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Duty, travel, and commute

Planners and safety teams often need to separate duty (paid or scheduled work), travel (journeys to and from work), and commute (regular home-to-base travel). These terms are used differently across sectors, contracts, and fatigue models.

Confusing them can lead to underestimating total fatigue burden — or incorrectly assuming all journey time is paid working time.

This page explains the concepts for fatigue planning and risk assessment. It is not legal advice on working time, pay, or employment rights.

Section titled “Four related concepts”
ConceptPlain-English meaningTypically includesFatigue relevance
DutyPlanned work period at site or operational locationOn-duty tasks, on-site breaks, operational overheadCore work exposure — shift timing, duration, breaks
Travel (out / back)Journey between origin and work locationOutbound and return legs to site, depot, or workfrontAdds wakefulness and stress; may limit recovery
CommuteRegular travel between home (or usual base) and workplaceDaily or routine journey patternsCumulative burden; quality of rest before/after duty
Door-to-door timeTotal elapsed time from leaving origin to returningTravel out + duty/work + travel backWhole-journey fatigue exposure for planning

These definitions are not universal. Your organisation’s policy, contract, and sector standards may define terms differently.

Duty

Section titled “Duty”

Duty usually means the period when a worker is required to be at work performing operational tasks — including breaks taken during the shift.

For fatigue planning, duty captures:

  • Shift start and end times
  • Duration and breaks within the shift
  • Workload and task demand during the period

Duty length alone does not always describe the full fatigue picture. A worker may have a standard eight-hour duty but face a long journey before and after.

Travel

Section titled “Travel”

Travel covers journeys to and from the work location. In field operations, rail possessions, construction sites, and utilities call-outs, travel can be substantial and variable.

ORR guidance on managing rail staff fatigue notes that time spent travelling to and from work does not provide rest in the same way as time at home — especially when staff drive themselves. Travelling as a passenger reduces road risk to others but does not offer the same sleep opportunity as being at home in suitable conditions.

Travel may be:

  • Scheduled and predictable — regular depot-to-site routes
  • Variable — disruption, diversions, or remote locations
  • Split across days — outward travel one day, return later (e.g. with accommodation)

Whether travel is counted in a fatigue model, working time calculation, or paid hours depends on policy and context — not a single UK-wide rule for all workers.

Commute

Section titled “Commute”

Commute usually means regular travel between home (or a usual residence) and the normal place of work.

Commute matters for fatigue because:

  • It extends the wakeful period before duty starts and after duty ends
  • Long commutes reduce time available for sleep and recovery
  • Driving while fatigued after a night shift or long duty is a recognised risk

HSE RR446-based fatigue models may treat commute differently from duty — for example by applying baseline commute assumptions or recording excess travel above a baseline. Methodology varies; inputs should match your organisational approach and be documented.

Commute is not always working time for pay or working time law purposes. For fatigue risk assessment, it may still be relevant to ask whether the total burden before and after duty is manageable — see door-to-door time.

Door-to-door time

Section titled “Door-to-door time”

Door-to-door time is the total elapsed period from leaving an origin (home, hotel, depot) to returning after work — typically:

Door-to-door = travel out + duty + travel back

It is a useful fatigue planning lens for mobile and site-based workforces. See the dedicated door-to-door time guide.

Door-to-door time is distinct from:

  • Duty length alone
  • Paid hours on timesheets
  • Working time as defined in regulations (which may exclude some travel)

How definitions vary

Section titled “How definitions vary”

The same journey may be classified differently depending on context:

QuestionWhy it varies
Is travel part of duty?Employment contract, sector practice, client requirements
Is commute included in FRI calculations?Organisational policy and model configuration
Does working time law count travel?Role, sector exemptions, and whether travel is “working time” in law
What origin is used (home vs accommodation)?Multi-day assignments, rail possessions, remote sites

Organisations subject to contractual fatigue standards — for example on some rail infrastructure work — may need to consider definitions in those standards. Those requirements apply to relevant contracts, not universally to all UK employers.

Practical questions for assessment

Section titled “Practical questions for assessment”

When reviewing a role or roster, consider:

  • How long is the duty itself?
  • How much travel is typical before and after duty?
  • Is the worker driving or a passenger?
  • Does the worker stay in accommodation — changing which leg of travel applies on which day?
  • Does the total door-to-door burden allow realistic sleep and recovery?
  • Do actual journeys match what was planned? If not, review planned vs actual fatigue exposure

These questions belong in a fatigue risk assessment — alongside shift timing, consecutive duties, and workload.

Relationship to FRI methods

Section titled “Relationship to FRI methods”

Fatigue risk index (FRI) methods based on HSE RR446 primarily model roster and duty inputs. Some organisational policies extend assessment to include travel or commute data.

Model outputs depend on inputs and configuration. Poor travel assumptions produce unreliable scores — see limitations of fatigue models.

For how FI and RI interpret duty timing, see Fatigue Index vs Risk Index.

What this page does not cover

Section titled “What this page does not cover”

This page does not:

  • State whether travel or commute is paid working time — that depends on employment law, contract, and role
  • Provide legal advice on Working Time Regulations compliance
  • Reproduce industry-standard threshold matrices
  • Define Network Rail or other contractual numeric limits

Seek competent advice for pay, working time, and contractual compliance questions.

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References

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