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CVEN 4405 Human Factors in Civil and Transport Engineering

Term 3 2020 Week 4 - Lectures 1a and 1b

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CVEN4405: Human Factors in Civil and Transport Engineering

Human Factors in Traffic Engineering 1

Introduction and the Driving Task Term 3, 2020

Week 4, Lecture 1a

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Welcome Back!

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Course Coordinator and Lecturer

Prof. Michael Regan, PhD Professor of Human Factors

Research Centre for Integrated Transport Innovation (rCITI) School of Civil and Environmental Engineering

University of NSW Sydney

T: +61 (0)2 9385 9504 E: [email protected]

Staff Webpage

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The CVEN 4405 Teaching Team

Coordinator and Lecturer Prof. Michael Regan Professor of Human Factors Research Centre for Integrated Transport, UNSW Sydney E: [email protected]

Teaching Fellow Dr Prasannah Prabhakharan Research Fellow Research Centre for Integrated Transport, UNSW Sydney E: [email protected]

Demonstrator Mitch Cunningham E: [email protected]

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Review of Last Lecture

• Individual differences • Alcohol • Other drugs • Inattention and distraction

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This lecture - Overview

• Introduction to Human Factors in Traffic Engineering • The “Safe System” approach to road safety • The Driving Task

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Learning Outcome for this Lecture

Up until now, the lectures have been designed around the first Learning Outcome:

• CLO1: Explain the fundamental principles of HF that can be used by civil and transport engineers to facilitate user-centred design

For the next 4 weeks, the lectures will be designed around the second Learning Outcome:

• CLO2: Apply HF principles, methods and data to the design of road and traffic management systems

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Learning Outcomes

CLO1: Explain the fundamental principles of HF that can be used by civil and transport engineers to facilitate user- centred design

CLO2: Apply HF principles, methods and data to the design of road and traffic management systems

CLO3: Plan for the integration of HF into the design lifecycle of the road and traffic management system

Introduction to Human Factors in Traffic Engineering

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Imagine This ….

• “Imagine someone enthusiastically bursting into your office with the news that they had invented a new system that was cheap for users but which also offered a range of extra benefits depending on how much you were prepared to pay, a system that could be used by young and old alike to enhance their mobility and enable them to cover large distances in a reasonable time, a system that was usable at all times and in all but the most severe weather conditions. And it would be so popular that the average person in the developed world would use the system to cover thousands of kilometres annually.”

• Sound familiar?

Source: Fuller and Santos, 2002, p. 1

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However….

• “Then they told you the down side. The system, if applied worldwide, would consistently kill about half a million people a year, around 100 thousand in the US and the EU, and that in addition up to seventy times as many people as this would be injured, with perhaps one in ten maimed for life. And oh yes, there would be untold material damage as well. You might be inclined to send them back to the drawing board.”

Source: Fuller and Santos, 2002, p. 1

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Human Factors and the Traffic Engineer (1)

• In order to design the transport system from a user-centred perspective, traffic engineers need to know the characteristics of the people for whom they are designing and managing the road transport system – i.e. road users

Source: Fuller and Santos, 2002, p. 2

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Human Factors and the Traffic Engineer (2)

From a Human Factors perspective, they need to understand: – road user needs, motives and goals – what limitations they have in vision, human information processing

and in speed of responding – how they perceive the road and traffic environment – how their perceptions of the road and traffic environment vary with

age and experience, fatigue, stress and emotion – why collisions happen and how they can control behaviour to

prevent them from happening

Source: Fuller and Santos, 2002, p. 2

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Human Factors and the Traffic Engineer (3)

• “For so long, engineers have had to act as protopsychologists, making sometimes intuitive guesses about about how road users might respond to various proposed design features, often using themselves as reference road users and iteratively carving out modified design solutions in the light of experience. In the process they have rediscovered a range of basic psychological facts and principles. But the science of [Human Factors] has more to offer.”

Source: Fuller, 2002, p.2

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Introduction to Human Factors in Traffic Engineering (1)

The road traffic system essentially comprises three main elements:

• the human (i.e. road users) • the vehicle • the road.

Source: Ogden, 1992, p. 2.1.2; Fuller & Santos, 2002, p. 2

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Introduction to Human Factors in Traffic Engineering (2)

The system is fundamentally unstable:

• Infrastructure is mixed (narrow back roads through to highways)

• Road users are generally independent elements, with different properties, doing different things (walking, driving etc)

• The system communicates with road users via many different modes (e.g. signs and signals, in-vehicle displays)

Source: Ogden, 1992, p. 2.1.2; Fuller & Santos, 2002, p. 2

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Introduction to Human Factors in Traffic Engineering (3)

The inherently unstable transport system is maintained in equilibrium by the frequent intervention of the human (i.e. road users).

Road users regularly make adjustments to avoid collisions and to compensate for the errors of other road users.

Something goes wrong with this process once every 80,000km or so for the average driver in a developed country

Source: Ogden, 1992, p. 2.1.2; Fuller, 2002, p. 10

The Safe System Approach to Road Safety

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The “Safe System” Approach to Road Safety Management

https://www.roadsafety.gov.au/nrss/safe-system.aspx

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Introduction to Human Factors in Traffic Engineering (4)

• The Safe System approach to road safety management reveals that road and traffic engineers have a range of roles to play in enhancing safety.

• Ultimately, the function of much of traffic engineering is to help road users travel safely from one location to another.

• “Knowledge of human performance, capabilities and behavioural characteristics is thus a vital input to much of the road and traffic engineer’s task and a prerequisite to understanding how human behaviour may be influenced.”

Source: Ogden, 1992., p. 2.1.2

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Introduction to Human Factors in Traffic Engineering (5)

• Traffic engineering is concerned with various aspects of traffic control

• Such control is usually introduced through, or relies on, influencing road user behaviour.

• e.g. traffic signs and signals are ineffective if drivers don’t see, interpret, respond to, and obey them.

Source: Ogden, 1992., p. 2.1.2

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Introduction to Human Factors in Traffic Engineering (6)

• “The safe operation of the road system depends fundamentally upon the road user - driver, rider and pedestrian - making a series of sequential decisions, which need to be correct, or if incorrect, implemented in a forgiving environment.”

