1. Next Generation Fatigue Models
Jessica Paterson
Post-Doctoral Research Fellow
University of South Australia

2. Fatigue Risk Management
Hazard assessment Error Trajectory Control Mechanism
Adequate Prescriptive HOS rule
sleep opportunity? Fatigue modelling
Level 1
Adequate Personal PSWM
Level 2
sleep obtained? Sleep diaries
Are there fatigue- Level 3 Subjective reports
Fatigue models measure the sleep opportunity
related behaviours ? Symptom checklist
associated with a roster, not fatigue.
Have there been Level 4 Analysis of errors and

3. Fatigue Modelling Tools
Shift Start and Finish Time
Shift Timing
Shift Duration
Work History
Circadian ‘Value’ of a Rest Period
Fatigue score of between 80-100 currently used as cut-off.
Comparable to BAC .05

4. Prescriptive Rules
Permitted
and Safe
Not-
Permitted
and Not
Safe

5. Prescriptive Rules
Permitted
and
Permitted
Not Safe
and Safe
Not-
Not-Permitted Permitted
and and Not
Safe Safe

6. Prescriptive Rules
Permitted
Permitted
and Unsafe
Not Safe
and Safe
Not-
Not-Permitted Permitted
Inefficient and and Not
Safe Safe

7. Fatigue Models
Green Yellow Red Black

8. Fatigue Models
Green Yellow Red Black
Permitted
and Safe
Not-
Permitted
and Not
Safe

9. Fatigue Models
Green Yellow Red Black
Permitted Permitted
and Safe and Unsafe
Not Safe
Not-Permitted Not-
Inefficient and Permitted
Safe and Not
Safe

10. Next Generation Fatigue Models
Permitted
and Safe
Not-
Permitted
and Not
Safe

11. Next Generation Fatigue Models
Permitted Permitted
and Safe and Unsafe
Not Safe
Not
Inefficient Permitted Not-
And Safe Permitted
and Not
Safe

12. To enhance the sleep/wake/work database that
underpins fatigue modeling algorithms
Demographic Information
Sleep, Work and Fatigue diaries
Activity Monitoring
300 Rail Employees
Multiple Workgroups
Drivers and Support Crew
Tradespeople
Management
4000-5000 days and nights of data

13. O O O O

14. O O O O

16. The Final Product
A next generation fatigue modelling tool which is:
- Representative of different social and domestic profiles
of various workgroups
- Provides a indicator of the proportion of employees
that fall in the low, moderate or high fatigue category
relative to their working time

17. The Final Product
A more scientifically defensible approach to Fatigue
Management in the Australian Rail Industry
…a safer and more efficient railway.