4-way stops vs. roundabouts: which is more efficient? Mythbusters tests both (vid)

[320touring]

Originally Posted by jeff88

320touring, that's why, although roundabouts are effective at times, I prefer overpasses with auxillary roads. The only traffic congestion possibility is where you merge onto the next E-way, but the auxillary road is usually long enough to not effect the traffic on the first e-way if the line to merge gets too long.

I'll post a screenshot of the two expressways I'm talking about like you did as soon as I get home.

We have some similar situations here, although we're a touch shorter on land than you lot

there's no magic bullet though, unless of course drivers actually paid attention..

[user removed]

When I started driving here, there were "traffic circles" which were two lane roundabouts. They are nothing new as that was 45 years ago. As far as overpasses, they are much better for limited access roads with much higher traffic volume. The two lanes entering the Hampton Roads Bridge Tunnel can see 86,000 vehicles in 24 hours, on just the eastbound 2 lanes.
At 420 cars in 15 minutes, obviously a roundabout would never work for that kind of traffic volume. On US1 in the Florida Keys, I have watched people wait 15 minutes to make a left turn in very heavy traffic with no lights to break the flow. I would just go right and make a u-turn shortly after.
On my typical drive, which involves 46 lights in 40 miles, they could eliminate half of them and make those roads right turn only. At least they are decently timed, even though you have to go 3-5 over the limit to stay in the timing "sweet spot".

regards
Mech

[XYZ]

Originally Posted by 320touring

Roundabouts can be damn effective-but that relies on the people using it correctly

Around here the biggest problem is that people don't understand what a "YIELD" sign means. Some think it means "stop". And some don't stop even when stopping is necessary. That tends to render the roundabout (AKA traffic circle) ineffective.

[mechman600]

They are adding roundabouts all over the place around here. I like them.

Around here, ICBC, our public insurance company (monopoly), has a large say in road planning. I am told that traffic flow is less of a reason to use roundabouts than insurance reasons. It is far easier to determine who is at fault in an accident in a roundabout. Whoever is IN the roundabout when it happens is not guilty. Four way stop accidents are often less black and white.

[bestclimb]

Originally Posted by darcane

In Anchorage, AK, they have timed lights and the prevailing traffic heads one direction through many intersections (basically, N-S south of downtown and E-W east of downtown). Because of this, they time the lights so you hit green lights at every intersection as you go through the city along the primary route. This works very well (probably even better than roundabouts)... until you try to take one of the side streets.

5th ave rocks.

the AK drivers in roundabouts on the other hand...no really you don't have to stop to let me in, or stop for the guy who is, like you, just about to enter the round about.

[jeff88]

Here's the "intersection" I was talking about. I think (from seeing it in action) this is the best option to eliminate intersecting traffic as much as possible. Both Almaden Expressway and Capitol E./Hillsdale Ave. are high traffic streets that don't see a lot of back-up from this intersection. It takes a lot more construction-wise to do this, but it alleviates congestion quite well. There are a lot of spots that have two routes onto the next expressway, not really sure why, but they help in traffic congestion (or lack thereof).

The pic might be small, see attachment:


Dark Green: Capitol, West to Almaden, South
Light Green: Almaden, South to Capitol, West
Red: Hillsdale, East to Almaden, South
Orange: Almaden, South to Hillsdale, East
Dark Blue: Almaden, North to Capitol, East
Light Blue: Capitol, East to Almaden, North
Purple: Capitol, West to Almaden, North
Pink: Almaden, North to Capitol, West

[euromodder]

Originally Posted by jeff88

I like overpasses. Then to transfer roads, there are auxillary roads to exit one and merge onto the other
The nice thing about the auxillary roads is they give you a good excuse to have an office building or restaurant or similar.

Over/underpasses work well, if you have ample space for them.
Space tends to be more of a premium in Europe

On the local ring road, we're going from a pretty congested, totally unsafe traffic light controlled crossing, to a situation where 1 lane either way in an underpass has to cope with all thru traffic (halving the thru lanes), while local + in/outbound traffic uses a roundabout @ ground level.
I'm wondering wether that'll improve things.

Originally Posted by t vago

Nope, definitely was OpenDNS.
I'm now using OpenNIC.

Weird, as it worked instantly for me.
The whole idea of using OpenDNS was not having gov't mandated or whatever filtering.
I've added OpenNIC DNS to my list - now using OpenNIC, OpenDNS, Google, and my ISP in that order.

[t vago]

Originally Posted by euromodder

Weird, as it worked instantly for me.
The whole idea of using OpenDNS was not having gov't mandated or whatever filtering.

Tell me about it. Imagine wanting to look at the video at the start of this thread, to see whether the MythBusters crew would goof up their test procedures to the point where the test itself would be invalid, and getting that blasted "Daddy knows best" webpage instead of the YouTube video. I was not happy, that's for sure.

[jamesqf]

Originally Posted by euromodder

Over/underpasses work well, if you have ample space for them.
Space tends to be more of a premium in Europe

It's not just space, it's money. Look at the cost to construct an over/underpass, versus a roundabout.

[MetroMPG]

A funny thing: my brother is the municipal civil engineer where I live. He's the guy who decides on things like traffic lights vs. traffic circles. He hasn't put in one in 25 years. We've talked about it. Part of the problem is we have an unusually high concentration of seniors who don't like/adapt well to change (my take, not his). Another issue (already mentioned) is roundabouts require more space. Another is they complicate snow removal.

Yet in the closest neighbouring small city, their engineer has been adding them regularly in the last 10 years or so, mostly on major roads.