Source: Ogden, 1992., p. 2.1.2

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Introduction to Human Factors in Traffic Engineering (7)

The road and traffic engineer has a vitally important role to play in assisting road users to make correct decisions:

• by helping to control the rate of decision- making to that which road users are capable of accommodating

• by presenting traffic information in a way that facilitates rapid and correct decisions.

Source: Ogden, 1992., p. 2.1.2

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Introduction to Human Factors in Traffic Engineering (8)

• To do that, the traffic engineer needs to understand:

• what tasks drivers (and other road users) perform when using the road and traffic system, and

• their information processing capabilities and limitations and vulnerabilities when they perform these tasks.

Given the critical role of motor vehicle drivers in nearly all road crashes, the primary focus of this course will be on vehicle drivers, although we will also consider other road users.

Source: Ogden, 1992; Fuller & Santos, 2002

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Introduction to Human Factors in Traffic Engineering (9)

• Human Factors is now a well-established science and profession.

• Many of its findings are incorporated into road design standards in various countries – as early as the 1930s

• Roads should be designed and managed to take account of human factors – otherwise it is unlikely that a Safe System can be achieved

Source: PIARC (2015)

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Introduction to Human Factors in Traffic Engineering (10)

• Since knowledge in Human Factors continues to evolve, many of its findings remain to be absorbed into guidelines and technical standards

• The tutorial this week, along with one of the required readings (Austroads Guide to Traffic Management Part 13: Road Environment Safety) will help to:

• put into context the lectures so far, and • expose you to some of the key Human Factors-related

standards and guidelines you will need to become familiar with as Traffic Engineers.

The Driving Task

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The Driving Task

• There are some occasions when drivers have to respond to an unexpected event (e.g. a child running unexpectedly across the road to its parent).

• However, for most of the time drivers “execute planned actions which are shaped by their expectations of the unfolding road, pedestrian and traffic scenario in front of them and the reality that they actually observe.”

Source: Fuller, 2002, p. 4

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The Driving Task – Brown’s Model (1)

• Driving a car is a complex, multi-task, activity requiring the performance of around 1500 sub-tasks

• So it’s not surprising that people find it so difficult to learn how to drive.

• Many models of the driving task have been proposed. • During this lecture we will discuss two models:

• Brown’s (1986) model • Theeuwes’ (2002) model

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The Driving Task - Brown’s Model (2)

Brown (1986) characterises driving as involving six functions:

• Route finding • Route following • Lateral control • Collision avoidance • Rule Compliance • Vehicle monitoring

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The Driving Task - Route finding (1) • Route finding is performed mainly by drivers who are

unfamiliar with the area in which they are travelling.

• It involves visual search for symbolic and text-based road signs, or for landmarks memorised from a prior study of maps, etc

• At the sensory level, searching for route information usually requires visual scanning away from the direction in which the vehicle is travelling. Is that a problem? Why?

Source: Brown (1986), p. 3

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The Driving Task - Route finding (2) • Route finding cannot be performed simultaneously with

the monitoring components of vehicle steering and collision avoidance.

• It must be “interleaved” with these control functions in a way which minimises risk, at a moment when traffic ahead may well be reducing speed prior to making route changes.

• Perceptual, attentional and decision making, which we talked about earlier in the course, are important requirements for route finding.

Source: Brown, 1986 (p. 4)

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The Driving Task - Route finding (3) • Drivers in unfamiliar areas often have a mental

representation of their route in long-term memory.

• Hence, long-term memory is important for route finding. Errors can occur as a result of incorrect recall, omission or transposition of items that have been memorised in sequence.

• Working memory is also important. Information from destination signs, for example, has to be stored in working memory until the driver implements it as route following behaviour .

Source: Brown, 1986 (p. 4)

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The Driving Task - Route Following (1)

• Route Following is a function performed - mainly by drivers - in a familiar traffic environment as they follow a path (the road) from one well-known landmark to another.

• The human information processing load on the driver in this case is minimal, leaving spare capacity for the performance of other functions, such as collision avoidance.

Source: Brown, 1986 (p. 4)

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The Driving Task - Route Following (2)

• When following a familiar route, the behaviour of the driver will be determined more by expectancy and prior experience of the route, rather than by responding to the immediate demands of the environment.

• As we will discuss, accidents often occur when drivers’ expectancies are not met/are violated – e.g. at newly implemented roadworks.

Source: Brown, 1986 (p. 4)

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The Driving Task – Lateral Control • Lateral Control is the function performed by drivers as

they steer along their chosen route at the appropriate speed.

• Drivers use central directional information and peripheral ‘streaming’ cues to control steering and remain on course.

• For experienced drivers, under normal conditions, this function is usually undemanding and is largely performed without any conscious awareness.

Source: Brown, 1986 (p. 6)

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The Driving Task - Collision avoidance (1) • Collision avoidance is a major functional requirement

of driving

• Involves a wide range of human information processing skills.

• A major requirement of this function is hazard perception, which may involve:

• a directed visual search for predictable hazards • the detection and identification of unpredicted

hazards.

Source: Brown, 1986 (p. 9)

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The Driving Task - Collision avoidance (2)

• Directed visual search for predictable hazards requires forward planning.

• Experienced drivers and those travelling on familiar roads are better at forward planning than young novice drivers or strangers driving through an area.

• Detecting unpredicted hazards is more a function of alertness, although it is not completely independent of driving experience.

Source: Brown, 1986 (p. 9)

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The Driving Task – Rule Compliance (1) Rule compliance is a necessary functional requirement because drivers and other road users share use of the traffic system.

This function requires memorisation of road rules in long- term memory and also compliance with information displayed visually to the driver.

Therefore, accidents can result from: • ignorance or disregard of rules • failure to implement memorised rules or displayed

instructions appropriately.

Source: Brown, 1986 (p. 11)

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The Driving Task – Rule Compliance (2)

Certain road rules, such as maximum speed limits, apply across a wide range of traffic conditions

This tends to make people violate laws when they think it is safe to do so.

