it will be a great thing if we still have gas to drive with then.

 

[mrmikey]

They're not bad as long as people realize who does/doesn't have the right of way. When they first came around here I cursed them, now I think they're great....Mike

 

[redman135]

3930dave, in australia on roadtrain (2-4 trailers) routes through towns ,they have a raised concrete dome (painted for visibility) so the road trains can drive over it .1st trailer goes round 2nd cuts in 3rd & 4th trailers go over part or all of centre dome. The trailers are 15m long. As long as your engineers learn from australian experiance they should be ok. Lastly remember a truck with a long trailer often needs to turn from the opposite lane, ie turn left from right lane as trailer will cut in to the left lane on smaller roundabouts. If you use the left lane left turn approach you have trailer tracks in the centre lawn/garden,and a lot of mud on the road ,oops.

 

[jaotguy]

As long as your engineers learn from australian experiance they should be ok.

up here , they definitely didn't ....

the original round abouts were small , flat and out in the country and low speeds .... you approached, saw what was coming in all directions, adjusted your speed to suit and went round ....


here they build a multi lane unit ... raised center with "pretty trees , shrubs. and signs" in the middle to block the view of the area, then put in the pedestrian cross walks a short distance away..... then wonder why they have more accidents and don't work as well as the European ones ....

 

[reb]

:laughing:Obviously, they work in some places, but I think everyone was glad to see Dallas get rid of the traffic circle on Harry Hines Blvd at Northwest Hwy many years ago. I did work some interesting wrecks there in the mid-60s.:laughing:

I think that is the one I encountered the first day when I moved to Dallas 40+ years ago. I was concerned about navigating it so I would not get lost, so I counted the turnoffs as I went around so I could find my way back if the road I took didn't work out. A good idea, except that I assumed it was a four road intersection. I found out after a couple of tries that there were five exits.:laughing:

 

[boggen]

KISS (keep it simply stupid) *raises fist in anger* *arghs*

i understand as cities get larger and more traffic occurs, you need more lanes, etc....
prefer if they would just make ever other road a one way streets, and turn "individual blocks" like a huge round about.

 

[Bird]

I think that is the one I encountered the first day when I moved to Dallas 40+ years ago. I was concerned about navigating it so I would not get lost, so I counted the turnoffs as I went around so I could find my way back if the road I took didn't work out. A good idea, except that I assumed it was a four road intersection. I found out after a couple of tries that there were five exits.:laughing:

Yeah, and that huge mound of dirt in the middle didn't allow you to see all the traffic, the entrances and exits as you entered the circle. And I wonder how many people ever saw what was in the middle. I'd been driving around that circle for years without ever seeing what was in the middle until one night, probably 2 to 3 o'clock in the morning, when I got a call on an accident at the circle. I drove up there and around the circle twice; not a single vehicle or person in sight anywhere. The dispatcher had no information on the caller; just that there was an accident at the circle. As I slowly went around the circle again, I happened to notice a utility pole at the inner edge of the circle that didn't look right, so I got out for a closer look. I soon learned that the "mound" of dirt only a berm all the way around the inner edge of the circle. It was like a bowl in the middle, and there was a Plymouth upside down right in the middle. It was soon quite clear that he had been northbound on Hines at a high rate of speed, hit the curb, became airborne, went through the utility pole about 6 feet in the air, and landed upside down in the middle. I assume the driver was not injured, or at least not seriously, because there was no one in or around that car. But he had hit that utility pole, completely shattering it, and the wires had obviously caused it to settle back in place so that it wasn't readily apparent that the pole had been struck.