Cindy, What's the deal with left turns?

[gfretwell]

In Grand Rapids they pretty much eliminated left turns. Ta all major intersections you have to go a half a block down, make a U turn and come back for a right. I suppose it does make the light cycle shorter.

[Thomas]

Maybe they are trying to eliminate would-be successful Nascar drivers

[Dean Hoffman]

People in Grand Rapids are too poor to afford roundabouts.

[Wade Garrett]

Yeah, when I lived in Michigan in the 70's, they had a lot of those on major divided surface streets. I thought they were stupid.

Also seen then in south Florida- Broward county.

I couldn't stand Michigan drivers. They usually drove 5 MPH under the speed limit (virtue-signalling, no doubt) and when you zoomed around to pass them, they'd shake their fist at you as you zipped by.

[angelica...]

We call that a "Michigan left turn". On a divided roadway with a median, it enables traffic to flow better.

Cindy Hamilton

[angelica...]

Really? In my experience it's more customary to drive 10 over. And passing on the right is what you do when some moron is doing the speed limit in the left lane.

Cindy Hamilton

[Neill Massello]

[Wade Garrett]

This was back in the early 70's- and most of my driving then was on two lane secondary roads.

[micky]

In New Jersey they have a few "jug handles". You veer to the right before the interesection and go into the cross street so you cross the street you were on when the light changes.

I haven't seen them elsewhere.

I don't like traffic circles. They eliminate lights but they cause you to slow down.

[Ed Pawlowski]

I've seen jug handles in a few places in PA but nothing like NJ. Circles (roundabouts) are becoming more popular all over too. Only a few here in FL but my sister lives in Pinehurst NC. Evidently they had a sale on them as there are dozens and dozens it seems.

How about a Diverging Diamond? It actually works well. I pass through here a couple of times a month and the flow is smooth even where it is 5 or 6 lanes across.

How it works

[Jim Joyce]

I didn't know it was called a Diverging Diamond, but we have one of those just a few miles from where I live. We pass through there to reach most of the shopping areas. It felt odd at first, but we quickly got used to it. We also have traffic circles and those work fine, as well. No jug handles or Michigan left turns around here, although I've seen those in NJ and MI.

[Mark Lloyd]

[snip]

There used to be a traffic circle around here. Now it's a complicated multi-way intersection. When it was a circle, there was a common problem of trucks falling over because they didn't slow down enough.

[gfretwell]

you end up with lights moderating the traffic going into the circle. DC is full of them and they had to tunnel under some of them. They all have lights. Auckland New Zealand has the same problem with theirs. They don't have lights on the circle, they have them on the roads feeding the circles. The effect is the same tho. You are sitting at a light waiting your turn to enter the roundabout.

[Marilyn Manson]

They installed traffic circles near me and I couldn't be happier. The road is the last few miles of an interstate that ends at a lake. The section used to be a 55 MPH, 4 lane highway with 4 traffic signals. It was fine for the really short "rush hours" we have around here, but at any other time of the day the road is never really busy and drivers would sit at a red light and not see another car during the entire cycle. The entrances to my neighborhood are at 2 of those intersections, so I drive that stretch of road multiple times daily. The lights were a PITA.

Worse yet, specifically because the road is often empty, cars and motorcycles would occasionally drag race *hoping* to catch the lights perfectly. It didn't always work out that way and racers have caused serious accidents, lost control and ended up in people's yards and generally created unsafe and noisy conditions.

They removed the straight highway and built a curvy road, one lane in each direction with a wide grass covered medium. The 4 traffic signals were replaced with roundabouts and the entrance to the roundabouts were placed so that even if there isn't another car around, you really have to slow to the 15 or 20 MPH speed limit assigned to each roundabout. The maximum speed on the entire stretch is 45 MPH, but there's really no room between the roundabouts to reach that speed, so 30-35 is usually the max obtained.

They added sidewalks on both sides of the road and it's actually a pleasure to walk down to the lake now that traffic has slowed. No more noise and no more high speed accidents.

[angelica...]

I'm surprised they didn't install sensor controls long before the current fad for traffic circles.

If your road genuinely doesn't go anywhere but to the lake, this certainly is the best solution.

Here, they installed a traffic circle where two high-volume roads meet. The accident rate has gone up, but the severity has gone down.

It's not too bad on weekdays, where most drivers are accustomed to the circle. But the weekend warriors are a little spotty on their technique.

Cindy Hamilton

[Marilyn Manson]

The DOT built a Diverging Diamond in a nearby city a few years ago. Like JJ said, they feel odd at first, but they really improve traffic flow, especially at the on and off ramps of a highway.

The blue and green denote a pretty heavily trafficked surface road that passes under a highway.