Source: Brown, 1986 (p. 11)

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The Driving Task - Vehicle Monitoring (1)

• Vehicle Monitoring involves monitoring the status of the vehicle eg speedometer, warnings, fuel guage.

• In modern vehicles, this function places few demands on the driver.

• The shift in vehicle cockpits from analogue displays of vehicle state (e.g. engine temperature) to normally blank warning signals (which light up and make noise only if engine temperature is too high) leaves the modern driver very little to actively monitor.

Source: Brown, 1986 (p. 12)

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The Driving Task - Vehicle Monitoring (2)

• Vehicle monitoring in modern vehicles, therefore, is for most of the time unlikely to distract the driver from the performance of the other driving functions that they have to perform

• Except, for example, if they are almost out of petrol and monitor the low fuel light to the point where it distracts them from other more safety-critical functions (e.g. accident avoidance).

Source: Brown, 1986 (p. 12)

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The Driving Task - Vehicle Monitoring (3)

A WISE PREDICTION:

“... Nevertheless, we should perhaps keep a wary eye on the use of new technology for in-vehicle instrumentation. There is a tendency for this field to be hardware-driven and we should ensure that dashboard gimmicks do not distract drivers from their other more important functions of interfacing with the traffic environment.” (p. 12)

Source: Brown, 1986 (p. 12)

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Driving Task Demands

• There are a number of factors that contribute to the overall demand placed on the driver at any moment in time:

• The environment - roadway, physical conditions, visibility • Other road users - with whom driver interacts • The vehicle - displays, controls and operating requirements • Speed – the demands on information processing increase with

increased speed • Road position and trajectory – i.e. geometry

Source: Fuller, 2002, p. 4 (see model next slide)

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The Driving Task – Demand Model

• INSERT FULLER’S DIAGRAM HERE

Source: Fuller, 2002, p. 5

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Driver Capability (1)

• Drivers brings to the driving task a number of characteristics that enable them to attempt to perform the driving task effectively and safely:

– Constitutional characteristics – i.e. human information processing abilities

– Knowledge and skills – from education, training and driving experience – that define their upper limit of their driving competence

Source: Fuller, 2002, p. 5

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Driver Capability (2)

• As discussed earlier in this course, humans have certain human information processing limitations and vulnerabilities – human factors

• As a result, drivers are not always able to perform at their upper limit of competence

• Human factors interact with drivers’ competence to produce their momentary capability (this is shown in the model on next slide)

Fuller, 2002, p. 5

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Driver Capability Model

Source: Fuller, 2002, p. 5

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The Demand – Capability Interface

Fuller (2002) has proposed a simple model of the interface between driving task demand and driver capability (on next slide). Basically:

• If capability exceeds task demand, the driver is able to progress safely

• If task demand exceeds capability, then a collision or loss of control will occur – unless another road user makes some sort of compensatory manoeuvre to help them avoid the collision

Fuller, 2002, p. 6

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The Demand – Capability Interface Model

Source: Fuller, 2002, p. 6

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The Driving Task – Information processing requirements (1) Brown’s six driving functions require the driver to perform several information processing tasks:

• receive inputs (most of which are visual) • eg amber traffic signal

• process them • eg that means “caution”

• make predictions about alternative responses • eg “should I go through lights or slow down”

• decide which response is the most appropriate • eg “I’d better slow down, as light is about to change to red”

Source: Lay, 1986, p317; in Ogden, 1992 (p. 2.1.2)

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The Driving Task – Information processing requirements (1) Brown’s six driving functions require the driver to perform several information processing tasks (cont…):

• execute the response(s) • eg “apply the brakes”

• observe their effects through the reception and processing of new information (i.e. through feedback) • eg “just as well I decided not to go through the amber light, or it

would have been red”

Source: Lay, 1986, p317; in Ogden, 1992 (p. 2.1.2)

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The Driving Task – Problems (1) • There are some problems in this sequence of

information processing tasks. These arise from:

• the capabilities and limitations of the human driver

• the interfaces between the human the other elements of the road traffic system (the road and the vehicle).

Source: Ogden, 1992 (p. 2.1.2)

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The Driving Task - Problems (2)

These problems include:

• inadequate or insufficient input available to the driver for the task at hand (e.g. during night time driving)

• drivers have difficulty in handling extreme inputs or uncommon events

• drivers may sometimes sample inappropriate inputs or process them too slowly

Source: Lay, 1986; in Ogden, 1992

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The Driving Task – Problems (3)

• when they become overloaded, drivers tend to shed part of the input demand to deal with what they judge to be more important; but it may not be…

• driver stress, arousal, conditioning, inexperience, and other factors may all lead to errors and misjudgments

• drivers, as humans, are imperfect decision-makers

• drivers are prone to errors

Source: Ogden (1999, p 2.1.3)

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The Driving Task - Problems (4)

• the traffic system, itself, is inherently unsafe:

• “the designers and operators of the system have created a situation in which human fallibility inevitably leads to injury and death” (Carsten, 2002, p. 14)

Source: Ogden (1999, p 2.1.3); Carsten, 2002, in Fuller and Santos, 2002, p. 14

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Questions ?

Over to ….

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Required Reading

Austroads (2017). Austroads Guide to Traffic Management Part 13: Road Environment Safety (3rd Edition). Sydney, Australia: Austroads.

• Chapter 1 – Introduction • Chapter 2 – Safe Road Environment • Chapter 3 – Human Factors and the Need to Design and Manage Roads to

Achieve a Safe System • Chapter 4 – only section 4.5.4 Managing Driver Workload

E- copies available via UNSW Library

Prof. Michael Regan, PhD Research Centre for Integrated Transport Innovation

(rCITI) Room 112, Civil Engineering Building (H20)

E: [email protected]

CVEN4405: Human Factors in Civil and Transport Engineering

Human Factors in Traffic Engineering 2:

Road Trauma, Crash Types, Road Users and Contributing Factors

Term 3, 2020

Week 4, Lecture 1b

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Guest Lecturer

Dr. Prasannah Prabhakharan Research Fellow

Research Centre for Integrated Transport Innovation (rCITI)

School of Civil and Environmental Engineering, UNSW SYDNEY

E: [email protected]

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Learning Outcomes

CLO1: Explain the fundamental principles of HF that can be used by civil and transport engineers to facilitate user-centred design

CLO2: Apply HF principles, methods and data to the design of road and traffic management systems

CLO3: Plan for the integration of HF into the design lifecycle of the road and traffic management system

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Course Learning Outcome 2

• What does the data say about how and why crashes are occurring?

