Showing posts with label intersection. Show all posts
Showing posts with label intersection. Show all posts
Type Of Intersection According to the structure
• intersections in the same plane (at-grade intersection)
This intersection is the intersection of the most common / prevalent, both in urban areas or in aerah out of town. This intersection is the meeting of two roads (or more) located in the same plane.
• intersections in the area that is not the same (Grade Separated Intersection)
This intersection is not a piece of a meeting between the road with high traffic road with high traffic / other low. Plot was made with a view to reducing / eliminating conflict points, thus the high road berlalulintas still have a high capacity.
A piece of the Cross Roads Roundabout (Roundabout) Part 3
In general, the roundabout has a radius of 60-100 meters, and the circular path 2 (two) lanes. When at one of the intensity beyond 2000 ktj. Traffic signal should be installed. Note however, that setting the ith traffic signals at the roundabout does not correspond to the real purpose of the roundabout, which creates a rotating flow that did not stop serving traffic. To the intensity of the 3000 ktj. Roundabout needs to be enlarged or increased to rotary interchange.
The limited ability of the system due to the limited length of the roundabout is weaving (the fabric) or "the maze", which is the area where the vehicle lane switching lanes or exchange.
A piece of the Cross Roads Roundabout (Roundabout) Part 2
Roundabout is also good enough to resolve the problem crossroads that have more than four arms.
Although this system can be applied to many circumstances, but very useful for highly branched junctions, only takes a broad area junctions, with the requirement that the volume being served is approximately equal to the volume intersections with lane dividers manage well.
A piece of the Cross Roads Roundabout (Roundabout) Part 1
Is the intersection form of the put / make a circle in it. The principle of the roundabout is to create a continuous flow of traffic to run without stopping. To achieve this goal, there are size requirements of the radius of the roundabout, which is adjusted to the volume of traffic served by the roundabout. This is due to the limited area of ??weaving (the area with the maze of traffic flow) or the fabric (MKJI) at a roundabout. The more traffic flow to deviate from each other, the larger the area weafing needed her, and led to the greater circle radius
Traffic flow conflict settings
Conflict setting traffic flow at a crossroads can be done by changing / separation time. Setting change / separation of traffic flow is known as phasing. The use and selection of the phases seen in the main conflict between the North-South traffic flow and the East-West. Because there are two major conflicts, then it can be solved with 2-phase. If at an intersection there are three major conflicts, then the 3-phase can be completed. These circumstances because of the two currents which veer to the right a little large on one approach, so that there are three major conflicts; as well if there are four major conflicts at intersections, can be overcome by using 4-phase system
A plot of the intersection of Crossroads with traffic signals
Intersection is a higher level of priority intersections. Volume of this intersection is served by more than 1200 ktj., So if it is not regulated by the signal, will cause a big delay.
Even in certain cases, vehicles that turn can lead to traffic congestion, because it can "lock" the flow of traffic. Intersections with traffic signals are also effective in reducing the number of traffic accidents, especially collisions face (rear accident). Although the signal is good enough to resolve the traffic problem, but the signal becomes less effective if the intersection has more than four arms. Signal is only fine if mounted on the intersection that has 3 or 4 arms only.
Basic guidelines for making canalization in Crossroads
Some principles of designing intersections canalization is:
a. Reducing the conflict area traffic flow. If the broad area of ??conflict, drivers and pedestrians alike will be confused, and it will be easy to crash.
b. Make the cut corners wherever possible flow angle approaching 90 °. It is intended to:
1) Reduce the area of ??potential conflict at the intersection
2) Provides a very pleasant conditions for drivers to consider the position and velocity relative safety
3) The flow of traffic to each other should be incorporated at a small angle. If the joint angles less than 15o, the merger will make a difference in the minimum speed, which will allow for the use of a small gap.
4) To reduce the speed of the vehicle that drove into the intersection, used several methods, such as the following:
a) funneling of approach (approach funnel-shaped)
b) Bending of approach (approach-shaped bend).
5) canalization that can separate the point of conflict between one another in an intersection.
6) canalization which makes it difficult, to prevent turning.
