When the road is constructed in patterns like rectangular, radial, hexagonal, etc for the proper management of traffic and also to interconnect the branch roads with main roads then it is called road pattern.
The main principle of road patterns is to reduce the time and distance that the vehicle takes to reach the destination place. It also focuses on the interconnection of branch roads.
It increases the response time of normal vehicles as well as emergency vehicles like ambulances, fire engines, etc. to reach the destination place.
Road Pattern also plays a vital role in the management of traffic but it is neglected by most countries. There are 6 types of road patterns that are mostly used.
2. Types of Road Pattern
1. Rectangular or Block Pattern
a. In this pattern; the whole area is divided into rectangular blocks.
b. Streets or branch roads intersect with each other at the right angle.
c. The main roads always pass through the centre and it should be wide enough.
d. Branch roads may be narrow as compared to main roads.
e. The main roads should be provided with a direct approach to outside the city.
~ The rectangular blocks can be further fractioned into small rectangles that may be used for the construction of buildings placed back to back, having roads on their front.
~ It is widely adopted on city roads.
~ Construction and Maintenance is quite easy.
~ It is not convenient because roads are perpendicular to each other. This increases the rate of accidents due to poor visibility at a perpendicular junction.
2. Radial or Star and Block Pattern
a. It is a combination of star and block patterns.
b. The entire area is divided into a radial network of roads radiating from the centre outwardly with a block pattern network of roads in between the radial main streets.
~ Less risky as compared to the rectangular pattern.
~ It reduces the level of congestion at the primary bottleneck location.
~ If one radial road is blocked then another can be used as an alternative.
~ Lack of safety appurtenances like rail transitions, crash attenuators and post support bases.
~ It is only effective when two-lane ramp traffic does not have to merge at the downstream end of the ramp.
3. Radial or Star and Circular Pattern
a. It is the pattern in which the main roads(radial roads) radiates from the central point and are connected with concentric roads(ring roads) that are also radiating outwardly.
~ It is safe as compared to the above patterns because vehicles travel in the same direction.
~ Roundabouts present in this pattern improves the efficiency of traffic flow. This also reduces fuel consumption and emissions of the vehicle.
~ Using a circular pattern in place of traffic signals reduces the possibility of rear-end crashes.
~ Providing a good curve during the implementation of this pattern is quite challenging.
~ It affects the driving ability. Mainly, old drivers face this problem due to declines(decrease) in vision, hearing, and cognitive functions.
~ There is necessary proper provision of the traffic signal, road markings and lighting to alert the drivers that they are approaching a roundabout.
~ Splitter Islands should be extended far enough to provide pedestrian refuge (crosswalk) and to delineate(describe ) the roundabout.
4. Radial or Star and Grid Pattern
a. This pattern is formed by the combination of Star and Grid Pattern.
b. As in other, a radial network of road radiates from the centre outwardly. Then, the main radial streets are interconnected by providing a grid pattern.
~ It increases the efficiency of land usage and unit density.
~ It improves the traffic flow in both directions utilizing Savannah’s cellular structure.
~ It provides high safety to vehicular traffic with a high proportion of 3-way intersections.
~ It reduces the cut-through traffic.
~ Splitter islands should be extended far enough.
~ High construction cost because of the need for extra traffic signals, road marking and lighting.
5. Hexagonal Pattern
a. In this, the entire area is divided into hexagonal patterns.
b. Three roads meet the built-up area boundary by the sides of the hexagons at every corner of the hexagon which can be further divided into suitable sizes.
6. Minimum Travel Pattern
In this, the city centre is connected with suburban centres and neighbour centres with the shortest roads. To make the road short; road alignment is made straight.
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