• What human factors principles need to be applied to reduce road trauma?

• How can the safe system be utilised to think about all elements for the road network?

CLO2: Apply HF principles, methods and data to the design of road and traffic management systems

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A Bit About Me - Education

BSc (Hons) – School of Psychology, UNSW • Visual Perception

PhD – School of Aviation, UNSW • Traffic Psychology/Human Factors • Young Novice Driver Behaviour

Graduate Certificate in University Learning and Teaching – School of Education, UNSW

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A Bit About Me - Research Interests

Future Vehicles and Transport • Human Factors issues in a Connected and Automated vehicle network • Diffusion of Innovation and Adoption of Technology

Vulnerable Road User Safety • Motorcyclist, Pedestrians and Cyclists • Cognition over the lifespan

Attention and Perception of Road Users • Hazard Perception • LBFTS crashes

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A Bit About Me - Experience

• Worked for TfNSW – RMS (Hunter Region) and NSW Centre for Road Safety

• Understanding how crashes are understood and what interventions are put in place to mitigate crashes.  Major Regional Highway Operations

 Hunter Region blackspot nominations

(State and Local)

 NSW Behavioural Campaign

(Look Out Before You Step Out)

Definitions

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Definitions: Road Crashes vs Road Accidents

In modern convention, we shouldn’t use the term “accident”. • An "accident" are typically:

» Unintentional » Unforeseen » Not be preventable

• E.g. “Freak accident”

• Planes and trains do not have 'accidents' - they crash.

• There is an inherent complacency when we use the term “accident”.

• Changing language is vital to change attitudes towards road trauma.

Source: http://www.roadpeace.org/take-action/crash-not-accident/

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Definitions: Injury Severity in Road Crashes

If the police don’t attend the crash, or there is no injury that requires a hospital, we largely don’t see these crashes..

Casualty Description

Fatality A person who dies within 30 days from injuries received in a road traffic crash

Serious Injury (SI) A person linked to a hospital stay containing an injury diagnosis on the same day or the day after a crash and did not die within 30 days of the crash; or linked to a Lifetime Care participant record. (matched if with police record, unmatched if not)

Moderate Injury A person matched to an emergency department attendance record on the same day or on the day after a crash but was not killed or not subsequently admitted to hospital

Minor Injury Person identified as a casualty in the Police crash report data who is not matched to a hospital stay or an emergency department attendance record

The Crash Problem

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The Problem: Road Trauma Internationally

• According to WHO Global Status Report On Road Safety 2018: • The number of deaths on the world’s roads is an estimate:

• 1.35 million people dying each year.

• Road traffic injuries are now the leading cause of death for children and young adults aged 5–29 years.

• More people now die as a result of road traffic injuries than from HIV/AIDS & tuberculosis.

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The Problem: Road Trauma in Australia

The National Road Safety Strategy (NRSS) reports:

• FATALITIES - Each year, ~1,200 people die on Australian roads.

• SERIOUS INJURY - At least another ~40,000 people are admitted to hospital.

• These can be lifechanging injuries, such as paralysis, brain injuries, amputations or loss of sight.

• The economic cost of road crashes in Australia is estimated between $27-30 billion per annum

• Set an ambitious target to reduce fatalities and serious injuries by 30% by 2021 (from 2008-2010 baseline).

• We are not on track to achieving this goal.

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Trends in Fatalities in Australia

Overall downward trend in fatal crashes..

Source: BITRE (2019) Road trauma Australia 2019 statistical summary

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Trends in Serious Injuries in Australia

SI injuries are on the rise…

Source: BITRE (2019) Road trauma Australia 2019 statistical summary

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How does NSW/Australia compare to the rest of the world, in terms of fatalities?

Source: BITRE (2019) Road trauma Australia 2019 statistical summary

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In NSW…

Source: NSW Road Safety Plan 2021

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WHY: Contributing Factors to Fatal Crashes (NSW)

Distraction/Inattention ~10%? (under reported)

Source: NSW Road Safety Plan 2021

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WHY: Contributing Factors to Fatal Crashes (NSW)

• Some of these problems have been long persistent and difficult to change (e.g. Speeding)

• Others we’ve seen huge improvements due to the interventions we’ve put in place (e.g. Drink Driving).

• Others are new and emerging (e.g. impairment due to drug use, technology and distraction)

Source: NSW Road Safety Plan 2021

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WHERE: Contributing Factors by Urbanisation (NSW)

• Whilst most Serious Injury crashes occur in Metropolitan areas, most Fatal crashes occur in rural area.

Source: NSW Road Safety Plan 2021

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WHO: Road User Class

5 broad categories: • Drivers (light and heavy vehicles) • Passengers (light and heavy vehicles) • Motorcyclists • Bicycle riders • Pedestrians

Source: NSW Road Safety Plan 2021

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WHO: Crashes by Road User Group in NSW

• Distribution of fatalities and serious injury crashes by road user class is different.

• “People who walk or ride a bicycle or motorcycle are vulnerable in a crash as the unprotected body can only tolerate so much force”

Source: NSW Road Safety Plan 2021

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% of Road User Fatalities in Regions

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HOW: Road User Movements Codes

Source: NSW CRS (2019) - Definitions and notes to support road crash data

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HOW: RUM code categories

00s Pedestrians

10s Vehicles from Adjacent Direction (Intersection)

20s Vehicle from Opposing Direction

30s Vehicle from Same Direction

40s Manoeuvring (e.g. U-turn)

50s Overtaking ( e.g. cutting in)

60s On path (i.e. hit an object on the roadway)

70s Off path on a straight

80s Off path on a curve or turning

90s Misc (e.g. falling from a vehicle, ‘run away’ vehicle)

Source: NSW CRS (2019) - Definitions and notes to support road crash data

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HOW: Most common fatal crash type by RUM

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So how does we mitigate these crashes?

