Thursday, October 15, 2020

Sign regulations

SIGN REGULATIONS

  • Sign regulations in India are similar to those used in the UK
  • Urban roads and state highways have signs in the State language and English. National highways have signs in the State language, Hindi and English
  • The three main categories of road signs are:
    • Regulatory Signs- depicted in Circles and these sign shows Rules and regulations
    • Warnings-depicted in Triangle and 
    •  Information-depicted in Rectangle
  • Other sign boards which are Give Way(Shape is inverted triangle) and Stop (Shape is Octagon).
  • Circle with cross shows Prohibition and Circles without cross shows Rules. 
  • Triangles are pointy and considered as risk. 
  • Blue circles shows Positive Instructions and these signs are there for a particular class of vehicle. Otherwise, Regular color of sign board is Red and White.

Mandatory/Regulatory Signs

Cautionary/Warning Signs

Informatory Signs

Wednesday, October 14, 2020

Types of visual perception

TYPES OF VISUAL PERCEPTION

Visual perception is defined as the way one thinks about or understands something using ones senses. It refers to the ability to notice or understand something.

It is an active process of locating and extracting information from the environment aided by visible light. The physiological components involved in visual perception are called as the VISUAL SYSTEM consisting of knowledge from the fields of psychology, cognitive science, neuroscience and molecular biology.

Visual perceptual skills involve the ability to organize and interpret information that is seen and give it meaning

The goal behind designing road signs is to effectively warn road users. The signs should be designed to fulfill the requirements for safety in a given road environment and be visible from a long distance. This depends on:

  • Driving speed
  • Required viewing time
  • Point of disappearance (PoD)
  • Number of information elements
  • Driver's eyesight (Minute of Arc [MoA])

Minute of Arc is the minimum size of any detail of the provided road sign. It depends on the driver's eye sight. 

Other important issues involving visual perception are

  • Colour and contrast
  • Degree of comprehension of the meaning of designed information
  • Conspicuity of the design in the physical environment determined by (Conspicuity Index)

The various types of visual perception are
  • Peripheral visual field
  • Depth perception
  • Colour sensitivity
  • Static visual acuity
  • Dynamic visual acuity and
  • Figure ground discrimination
The above listed types of visual perception find applications in the below mentioned visual below mentioned visual perceptual skills. All of these skills essentially find application in the context of road safety.
Visual Memory allows a person to record, store and retrieve information. It allows learning and recalling later.
Visual Sequential Memory is similar to visual memory as it allows a person to store and retrieve information when necessary.
Visual Form Constancy is a visual skill that allows a person to distinguish one object from another similar object.For example, being able to tell the difference between the letter “b” and “d” or “3” and “8”. It is the ability to see and distinguish these differences is form constancy.
Visual Figure Ground is the visual skill that allows us to distinguish, segregate, isolate or find an object or stimuli in varying environments.
Visual Spatial Relations is the visual skill that allows people to process the visual environment around them and the location of objects in respect to each other.
Visual Closure is the visual skill that allows people to detect, differentiate, select, draw conclusions and understand information when they are only given certain pieces of information, rather than the entire account, story or explanation.
Visual Discrimination – The above six skills require some degree of visual discrimination. Visual Discrimination is the ability to identify detail, seeing similarities and differences items in shape, color, position and orientation.

Monday, October 12, 2020

Text versus Symbols

 Text versus Symbols

To evaluate the benefits of text and symbolic displays in highway signs relative to their familiarity on their comprehension speed and accuracy, drivers were presented with 30 traffic signs varying in their level of familiarity in three display conditions: 
  • standard symbol-only
  • text-only and 
  • symbol + text. 
Speed and accuracy of comprehension were recorded. Display condition and familiarity significantly affected both correctness of the answers and reaction time. Correctness improved when the symbol was shown with text, especially when the sign was less familiar.

This reinforces the belief that adding text improves the comprehension and reduces the time it takes to comprehend the sign, especially of unfamiliar signs.

Adding text could be a simple solution to making (unfamiliar) signs more understandable to a greater segment of the driving population without compromising comprehension time, thereby increasing traffic safety.

Symbolic images used for highway traffic signs are not always appropriate. 

Familiarity, standardization, and compatibility improve comprehension.

Violations of these ergonomic principles of design reduce comprehension. 

In such cases a text improves sign comprehension and reduces comprehension time.

Hence, it can be concluded that influence of ergonomic principles – 
  • familiarity
  • standardization and 
  • symbol-concept compatibility – on traffic sign comprehension showed that comprehension is highly correlated with the compliance with these ergonomic design principles

Location of Signs

 LOCATION OF SIGNS

Driving safely is affected by the locations where traffic signs are placed. The following points provide guidance on the sites where traffic signs should be placed.

  • Traffic signals are normally placed at intersections and crossings
  •  In some countries, these signals are placed ahead of the actual signal causing the traffic to stop well in advance of the intersection thereby enhancing the purpose of the signals (prevent accidents)
  • Traffic signs or road signs are signs erected at the side of or above roads to give instructions or provide information to road users

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