As I was awaiting my turn to dart across three lanes of speeding traffic today a question occured to me. Are certain types of intersections safer than others? I remember while visiting Michigan (near the Detroit area) noticing that in a great deal of their intersections, you aren’t permitted to turn left. Instead, you have to proceed through the intersection, make a U-turn just after the light, and then turn right on the street you desire. Although this seems like a waste of time, especially when the traffic is low, it does seem like it would be safer.
During my recent trip to London, I saw that they use “roundabouts,” which for the uninitiated are basically big circles in the road on which you enter on one side and proceed around the arc until you get off on your desired street.
Here in the Dallas area we have the standard (at least, standard to me) intersections, most of which either provide a green arrow for a protected left turn, or more often just a green light where you’re supposed to yield to oncoming cars, and turn left whenever there’s a break in the flow. We’re also proud owners of three of the ten most dangerous intersections in the country (according to State Farm).
While I do get perverse joy in cheating death while going to the bookstore nearby, I wonder if I’m doing so needlessly. Are these other types of intersections proving to be successful?
Having live in all three circumstances you’ve mentioned (MI, TX and MA-where the rotary is still in use) in my opinion the MI U-turn is the safest.
In my experience the TX standard left turn tends to not only back up traffic, because the left turn lanes are NEVER long enough and end up blocking the through lanes, but because they also force folks to move into the middle of the intersection at the green waiting for lights to change.
The rotary is just plain the work of the devil. Despite the fact that folks ON the rotary have the right of way, they almost always yield to traffic entering the rotary. Then you have to try to get to the outside lane to make your turn without dying. Rotaries are just plain evil.
The MI U-turn seems to be the quickest, safest way to keep traffic flowing except when you have to cut across five lanes of heavy traffic to turn right. Good acceleration is a must when you live in metro Detroit.
There’s also the jughandle, common in Jersey. To make a left, you go to the right, where there is a little loop that takes you to the intersection so you can go straight across. These are useful for when a little street crosses a big street, as no one on the big street has to make a left turn.
I was driving around Western Michigan last week and I noticed that a lot of the left turn signals there are flashing red lights, which took me a while to get used to.
Also the signals in that part of Michigan tend to be hung from wires above the street and for someone who is tall and sits with his head close to the head liner of the car, you have to really contort yourself sometime to see the signal.
I did notice the Michigan U-turn as described in the OP in Grand Rapids, especially on a busy street like Belt Line Rd.
There’s a difference between a round-about and a rotary. Charleston has successfully implemented a round-about and it has worked very well. The rotary is the circle thing that was described above as a round-about, where cars enter the circle and get off at the desired street. In a round-about, a street’s intersection contains a circle and cars on the subsidiary side street, perpendicular to the main street, enter the circle and can continue on the other side, after traversing half a circle. In the meantime, drivers on the main street just make a slight half-circle arc and continue on their merry way. The round-about is smaller than a rotary.
Round-a-bouts are becoming a big thing in Colorado (and, Slacker, we have three of the top 10 bad intersections here, too.
I have heard the round-a-bouts (round-abouts?) described as far safer than even intersections protected by lights. I don’t have any problem with the ones I have used.
Jughandles? I’m afraid I can’t picture them in my mind. Any pictures anywhere?
Straight ahear, u-turn and turn right? Sounds weird to me.
From what I remember from transportation engineering class:
The standard 90 degree-4 way intersection is the safest. The reason for this is that when the angle is higher, it is more dificult to check for trafic on one side. You need to turn your head more and there is a greater chance that something is in your blinf spot.
I cant see how rotaries or roundabouts are safer. They usually require merging onto trafic that speeding around in a circle and are generally confusing and a pain in the ass. Which usually translates to drivers making poor judgements. Generally, keeping things simple is best.
Having lived in Boston for awhile, I have decided that the following intersection configurations suck:
The 5 way major intersection with a T-track (painfully slow light rail) crossing across the intersection and down the middle of one of the streets.