We know the (for the most part): • WHY = Contributing Factors • WHERE = Urbanisation • WHO = Road User Class • HOW = RUM codes from crash data

What levers can you use to change road crash problems?

The Safe System

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The ‘Safe System’ Approach to Road Safety Management

1. People make mistakes. Humans will continue to make mistakes, and the transport system must accommodate these. • a simple mistake shouldn’t cost anyone their

life.

2. Human physical frailty. There are known physical limits to the amount of force our bodies can take before we are injured.

3. A ‘forgiving’ road transport system. a Safe System ensures that roads, roadsides, vehicles and speeds need to be designed to minimise crashes or reduce forces if a crash happens.

4. Road safety is a shared responsibility. Everyone needs to make safe decisions on and around the road to prioritise safety.

Source: NRSS: Safe System principles - https://www.roadsafety.gov.au/nrss/safe- system.aspx; https://towardszero.nsw.gov.au/safesystem

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The ‘Safe System’ Approach to Road Safety Management

As future Traffic Engineers, we know you can utilise at least three of the four Safe System Pillars:

• Safe Roads and Roadsides

• Safe Speeds

• Safe People

As future policy makers, you have an ability to influence other parts of the safe system (including the outer layers)

Source: NRSS: Safe System principles - https://www.roadsafety.gov.au/nrss/safe- system.aspx

Safe Road and Roadsides

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SAFE ROADS: Treatments for RUM 70s + 80s

Two major treatment options are typically utilised: 1. Barrier treatment

– W-beam

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SAFE ROADS: Treatments for RUM 70s + 80s

Two major treatment options are typically utilised: 1. Barrier treatment

– Tri-beam (for truck crashes, or sharp curves)

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SAFE ROADS: Treatments for RUM 70s + 80s

Two major treatment options are typically utilised: 1. Barrier treatment

– Wire-rope

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SAFE ROADS: Treatments for RUM 70s + 80s

Source: https://youtu.be/0iGcwATYH4I

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SAFE ROADS: Which barrier to use?

You need to consider the types of crashes that are occurring to identify the right barrier.

• e.g. if you have motorcycle crashes, regular w-beam (or wire rope) would not be ideal…

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SAFE ROADS: Which barrier to use?

Source: https://youtu.be/GUBYd3bJUHE

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SAFE ROADS: Which barrier to use?

Solution: w-beam with rub rail

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SAFE ROADS: Treatments for RUM 70s + 80s

Two major treatment options are typically utilised for : 2. Widening the shoulder

– Allows for more room for error correction

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SAFE ROADS: Treatments for RUM 20s

Separation is the preferred method. • Wide centreline treatment • Cost effective solution

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SAFE ROADS: Treatments for RUM 20s Separation is the preferred method.

• Median separation

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SAFE ROADS: Treatments for RUM 20s

Separation is the preferred method. • Barrier separation

• Concrete (‘Jersey Barrier’ or precast concrete)

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SAFE ROADS: Treatments for RUM 20s

Separation is the preferred method. • Redirective barrier treatments

• Elsholz barrier • Redirect vehicles back to road way – instead of mounting

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SAFE ROADS: Treatments for RUM 20s

Separation is the preferred method. • Redirective barrier treatments

• Wire rope (flexible) treatment

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SAFE ROADS: Treatments for RUM 20s

Source: https://youtu.be/91j_Mhv1j30

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SAFE ROADS: Treatments for RUM 00s

Directing pedestrians towards established road infrastructure: 1. Pedestrian fence is typically used to ensure they are not

crossing at the wrong spots • Can be used as a barrier treatment (but not ideal) • Suitable for high pedestrian areas

Source: https://www.rms.nsw.gov.au/business-industry/partners- suppliers/documents/standard-drawings/r0800-23.pdf

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SAFE ROADS: Treatments for RUM 00s

Directing pedestrians towards established road infrastructure: 2. Pedestrian refuges

• Provide ped protection from vehicles • Accommodates ped movements into smaller gaps

Case Study: Site Investigation Process (SIP)

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Case Study: Site Investigation Process (SIP) Allandale Road/ Wollombi Rd, Cessnock

• A location was identified where a significant number of crashes had occurred

• Network & Safety Management teams’ (RMS) role was to identify why theses crashes were occurring and propose potential countermeasures

• A Site Investigation Process (SIP) was conducted

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Case Study: Overview of the Crash Data

23 crashes (20 Casualties) – 3 serious injury – 5 Moderate injury – 5 uncategorised injury – 10 non-casualty crashes

RUM Codes • 11 opposing vehicles turning (5 injury, 7 in darkness & 6 non injury crashes) • 4 hit pedestrian • 2 off road on straight, hit object • 2 rear end • 1 leaving driveway • 3 other crash type

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Case Study: Summary Crash Report

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Case Study: Crash Diagram (Peds only)

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Case Study: Crash Diagram (all)

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Case Study: Aerial View

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Case Study: Site Investigation

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Case Study: Field Observation

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Case Study: Field Observation

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Case Study: Field Observation

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Case Study: Field Observation

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Interventions Proposed

Wollombi Rd - Right turn movement (consists of 11 crashes, WB vehicles turning right colliding into EB vehicles)

1. Change filter phase timing • Prior to SIP

– Red arrow before was between 8am – 9pm » Had 9 right through crashes occurring.

• After SIP – Red arrow was extended to times between 5:30am – 10pm

» New time slot only 2 crashes

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Interventions Proposed

2. Install Ped fence with Elsholz along Allandale Rd

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Interventions Proposed 3. Request council to remove or relocate Advertisement

sign on Allandale Rd SB approach.

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Key Take Home Messages

• Road trauma is a continuing issue in most countries. • The entire ‘Safe system’ needs to be considered

• People make mistakes. • Human can only withstand so much force before

they are injured. • Our job is to reduce trauma when a mistake occurs

• The crash problem is forever changing and evolving • Understanding the unique problem allows for

targeted solutions.