7) canalization which provide shelter area (refuge area) for turning vehicles and passing vehicles.
A plot of the intersection of Crossroads (Priority Intersections)
Intersection is the simplest form, the intersection of two roads that hierarchy (level) is different (eg, minor road and major road). This intersection serves a low volume, no more than 800 vehicles per hour (ktj), and to control use of traffic signs for STOP signs and / or YIELD signs, mounted on a lower level roads (minor road)
Some of the main things that need attention in the regulation of traffic flow at intersections Part 2
- Widening / adding lanes in the intersection. How this is done when the volume of turning traffic. The addition of lanes can be done in the next. adjacent to the outside or in the middle.
- Restrict vehicles turning at an intersection, when the vehicle is turning vehicles block basis, by placing the sign restrictions for certain vehicles.
- Install traffic signal when the total volume of all vehicles entering the intersection already exceeds the requirements of the feet, which is more than 800 vehicles per hour
A plot of the Crossroads (intersection)
In general the roads meet in one area; Junctions of this kind could serve the composition of the continuous flow of traffic and turned, only to a certain extent. According to its shape, can be distinguished as follows.
a. Three-pronged fork in the road (junction).
b. Four-pronged intersection (the intersection of four)
c. Branched junction (more than four)
d. Roundabout (rotary intersection)
Each of these intersections can be:
a. Common intersection (unchannelized)
b. Intersection with the addition of lanes (flared)
c. Crossroads with lane dividers (channelized)
Some of the main things that need attention in the regulation of traffic flow at intersections Part 1
General precautions with the canalization
1) Must be sure that the canalization is needed for traffic safety, increase capacity and smooth traffic flow, etc..
2) The width of the road should be feasible (possible)
3) Avoid the traffic island that many small pieces, and would be better off with some great size if possible.
4) avoid the movement many times - the merger of three movements into one movement offered a choice of three or more of the same.
5) Must be sure that the islands are easily visible on the approach.
6) It must be remembered that drivers and pedestrians do not always take the trouble
Intersection In Transportation Engineering Part 2
Crossing the road can be distinguished form the three Kinds:
a. Parcel road junction (intersection), ie two or more roads meet in the same plane.
b. Crosses, two or more roads INTERSECT, meaning That traffic flow from each of these roads can not get into another street.
c. Road intersection is not a plot (the intersection of compound), ie two or more roads meet That do not in the same field, but the traffic flow of each path can be Entered into the street.
Traffic Flow setting in Intersections
Philosophical basis of traffic flow at intersections settings is "to separate or regulate the movement of traffic into a conflict that must be part of the strip by using signs, traffic islands or to facilitate the safety and the two movements shared between vehicles and pedestrians."
Intersection In Transportation Engineering Part 1
Intersection is a form of building roads that lead to problems such as traffic delay (delay), congestion (congestions) and accidents (accidents). On a network of roads, the road junction can not be avoided or eliminated. Therefore, the above problems will inevitably occur, so that it becomes the task of traffic management experts to be able to cope.
Type Of Intersection According to the operation.
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• intersections without canalization (Unchannelized Intersection)
Intersection without canalization used on a minor road traffic of relatively low volume. However, in urban areas usually still be found even though the intersection without canalization lalulintasny have high volume. In general, to cope with the traffic signal is used masalan or STOP signs.
• intersections with canalization (Channelized Intersection)
The goal is to reduce points of conflict, by separating traffic movements, so as not to interfere with each other.
Separation can be done by creating a traffic island (traffic island), safety beam / column separator, and so on.
Type Intersection According to its shape
• 3-leg intersection
• 4-leg intersection
• Intersections with multi-arm
• Roundabout
Type Of Intersection
Crossing the road is a form of building roads that lead to problems such as traffic delay (delay), congestion (congestions) and accidents (accidents). On a road network, the intersection can not be avoided or eliminated. Therefore, the above problems will inevitably occur, so the task of traffic management experts to be able to overcome them.