A major street that abruptly ends in a maze of 1-way streets so that you cant return the way you came.
*A cloverleaf on a major highway. This causes decelerating cars exiting the highway to cross paths with accelerating vehicles entering the highway. At the Rt128/Rt9 exit, Rt128 also abruptly narrows from 4 lanes to 3. At the most businesst times, you can also drive on the shoulder as an extra lane.
In Australia, roundabouts have become commonplace in the last fifteen years. I don’t have any hard data, but my experience is that they are indeed safer than a “regular” intersection. There was some confusion when they were new because motorists weren’t familiar with them, but I think that although maybe they haven’t reduced the number of accidents, they have reduced injuries simply because all vehicles (from every direction) are forced to slow down before entering one.
Is a jughandle anything like a hook turn? In Melbourne, we have trams that travel down the centre of the road. To stop them being delayed by right-turning vehicles, the vehicle has to move over to the left hand side of the road and wait until the coast is clear to cut across traffic. The sign used to indicate these turns could conceivably seen as a jug handle. n
Interesting question, but not wholly unambiguous. It all depends on how you define safe.
It could mean “lowest number of collisions”, “lowest number of collisions involving injury” or “lowest number of deaths”. In Sweden, where I used to live, there has lately been a huge concentration on the number of deaths in traffic. (It is already pretty good, typically around 600 per year, with a population of 9M. - Compare that to the US figure of 41,471 for 1998)
The theory used to combat traffic deaths has been to reduce the speed with which cars can collide, rather than eliminate the possibility of collisions, which would probably be impossible. Most modern cars are safe enough that you would survive a head-on collision at over 50km/h (30mph), but probably not a side collision at the same speed. Therefore lots of work has gone into elimination of possible side-on collisions, which is indeed the main problem with the type of left turn described in the OP, as well as in the MI U-turn. Some pinhead in the Swedish Road Administration decided that roundabouts are the safest, as you are unlikely to be hit at a very high speed.
In my home-town they have replaced many of the big intersections with massive (~50m diameter) roundabouts. The traffic intensity is not too big, and the traffic flows very well.
Thus I believe that one answer to the OP would be that roundabouts are indeed safer, in that they reduce the speed so much that you are likely to survive any collision likely to occur.
One could also argue that the safest way to improve US road safety would be to let all the merkins go through a European style driving school. There is a HUGE difference in traffic fatalities between US and EU.
Roundabouts in the UK used to be fairly simple; as described above, it was just a circle which you drove around, the only rule was that you gave way to traffic from the left (that would be the right in America) - i.e. you yield to traffic already on the roundabout, this works quite well because traffic coming off the roundabout and into the road where you’re coming out affords you the opportunity to pull out, so it’s a kind of self-regualting thing.
But they are now increasingly complicated (and some would say cocked-up) by the inclusion of traffic lights and changes to the right-of-way priorities, thus they lose their function as a way to keep the traffic moving and gain a sort of packet-switching/buffering function.
I’m not really seeing the advantages of the U-turn intersections. If cars turning left would back up traffic, why wouldn’t they do the same trying to make a U-turn?
When we were driving around England in the early 80s, we actually liked the roundabouts because we could just keep going around in circles until we had a chance to examine the map and figure out exactly which spoke to take. I don’t remember them being to crowded though, so maybe that’s the difference.
It is interesting to note that many of the most dangerous intersections, from the State Farm list, are standard DOT intersections where two multi-lane roads cross. In “Suburban Nation” by Duany and Plater-Zybeck, they note that these intersections are dangerous because they allow (and encourage to some extent) people to go fast. Wide lanes and large radius corners all contribute to the impression that you can go through them at 45 MPH (or faster). They found that intersections that are confusing cause people to slow down and pay attention, and that makes them safer. They use as an example an intersection in Florida of five roads and two train lines that, despite what the DOT engineers have been trained to expect, has one of the lowest accident rates in the state.