Dr Prasannah Prabhakharan Research Centre for Integrated Transport Innovation

(rCITI) Room 111B, Civil Engineering Building (H20)

E: [email protected]

CVEN4405: Human Factors in Civil and Transport Engineering

Human Performance Limitations and Traffic Engineering 1:

Vision and Driving Term 3, 2020

Week 4, Lecture 2

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CVEN 4405 Human Factors in Civil and Transport Engineering

Term 3 2020 Week 2 - Lectures 1a and 1b

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Lecture Recordings

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Course Coordinator and Lecturer

Prof. Michael Regan, PhD Professor of Human Factors

Research Centre for Integrated Transport Innovation (rCITI) School of Civil and Environmental Engineering

University of NSW Sydney

T: +61 (0)2 9385 9504 E: [email protected]

Staff Webpage

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Welcome Back!

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The CVEN 4405 Teaching Team

Coordinator and Lecturer Prof. Michael Regan Professor of Human Factors Research Centre for Integrated Transport, UNSW Sydney E: [email protected]

Teaching Fellow Dr Prasannah Prabhakharan Research Fellow Research Centre for Integrated Transport, UNSW Sydney E: [email protected]

Demonstrator Mitch Cunningham E: [email protected]

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Review of last lecture

• Prasannah Prabhakharan’s lecture on road trauma:

• definitions • the problem • fatality and serious injury trends in Australia • Australia versus other countries • factors contributing to crashes • road user groups and road trauma • Crash codes • Crash prevention and mitigation • Case study

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This lecture - Overview

• Vision and driving

• The Visual field and driving

• Eye and Head Movement

• Conspicuity

• Legibility

• Visual disabilities

• Illumination

• Changing Illumination

• Glare

• Visual performance and accident rates

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Learning Outcomes

CLO1: Explain the fundamental principles of HF that can be used by civil and transport engineers to facilitate user- centred design

CLO2: Apply HF principles, methods and data to the design of road and traffic management systems

CLO3: Plan for the integration of HF into the design lifecycle of the road and traffic management system

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Vision – in Week 1 In Week 1 (Lecture 1b) of the course we learnt about human vision – its capabilities and limitations. We covered:

• how the eye works • the rods and cones of the retina • dark and light adaptation • visual movement perception • visual spatial perception • visual acuity • visual flicker • age and visual performance • colour vision

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Vision – This lecture In this lecture, we’ll learn about vision and driving, and how the traffic engineer can design the road environment to ensure that there is a safe correspondence between the driver’s visual requirements and the visual road environment.

Source: Mestre, 2002, p100; in Fuller & Santos, 2002

Vision and Driving

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Vision and Driving (1)

The driving task requires the driver to process a variety of ‘signals’ and other items of information from the road and traffic environment. (Ogden, 1996)

These signals and items of information can be:

• Visual (e.g. see traffic signs) • Auditory (e.g. hear ambulance) • Tactile (e.g. feel rumble strip on road) • Olfactory (e.g. small leaking fuel vapours) • Vestibular (e.g. feel acceleration, yaw etc)

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Vision and Driving (2)

• Most (around 90%) of the information that a driver has to process is visual

• It is important, therefore, for traffic engineers to have some understanding of the visual characteristics of the human visual system as they relate to driving.

Source: Hills, 1980; Lay, 1986, cited by Ogden, 1996

The Visual Field and Driving

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Visual Field and Driving (1)

• Only a very small part of the visual field is in clear vision at any one point in time

• Our eyes are in frequent motion, and the brain constructs what we see from a series of successive – sharply focussed - snapshots.

• In the process of doing this, the brain ‘fills in’ the connecting parts of the visual field.

Source: Cunningham, Regan & Cairney, 2017

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Visual Field and driving (2)

A visual signal has to be positioned within the driver’s visual field if it is going to be seen.

For a stationary road user (e.g. stationary driver or pedestrian), the following are field of view limitations (next slide)

Source: Ogden, 1996, p. 2.1.10

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Visual Field and Driving (3)

Stationary road users: • For reading, the visual field is narrow (3° - 10°)

• Objects located outside this field can, however, be detected:

• signs and signals within 10° - 12° of the line of sight can be seen and understood

• objects can be detected in peripheral vision: • to 90° left and right • 60° above the line of sight • 70° below the line of sight

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Visual Field and Driving (4)

As the vehicle speeds up, the eye focuses further ahead and so the visual field narrows.

e.g. at 30 km/h the lateral (left-right) angle of the visual field decreases to about 100° (compared to180° at rest)

e.g. at 100 km/h the lateral (left-right) angle of the visual field reduces to about 40° (compared to 180° at rest)

Source: Cole, 1972; cited in Ogden, 1996, 2.1.10

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Visual Field and Driving (5) If visual signals that need to be detected are not within this visual field, drivers will need to turn their head to look in the appropriate direction.

This means that, from a traffic engineering perspective, drivers must be given an indication and a motivation to turn their head to look in appropriate directions: e.g.

• by providing them with warning and control signs • by providing them with adequate sight distance at

intersections or railway crossings (sight distance is the length of roadway visible to a driver.)

Source: Ogden, 1996, p. 2.1.10

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Visual Field and Driving (6) Through design, the traffic engineer can direct a driver to detect an object located within the limits of peripheral vision – by making it sufficiently stimulating.

This stimulation can be provided by:

• movement of the object across the visual field (e.g. alternating lights at railway level crossing)

• brightness • pulsation (e.g. rotating beacon on an emergency

services vehicle).

Source: Ogden, 1996, p. 2.1.11

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Road Design Guidelines for Visual Field (1)

Ogden (1996) provides the following guidelines for traffic design:

1. “traffic signs and traffic signals must be within the driver’s field of view, having regard to the speed of travel

2. drivers need to be alerted to the presence of uncontrolled intersections, so that they will be prompted to move the head to seek vehicles on conflicting courses

Source: Ogden, 1996, p. 2.1.11

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Road Design Guidelines for the Visual Field (2)

• particular attention needs to be given to railway crossings with passive control only as trains will be less visible in peripheral vision

Source: Ogden, 1996, p. 2.1.11

Eye and Head Movement

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Eye and Head Movement (1) The main constraint on the rate at which drivers can gather visual information is the rate at which the eye can move from one object to another, and then re-focus.

