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Explore CE 552 objectives related to Positive Guidance, analyze driver tasks and performance, assess information systems, develop improvements, and learn driving task components like Navigation, Guidance, and Control. Study Traffic controls, human factors, and principles of Primacy, Expectancy, and Redundancy for effective roadway design and safety.
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Positive guidance concept • Provide drivers sufficient information about roadway design, operations, and potential hazards so they respond correctly and avoid crashes
CE 552 objectives related to PG • Identify problems Crash data, complaint files, site diagrams • Analyze driver tasks / performance On-site speed and driver studies • Assess the current information system Road safety audits a portion of this • Develop and evaluate improvements or modifications to the information system
Driving Task Components • Navigation • Guidance • Control • Class - what are the elements of each?
Driving Task: Navigation • Route selection • Distance to destination • Interchange / route change locations • Directions of roadways - i.e. general elements associated with trip planning
Driving task: Guidance Vehicle operator is in decision mode regarding lane placement, speed and more while considering existing: • Horizontal and vertical alignment • Roadway cross sections • Roadside obstacles • Traffic signage / controls • Traffic features - volume _ speeds
Driving Task : Control • Driver in reactionary mode • receives input from senses relating to vehicle handling. Examples: superelevation pavement texture speed / acceleration
Examine Guidance section:Traffic controls and human factors • D_R_D_R related to information or control signs (Detect, Recognize, Decide, React) • 1) D R D R distances • 2) Ability to read and recall information / driver visual acuity • 3) Primacy • 4) Expectancy • 5) Redundancy
Principle of Primacy Concept of primacy asserts that at any given moment, some information is more important than other information. • Control information is more important than guidance information • Guidance information is more important than navigation information. • Information about some hazards is more important than information about other hazards.
Principle of Primacy - Spreading Distribute information to driver to avoid peaks and valleys. peaks of information cause visual and memory overload. Distribute less important information to secondary position or valleys
Principle of Expectancy • Expectancy affects the perception and use of information. People expect certain things to appear and operate in certain ways. • Where do expect to find the light switch? Move switch up or down to turn light on? • Hot water on left or right? Turn clockwise or counter-clockwise to shut water off? (Tougher question )
Principle of Expectancy • Hot water on left or right? • Turn clockwise or counter-clockwise to shut water off? (Tougher question )
Principle of Expectancy How does this relate to highway safety design and controls? Exit ramps - _______ Color red - ________ Curve sign or turn sign - _______________ Chevron to indicate lane shift - ___________
Principle of Redundancy Recognize that different driver’s pick up cues in different ways AND short term memory is short, additional input is needed Example: Redundancy by _________________
Redundancy – earlier example But other issues may “trump” the redundancy card
Analysis zones in Positive Guidance Basic analysis zones: Advance zone - distance before driver needs to be aware of hazard zone Approach zone - decision sight distance minus stopping sight distance Non-recovery zone - stopping sight distance Hazard zone - distance of hazard
Non – recovery zone Non – recovery zone is based on stopping sight distance (SSD). SSD = 1.47 V * t + V2 / (30( f +/- g)) What are the units for the above expression? What are appropriate values for t and f? [ g = grade in ft per ft ]