Personally, I like rotaries - if they are used correctly. In New Jersey people seem to have no clue - they would come up to it, STOP and WAIT, and then finally go from a dead stop. Might as well have put a stop sign there. In Boston my experience is that you don’t stop unless you really have to, and that keeps things moving. I recall clearly one winter day driving with my uncle through, I think, Fresh Pond Rotary, in a Volvo with fogged over rear windows. Little visibility, gloomy day, and he just slips it into the traffic and pops out at his street, no muss, no fuss. Maybe Boston drivers are forgetting how to do that - I sure hope not.
[Hijack]
Which is why all of the Germans cut curves when driving down twisty little highways. I have at least one brush with death a week thanks to this kind of thing during my daily commute from Meisenheim, Germany to Wiesbaden, Germany to go to work. What I am seeing is no exception to the rule, either. The white line down the middle of the roads here all ways wears out first in the curves.
If European driving schools teach you to cut curves, then I will just stick to what I taught my self while driving a one ton truck down gravel roads in the farm country of southwest Missouri.
[/Hijack]
While I cannot speak about the safety of it… roundabouts rule!
I recently drove for the first time in the UK and found that roundabouts are excellent for keeping the traffic moving and seem completly safe when the people using them are doing so correctly. This I have no worries of, since the standard of driving over there is CONSIDERABLY better than here in Canada.
I love driving… I would even say it’s a hobby… but the area where I live (just East of Toronto) has recently installed so many traffic lights that it makes going out in your car a painful and frustrating experience… there is one main road where a stretch of road about one kilometre long has 7 (yes seven) sets of lights…
I see more and more people pushing to make it through the yellow lights… I can hardly blame them when they have to drive on roads like that… roundabouts would save a great deal of time, fuel, polution, frustration and no doubt, lives…
If you look at metrics which accurately reflect the differences between driving cultures (like US or Australia) and non-driving cultures* (like France or Germany) the differences in fatality rates tell a completely different story.
Granted, as far as raw numbers go, there are more deaths per 100,000 population in the US than in Sweden (15.3 vs. 6.6 as of 1999) but that doesn’t tell the whole story. In a typical year, a US driver travels about 67 times as far as the average Swedish driver. When you compare the number of deaths with the number of miles driven, the fatality rates are quite comparable (8.3 for Sweden, 9.6 for the US). Let’s compare the US with other European nations (particularly the safe Scandanavian nations) as you suggested. You’ll see from the data that the US is on par with the safest nations in Europe and fares far better than most. Perhaps they will send their drivers to school on this side of the pond.
In the New Orleans metropolitan area, proud owners of intersection #9 on the State Farm list (Veterans Blvd. and Clearview Pkwy.), I believe part of the problem is the fact that while streets in the city are in such bad shape (VERY old, in other words), the streets in the suburbs are nice and smooth. Thus when people get out onto a big street like Veterans they think they can go as fast as they want.
Veterans and Clearview is an interesting intersection. Two-way traffic meets two-way traffic, only because of one of New Orleans’ quirks, the neutral ground (read: median) on Veterans is especially large, while on Clearview it’s undivided traffic–just the double yellow line. To top it off, Clearview is pretty much the exit ramp of a big cloverleaf over I-10, which runs parallel to Veterans. So everyone coming off of the interstate at Clearview has to go through that intersection. At that intersection you can’t turn left either; you have to go through and U-turn.
At Causeway Blvd., parallel to Clearview about a mile away, they had the same problem, only worse, because there’s a big shopping mall right on the corner. So they had to build an overpass over the whole thing. But people that want to go left still have to do the U-turn.
Now that I’ve sufficiently drowned this post with too much detail, my point is that I prefer the U-turn rule simply because it keeps traffic moving. Especially when there isn’t room for a turning lane.