Studies of eye movements reveal a maximum possible rate of about 4 fixations per second (Cole and Jenkins, 1982; cited in Ogden, 1996).

This rate cannot be sustained for a long period; around 2 fixations per second is the usual maximum rate for an alerted, busy, driver.

Source: Ogden, 1996, p. 2.1.11

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Eye and Head Movement (2) For normal driving, in which the driver is also attending to other driving tasks, a rate of 1.0 - 1.5 fixations per second is regarded as reasonable (Ogden, 1996).

For traffic design, therefore, it is necessary for traffic ‘signals’ to be separated in time.

Source: Ogden, 1996, p. 2.1.11

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Eye and Head Movement (3) If the vehicle is in motion, it is also necessary that traffic signals be separated in space.

e.g at a vehicle speed of 100 km/h:

• a driver would be able to view a ‘signal’ only once in every 20-28 m, assuming rate of information gathering of about 1.0-1.5 fixations per second.

Source: Ogden, 1996, p. 2.1.11

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Eye and Head Movement (4) • If traffic signals (traffic signs, traffic signals, etc) are

positioned closer than this, some will be missed - because the driver will simply be physically incapable of seeing them.

• If the traffic signals are provided at this spacing, and all of them are viewed by a driver, the may not be able to attend to other relevant traffic information, such as viewing other vehicles, pedestrians, etc.

• So when separating traffic signs and signals in space, it is important to take into account what else they need to attend to in the vicinity

Source: Ogden, 1996, p. 2.1.11

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Eye and Head Movement (5)

Drivers tend not to look very far ahead of their vehicle in order to seek out traffic signals which affect the driving task.

Cole and Jenkins (1982; cited in Ogden) found that traffic signs beyond 100 m are rarely noticed by drivers.

Although eye movements can be made over a field of view of around 50°, it is rare for that full range to be used.

Instead, drivers tend to move their heads to focus on each new object. Consequently, their eye movements are limited to about 15° left or right (Lay, 1986, cited in Ogden).

Source: Ogden, 1996, p. 2.1.11

Conspicuity

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Conspicuity (1)

The success of many traffic engineering measures and the safety and efficiency of the road traffic system depends largely on conveying information successfully to drivers to aid them in performing Brown’s (1986) functional driving activities.

The key needs of road users in relation to traffic control information are (Lay, 1986, p 424, 386; cited in Ogden, 1996):

• conspicuity (the ‘signal’ must be seen), • legibility (its message must be able to be read), • comprehensibility (the message must be understood), and • credibility (the message must be perceived to be true).

We will talk in this lecture about conspicuity and legibility, as they relate to vision; comprehensibility and credibility will be covered in the next lecture, as they relate to perception.

Source Ogden, 1996, p 2.1.13

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Conspicuity (2) • Signals that are conveyed to road users must be

conspicuous– that is, they must be able to be seen.

• Conspicuity refers to the efficiency with which a signal is capable of attracting attention (Hughes & Cole, 1984; cited in Theeuwes, 2002)

• The detection of a visual signal involves recognising it against its background.

• Conspicuity is affected by several factors (Cole and Jenkins, 1982, cited by Ogden, 1996, p. 2.1.13):

(See next slides)

Source: Ogden, 1996, p. 2.1.13

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Conspicuity (3)

• size (larger signs are more conspicuous) – e.g. stop signs and give way signs are large and red; street signs are smaller

• brightness (brighter signs are more conspicuous)

• boldness (larger letters are more conspicuous)

• edge sharpness (e.g. a line around the edge of a sign),

Source: Ogden, 1996, p. 2.1.13

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Conspicuity (4)

• contrast (high contrast, especially contrast in brightness, and against background) e.g. red sign is more conspicuous in areas with few red signs

• visual simplicity (a simple background makes a sign conspicuous)

• eccentricity (a traffic signal is unlikely to be detected if it is more than 6°- 7° away from the line of sight).

Source: Ogden, 1996, p. 2.1.13

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Conspicuity (5)

• People do not always look at the most conspicuous signal in the traffic environment

• Studies have shown that, when a signal is not relevant for the task they are performing, they are able to ignore it.

• However if it is conspicuous – and is also relevant for the task they are performing (e.g. route finding; a destination sign), the conspicuity is helpful because it attracts drivers’ attention quickly

Source: Theeuwes, 2002, p. 137; in Fuller & Santos, 2002

Legibility

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Legibility

• A visual traffic signal is legible if enough detail within it is sufficiently visible to allow its message to be interpreted (Lay, 1986, p 426; cited in Ogden, 1996).

• Increasing the size of a sign will increase its legibility distance and give a driver more time to observe and read the sign.

• Generally, signs which need to contain a lot of information need to be larger (e.g. direction signs).

Source: Ogden, 1996, p. 2.1.14

Visual Disabilities

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Visual Disabilities (1) In Week 1 of the course, we talked about colour vision deficiencies.

Recall that about 6.0% of males and 0.5 % of females in the population have colour impaired vision.

About 2.5 per cent of the adult male population has colour impaired vision, such that they cannot discriminate red, yellow and green (as in traffic signals) - or any three- colour combination

Source: Lay, 1976, p 325, cited in Ogden, 1996, 2.1.12

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Visual Disabilities (2)

• In addition, about 2.5 per cent of the adult male population has a reduced sensitivity to red – these people require about 4 times the colour intensity required by observers with normal colour vision

• Not sure what the corresponding figures are for females, but we can predict that the corresponding numbers will be smaller.

Source: Johnston and Cole, 1976; cited in Ogden, p. 2.1.12

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Visual Disabilities (3) • Some people experience blurred vision, as a result of near-

sightedness or other factors. As a result, their legibility distance is reduced. Legibility distance is the distance at which text on a traffic sign is legible (can be read).

• Around 5 per cent of the population is visually impaired with respect to detecting low luminance contrasts (e.g. can’t read information on traffic signs in low ambient light).

