ETSC Best in Europe Conference 2006

Changing Human Machine Interfaces

Towards the development of a testing regime

Samantha JamsonUniversity of Leeds

Current guidance on HMI• European Statement of Principles

(1999, updated 2005)

• System manufacturer guidelines “do not operate this system whilst driving”

• Drivers’ common sense…………

Need a test regime to provide objective guidance

The challenge

• To design a test regime that:– Is technology-independent, i.e. does not

depend on a particular technology being employed in a system design

– Uses safety-related criteria

– Is cost effective and easy to use

– Is appropriate for a wide range of HMI

– Is validated through real-world testing

A three year attempt…..• HASTE project (HHuman Machine uman Machine

Interface Interface AAnd the nd the SSafety of afety of TTraffic in raffic in EEurope)urope)

• Decide how to measure distraction

• Establish the effects of distraction on driving performance

• Use real tasks to validate the process

• Develop a draft test regime

Overall approach – Stage 1• Surrogate In Vehicle Information Systems (S-IVIS)

– One cognitive, one visual– Three S-IVIS levels

• Assessment methods– Simulator, Laboratory and Field

• Road– Urban, rural and motorway– Road complexity level

• “Average” vs older drivers

• UK drivers vs Portuguese drivers

17 experiments, 527 participants

Visual distraction task

Effects of visual distraction

• Fewer glances straight ahead• Lateral control deteriorates

• Speed reduction

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Cognitive distraction task(auditory)

• Participants’ task is to maintain a count of ‘target sounds’ presented within a list, keeping a separate tally for each target sound

• Performance is thought to deteriorate with an increase in the number of target sounds

Effects of cognitive distraction

• More glances straight ahead

• Improved lateral control• Poorer longitudinal control

Baseline Cognitive task

A misguided (?) conclusion……

• HMI that require cognitive/auditory attention are less distracting than visual ones

• Not only are they less distracting, but they improve driving performance (!)

Alternative explanation

• Narrowing of visual gaze

• Attentional processes also affected by distraction

• Late detection and poor identification of stimuli

– “I didn’t expect it,”

– “I looked but failed to see,”

– “I saw it too late.”

The HASTE draft test regime

• Driving in at least a medium-level driving simulator with a relatively small number of subjects (15 subjects are thought to be sufficient)

• A rural two-lane road driving situation and a duration of approximately one hour

• Assessment needs to take place at the level of specific tasks on the IVIS, since an IVIS may have a combination of comparatively easier and relatively harder tasks

• A small number of dependent variables (indicators) are sufficient. At the moment, a set of 5 indicators is recommended.

Suggested indicators

• Subjective rating of driver’s own performance

• Average speed• The proportion of high frequency

steering activity• The minimum time headway to a lead

vehicle.• Reaction time on Peripheral Detection

Task

Implications• The mode of distraction is important• Some variables are more sensitive than others• Some testing environments are more useful than

others – Rural road was most diagnostic in simulator

Motorway was most diagnostic in field• There could be implications for older drivers

– managing the trade-off between driving and secondary tasks

Meta analysis to obtain robust results on sensitivity, reliability, and consistency of effects, and their links to safety

www.its.leeds.ac.uk/projects/haste

Complementary methodologies

• A checklist could identify possible system design problems at a stage where they can still be corrected.

• Low cost simulators could be used in the early evaluation stage

• Some field trials may be necessary for older drivers (simulator sickness)

Changing HMIs – what are the options ?

Research outputs remain so Enforced by legislation

EU National

Issued as Commission Recommendation Adopted voluntarily, backed up by ISO Used as consumer information (P-NCAP)

– Not legally binding

(Not) The future