Forms can be distinguished on the crossroads of three kinds:
a. Plot crossroads, ie two or more roads that meet in the same plane.
b. Crosses, two or more intersecting streets, meaning that traffic flow from each of these roads can not enter into another street.
c. No plot crossroads (intersection compound), ie two or more streets that do not meet in the same field, but the traffic flow from each of these roads can get into another street.
Advantages and Limitations of Traffic Rotary
Various advantages of rotary are follows:
- Crossing manoeuvre is converted into weaving or merging and diverging operations
- All traffic including those turning right or going straight across the rotary have equal opportunity as those turning left.
- The variable cost of operation of automobile is less in a traffic rotary than in a signalized intersection where the vehicles have to stop and proceed.
- There is no necessity of traffic police or signal to control the traffic as the traffic rotary could function by itself as a traffic controlled intersection and is the simplest of all controls.
- The possible number of accidents and the severity of accidents are quite low because of low relative speed.
- Rotaries can be constructed with advantage when the number of intersecting roads is between four and seven.
- The capacity of the rotary intersection is the highest of all other intersections at grade.
- Rotary requires comparatively a large area of land and so where space is limited and costly as in built up areas, the total cost may be very high.
- Where pedestrian traffic is large as in urban areas the rotary by itself cannot control the traffic and hence has to be supplemented by traffic police.
- In places where there is mixed traffic and large number of cylists and pedestrians, the design of rotary becomes too elaborate and operation and control of traffic also become complex.
- Where the angle of intersection of two roads is too acute or when there are more than seven intersecting roads, rotaries become trouble some.
- When the distance between intersections on an important highway is less, rotaries become trouble some.
Highway and Transport Engineering
and this section is about Advantages and Limitations of Traffic Rotary
(refference : Khanna, S.K., Justo, C.E.G., Highway Engineering, 3th edition, Nem Chand & Bros Roorkee (U.P.), 1976.))
Rotary Intersections
A rotary intersection or traffic rotary is an enlarged road intersection where all converging vehicles are forced to move round a large central island in one direction (clock wise direction) before they can weave out of traffic flow into their respective directions radiating from the central island. The main objects of providing a rotary are to eliminate the necessity of stopping even for crossing streams for vehicles and to reduce the area of conflict. The crossing of vehicles is avoided by allowing all vehicles to merge into the stream around the rotary and then to diverge out to the desired radiating road. Thus the crossing conflict is eliminated and converted into weaving manoeuvre or a merging operation from the right and a diverging operation to the left.
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Various design factors to be considered in a traffic rotary are:
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picture from : indianskyscraperblog.wordpress.com
Various design factors to be considered in a traffic rotary are:
- Speed
- Shape of central island
- Radius of rotary roadway
- Weaving angle
- Weaving distance
- Width of rotary roadway
- Radius of entrance and exit curves
- Channelizing islands
- Camber and superelevation
- Grade
- Lighting and signs
Highway and Transport Engineering
and this section is about Rotary Intersections
(refference : Khanna, S.K., Justo, C.E.G., Highway Engineering, 3th edition, Nem Chand & Bros Roorkee (U.P.), 1976.)
Channelized intersections (2)
The advantages of channelization may be summed up as follows:
1. By channelization vehicles can be confined to definite paths.
2. Angle of merging streams can be forced to be at flat angle so as to cause minimum disruption.
3. Angle between intersecting streams of traffic may be kept as desired in a favourable way..jpg)
picture from www.skyscrapercity.com
4. Speed control can be established over vehicles entering the intersection.
5. Refuge islands can be provided for pedestrians within the intersection area.
6. Points of conflicts can be separated.
7. The channelizing islands provide proper place for installation of sign and other traffic control devices
4. Speed control can be established over vehicles entering the intersection.
5. Refuge islands can be provided for pedestrians within the intersection area.
6. Points of conflicts can be separated.
7. The channelizing islands provide proper place for installation of sign and other traffic control devices
Highway and Transport Engineering
and this section is about Channelized intersections
(refference : Khanna, S.K., Justo, C.E.G., Highway Engineering, 3th edition, Nem Chand & Bros Roorkee (U.P.), 1976.)
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