• Visual sensitivity declines with age and the traffic signal detection threshold of elderly drivers is about double that of younger drivers

Source: Lay, 1986, p 325; cited in Ogden, 1996, p. 2.1.12

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Visual Disabilities – Design Implications Ogden (1996) makes the following design recommendations for people with these visual disabilities:

• signal lanterns should be located in a standard fashion, with red on top, yellow in the middle, and green at the bottom; and the same applies to coloured turn arrows

• the intensity of traffic signals, and the actual colours used, need to be closely specified

• these considerations will also affect the size of traffic signs and the letters printed on them.

Source: Ogden, 1996, p. 2.1.13

Illumination

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Illumination (1) Illumination is… “the amount of light falling onto a surface. It refers to the lighting conditions in the environment and to how the objects are struck by photons, directly from light sources or indirectly from reflections by other objects” (Mestre, 2002, p. 103)

The human visual system is capable of operating over a huge range of illumination levels:

• from 0.75 x 10-6cd/m2 (a very dark night), to • 105 cd/m2 (a bright day at the beach) • this range - from darkest to brightest - varies by a

factor of over 1011.

Source: Mestre, 2002, in Fuller & Santos, 2002; Ogden, 1996, p. 2.1.12

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Illumination (2) The ability of the visual system to operate over this wide range is attributable to two factors:

• (a) The pupil of the eye can contract or dilate to let in more or less light.

• (b) After a period of relative dark, the receptor cells (cones) in the retina of the eyes take over.

Due to the cones, the eye can increase its sensitivity to light by a factor of about 107 over a period of only 30 minutes or so after exposure to dark.

(Cole, 1972, cited in Ogden, 1996, p. 2.1.12)

Changing Illumination

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Illumination (3) – Changing Illumination

• In a traffic stream, transient changes in illumination caused by exposure to relative light and dark as the vehicle progresses along the road are the relevant issue – e.g.in underground tunnels - rather than long term changes in ambient light levels e.g. in mines.

Source: Ogden, 1996, p. 2.1.12

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Illumination (4) – Changing Illumination

• When exposed to brightness after darkness, the pupil diameter contracts at a rate of about 3.0 mm/s (e.g. after exiting a tunnel)

• However, on exposure to darkness after brightness (e.g. entering a dark cave), it is much less responsive, dilating at about 0.5 mm/s

• As discussed in Week 1, the eye can adjust to sudden brightness much more rapidly than sudden dark.

Source: Cole, 1972; cited in Ogden, 1996, p. 2.1.12

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Illumination (5) (Changing) Ogden (1996) makes the following recommendations for the design of road tunnel illumination:

• in tunnels or long underpasses, artificial illumination should be provided at a higher level at the tunnel entrance – to facilitate dark adaptation.

• The lighting level can be reduced within the tunnel as the eye adjusts to the lower level of illumination

• There is no need for a higher level of illumination at the tunnel exit as the eye can adapt quickly to daylight.

Schrueder, 1991; cited in Ogden, 1996, p. 2.1.12

Glare

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Illumination (6) - Glare

• Another aspect of illumination that is important from a traffic engineering design perspective is glare - both from street lighting and from the headlights from oncoming vehicles.

• Glare is “produced by brightness within the visual field of view that is sufficiently greater than the luminance to which the eyes are adapted so as to cause discomfort, or loss in visual performance and visibility” (Sanders & McCormick, 1987, p. 411)

• Both glare from street lighting and from oncoming vehicle headlights can result in a decrease of visibility and discomfort to the driver.

Source: Ogden, 1996, p 2.1.12

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Illumination (7) - Glare

• People become more sensitive to the effects of glare as they get older, especially after age 60

• Glare sensitivity is one of the main reasons why elderly people have much less vision at night.

• Interestingly, blue-eyed people are more sensitive to glare than brown-eyed people. Can you guess why?

Ogden, 1996, p 2.1.12; Sanders & McCormick, 1987, p414

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Illumination (8) - Glare

Ogden (1996) makes the following design recommendations for minimising glare:

1. “Glare effects from street lighting can be kept to a minimum by reducing luminaire brightness, increasing mounting height, and increasing the background brightness.

2. Glare from oncoming headlights can be minimised by plantations or fencing in the median of divided highways.

3. Illuminating the roadway is also effective in reducing headlight glare since drivers do not have to use their headlight high beam.”

Source: Ogden, 1996, p. 2.1.12

Vision Performance and Accident Rates

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Visual Performance and Accident Rates (1)

• Previous research has shown that there are 4 measures of visual performance that are associated with poor driving records:

• dynamic visual acuity • static visual acuity • field of vision • glare recovery.

• Dynamic visual acuity is “the ability to distinguish detail when there is relative motion between the object and the observer.” (https://www.ucalgary.ca/FTWguidelines/content/visual- acuity)

Source: Mestre, 2002, in Fuller & Santos, 2002, p. 101

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Visual Performance and Accident Rates (2)

• Dynamic visual acuity is most closely and consistently correlated with poor driving record.

• Generally, however, there is little evidence of a direct relationship between poor visual performance aand high accident rates for young and middle-aged drivers.

• However, for the over 54 age group, dynamic and static visual acuity show a consistent relationship with accident rates.

Source: Mestre, 2002, in Fuller & Santos, 2002, p. 101

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Questions ?

Over to ….

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Required Reading

Ogden, K.W (2003). Human Factors in Traffic Engineering (Chapter 2.1). In Young, W., Ogden, K. W., & Taylor, S.Y (Eds). Traffic Engineering and Management (3rd Edition). Monash Institute of Transport Studies.

• Section titled “Visual Characteristics” (pp 2.1.10 to 2.1.17)

1. Austroads (2017). Austroads Guide to Traffic Management Part 13: Road Environment Safety (3rd Edition). Sydney, Australia: Austroads.

The following sections (each section is only around 1-page long): • 5.2.6 Traffic Controls • 5.2.7 Traffic Signals • 5.2.8 Traffic Signs • 5.2.10 Road Lighting

E- copies available via UNSW Library

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CVEN 4405 Human Factors in Civil and Transport Engineering

Term 3 2020 Week 4 - Lecture 2

STOP RECORDING

Prof. Michael Regan, PhD Research Centre for Integrated Transport Innovation

(rCITI) Room 112, Civil Engineering Building (H20)

E: [email protected]