Why do traffic accidents occur frequently though it is a good intersection?

byOscar Nilsson

Government issuedStatistics on road trafficAccording to the accident during riding a bicycle, the number of deaths caused by accidents in November 2017 was 436, down 2.7% from the previous year. Although the number of death accidents while cycling passengers decreases year by year, a certain number of accidents occur every year, especially in complex intersections with poor looks and large curves that tend to speed, where frequent accidents occur There are signboards etc. that let you know that it is. Such intersections exist not only in Japan but all over the world, and about the "intersection where many traffic accidents occur frequently" in the UK,singletrackworld.comHas posted considerations and remains in the eye of many cyclists.

»Updated: Collision Course: Why This Type Of Road Junction Will Keep Killing Cyclists
http://singletrackworld.com/2018/01/collision-course-why-this-type-of-road-junction-will-keep-killing-cyclists/

The Ipley intersection near Southampton in England is where the two roads of Beaulieu Road running north and south and Divden Bottom running in the east and west intersect, and similar traffic accidents have occurred many times over the years . The Ipley intersection is an intersection where the Beaulieu Rd running in the north-south is given priority, and the two roads intersect at 69 degrees. In addition, because it is on the flat ground and there are not buildings etc. in the surroundings, visibility is also good so it seems that traffic accidents are not likely to occur frequently.


However, in August 2011, a 15-year-old boy was riding a bicycle along the Beaulieu Road where the driver of the car coming from the left overlooked the bicycle, so he did not pause and went into the intersection Then they will hurt the boy and bear the injury of fracturing the clavicle. Also in May 2012 a similar traffic accident happens at the same intersection. The accident happened to Mr. Mark Brummell, who was cycling along the Beaulieu Road, the car driven by Stephen Chard overlooked the bicycle and invaded the intersection, hitting Brummell. Due to this accident Brummell died. In addition, similar traffic accidents occurred in the same intersection and the same situation in December 2016, Viral Parekh who was driving the car killed the victim Kieran Dix and Dix died doing. Although Mr. Chard admitted his own crime, although Parekh invaded the intersection at 37 mph (speed of approximately 60 km), no serious crimes were questioned.

The question to be asked here is "Why are similar car accidents occurring continuously at the same intersection continuously?" Make an actual Ipley intersectionGoogle Maps Street ViewCheck it out like this. Even if you check the intersection with the car's line of sight from the road, you still have a good view and you do not see many traffic accidents.


The most promising answer as to why accidents occur frequently at the Ipire intersection with good visibility is "Constant Traffic Angle Reduction RangeIt is the influence of the phenomenon called "It is a thing called. This phenomenon originates often in a ship or the like, and the two vessels move linearly at a stable speed toward a certain point, causing two ships to collide at the intersection. Generally it is the knowledge required at sea and aviation, it occurs in ships and aircraft traveling long distances at a constant speed in a certain direction, which is a phenomenon that rarely occurs in automobiles etc. where speed tends to change significantly.

In the case of ships and aircraft pilots, they are taught to change the direction of travel and take avoidance actions, but since the car runs on the road, it can not change the direction of travel. There are also problems peculiar to cars.

And there is a blind spot caused by "front pillar" as a problem peculiar to the car. The following figure shows the dead angle of the driver of the car, and it clearly shows that the scenery spreading beyond the front pillar becomes invisible to the driver.


If you show the picture of the Ipley intersection how this blind spot would hide the range, it is like this. If you are running Dibden / Bottom about 100 meters east of the Ipley intersection, the area painted purple will be the driver's blind spot and the Beaulieu Road will be invisible for about 12 meters. "There is a chance that you will miss six bikes with 12 meters," singletrackworld.com said.


When the car moves toward the Ipray intersection, the blind spot will move as follows. Considering that Parekh who caused the accident entered the intersection at the speed of 60 km / hour, we can move 100 meters in about 6 seconds, so the bicycle running the Beaulieu road suddenly appears at the intersection hidden behind the blind spot of the front pillar I think that enough.


The dead angle decreases as the car approaches the intersection, but the blind spot of the point one second before entering the intersection will be as follows, and as deadened by the light blue line on the Beaulieu Road, the blind spot remains I will. It seems that this is about the size of a bicycle.


Then, at what speed of the bicycle running the Beaulieu Road it will keep hiding in the blind spot of the car, saying that if the speed ratio is about 3 to 1 the bicycle will keep hiding at the blind spot . In order to keep entering the blind spot of a car running at about 60 km / h to the west from Dibden / Bottom, we need to run Beaulieu Lord south to about 13.5 mph (22 km / h), but this speed is for the bicycle Is enough running speed. The problem is not the point that "When a car runs at a speed of 60 km / h, a bicycle running at 22 km / h continues to hide in a blind spot", but if it is within the range of the speed of a car running Dibden / Bottom, whatever speed you are running It is the possibility that the bicycle keeps hiding in the blind spot.

In addition, singletrackworld.com points out that there is also a problem with the intersection angle of the Ipley intersection. At the Ipley intersection, it is said that three points "angle" should be considered, one of which is the "crossing angle at the intersection" and 69 degrees at the Ipley intersection. The second is the angle from the driver 's traveling line to the front pillar, which depends on the vehicle and the physique of the driver, but it seems to be about 17 degrees in angle. And the third is the angle to the automobile (possibly) which collides with the bicycle ride side traveling line, it will be 94 degrees at the Ipros crossing.

As you can see from this figure, the car that enters the intersection for cycling is just like the car coming from behind, which makes it hard to notice. Also, even though it is from the driver's side, there is a possibility that the bicycle can not be seen until 1 second before the collision, so although it is a coincidence product, the Ipley intersection creates a perfect angle where automobiles and bicycles tend to produce traffic accidents That is why.

byJake Blucker

Then it is not so at this intersection whether traffic accidents can not be avoided. First of all, if you decelerate the driving speed of the car greatly, the vehicle approaching at a constant speed from the right will move from the blind spot to the field of vision. You can also check the road at the blind spot if you move the head while the car is driving. It is possible that these simple methods could easily prevent traffic accidents at Ipley intersection.

However, there are also ways to reduce traffic accidents more easily. The solution was that the local residents submitted to the Democratic Representative, David Harrison, to change the Ipley intersection from a crossroad to two T-junctions. As a result, cars running in the east and west must decelerate whenever they reach the intersection, so there is a high possibility that the bicycle will pop out from the blind spot.


Although Representative Harrison has submitted this idea to the responsible agency, the layout of the Ipley intersection will not be changed, and Dix will die in the intersection two years after it was submitted.