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Table 4 Input parameters for estimation of intervention effect, mean value and 95% uncertainty intervals

From: Obesity-related health impacts of fuel excise taxation- an evidence review and cost-effectiveness study

Parameter Mean values and 95% UIa (where applicable) Sources and assumptions
Cross price elasticity for PT with respect to fuel price 0.07 Derived increase in the prevalence of PT commuting of 0.61% [38]. Modelled to PA/BMI effect (Appendix 3). Assumed all new PT users were previous car drivers, a reasonable assumption given the high prevalence of driving to work in Australia [38].
Average annual retail fuel price (national, metropolitan)
(cents per litre)
125.39 cents
(95% UI 124.95–125.86)
Sampled from a gamma distribution, from national metropolitan fuel price [102].
Marginal METb value for walking to access PT 2.5
(95% UI 0.7–6.4)
MET value for walking to access PT 3.5 from Ainsworth et al. 2011 [81], adjusted for inactivity. Sampled using a lognormal distribution (stdev 1.6 from Gotschi et al. 2015 [103]).
Average distance a person will walk to access PT (metres) 400 Based on ‘rule of thumb’ planning guideline for distance walked to bus/tram access points [104, 105].
Comfortable gait speed (cm/s) Males
18-29y = 139.2
(95% UI 110.5–172)
30-39y = 145.7
(95% UI 128.4–164.2)
40-49y = 145.6
(95% UI 115.6–180.4)
50-59y = 139.5
(95% UI 100.5–192.2)
60-64y = 136.3
(95% UI 100.9–179.7)
Females
18-29y = 140.3
(95% UI 109.3–177.4)
30-39y = 140.8
(95% UI 117.5–166.9)
40-49y = 139.2
(95% UI 111.5–172.1)
50-59y = 139.5
(95% UI 112.2–170.8)
60-64y = 129.6
(95% UI 90.8–172.7)
Sampled from a lognormal distribution, taken from estimates from Bohannon 1997 [106]. Using average distances and gait speeds this results in an average increase in walking to access PT of 18.9 min per day in men and 19.2 min per day in women. This falls within the range summarised by Rissel et al. [30] of 8 to 33 min PA associated with PT use.
Number of weeks of intervention effect (averaged over year) 49
(95% UI 46–52)
Sampled from a uniform distribution based on estimate of number of working weeks per year for full-time workers.
  1. Table notes: a95% uncertainty interval (UI) based on 2000 simulations. b = Metabolic equivalent task (MET) value defined as the ratio of activity specific metabolic rate to standard resting metabolic rate of 1.0 [81]. ABS Australian Bureau of Statistics, AUD Australian dollars, cm/s centimetres per second, PA physical activity, PT public transport, RIS regulatory impact statement, SA sensitivity analysis, VISTA Victorian Integrated Survey of Travel and Activity, Y years of age