Elsevier

Preventive Medicine

Volume 47, Issue 3, September 2008, Pages 270-272
Preventive Medicine

Modelling effects of stair width on rates of stair climbing in a train station

https://doi.org/10.1016/j.ypmed.2007.12.008Get rights and content

Abstract

Objectives

Commuters leaving a station often choose the stair as a quicker exit than the escalator. This paper models the effects of speed leaving the station and stair width on choice of the stairs or escalator.

Methods

Aggregated data from previous studies (n = 82,347) revealed a plateau at about 45% stair use as the number leaving each train rose. Subsequently, the time taken by passengers on the stairs and escalator was measured in a station in Birmingham, UK in 2007 (n = 5848). The resulting transport rates (passengers s 1) for stairs and escalators at the average commuting traffic were used to estimate the effects of increases in stair width on choice of the stairs.

Results

Average transport rates were higher for the escalator (0.93 ± 0.33 passengers s 1) than the stairs (0.58 ± 0.24 passengers s 1). Modelling of the effects of transport rate with multiple regression suggested 40.1% of passengers would use the stairs, a figure close to the observed rate. Using similar calculations, a doubling of width of the stairs could result maximally in a 17.2% increase in stair use.

Conclusions

Changes to the width of stairs could produce a permanent increase in lifestyle physical activity immune to the effects of time on healthy intentions.

Introduction

Accumulation of stair climbing can contribute to increased energy expenditure during daily living. Importantly, prompting pedestrians to choose the stairs over the escalator is a consistently effective intervention (Eves and Webb, 2006, Eves, 2007). Nonetheless, successful prompting requires a willingness by pedestrians to improve their health; those not considering any change in their behaviour, i.e. pre-contemplators, rarely report even seeing the prompt (Kerr et al., 2000). Additionally, effects of prompts are reduced over time (Kerr et al., 2001a), analogous to the return to less healthy behaviour that undermines individual approaches to behaviour change (Dishman, 1988). In contrast, changes to the built environment that promote active travel, unlike interventions that require healthy intentions, may produce permanent changes in behaviour (Sallis et al., 2004).

Studies of stair climbing on public access staircases consistently demonstrate increasing stair use as pedestrian traffic rises (e.g. Kerr et al., 2001a, Kerr et al., 2001b, Kerr et al., 2001c, Webb and Eves, 2007). When access to the escalator is blocked at high traffic volumes, some pedestrians choose the stairs as the faster route to their destination (Kerr et al., 2000, Kerr et al., 2001b). For stations, pedestrian flow is pulsatile with intermittently high rates of traffic as each train disgorges its contents. This simultaneous exit of passengers elevates rates of stair climbing (19.2%: Eves et al., submitted for publication) compared to shopping malls where traffic is spread more evenly (5.5%: Eves and Webb, 2006).

Fig. 1 depicts the percentage stair climbing for different numbers leaving trains between 8.15 and 9.45 am at Snow Hill station, Birmingham, UK in 2006–2007 (total n = 82,347: Eves et al., submitted for publication; Olander et al., in press).

As can be seen, a negatively accelerated function reaches a relative plateau at about 45% for more than 200 passengers. This plateau reflects saturation of the stairs and escalators such that both exit routes reach maximum capacity. The plateau's location is a function of the capacity of the stairs to remove passengers from the station, with contributions from speed of transit and stair width. For escalators, the speed of ascent is a fixed value whereas the speed of stair ascent is individually chosen. The second variable, width of each method of ascent, determines the maximum number of pedestrians on each step of the stairs and escalator. Thus rates of transport of passengers out of the station are a function of the average speed and width of each method of egress. Wider stairs have already been linked to greater stair use in buildings (Nicoll, 2007). This paper uses transport rates for passengers leaving a station to model the effects of an increase in stair width on stair climbing during the rush hour.

Section snippets

Methods

Observations (n = 5848) were made 8.00–10.00 am on three weekdays at Snow Hill station, Birmingham, UK in 2007. At 1.94 m, the stairs were wider than the escalator (1.24 m), with three passengers step 1 on the stairs compared to two on the escalator. Two inconspicuous observers positioned near the bottom of the stairs and escalator counted the number of passengers using each method of ascent and timed the total duration of the ascent from the first passenger stepping on the bottom step until the

Observed transport rates for the escalator and stairs

Fig. 2 depicts the passengers s 1 on the escalator and stairs plotted against the number of passengers leaving each train. Escalator transport rates were higher (mean = 0.90 ± 0.33 passengers s 1) than the stairs (mean = 0.58 ± 0.24 passengers s 1; t38 = 12.56 p < .001) consistent with reports of escalator choice as a faster option (see Kerr et al., 2001c).

For the escalator, multiple regression with linear and quadratic components fitted the data well (R2 = 0.921 p <.001), with transport rate described by the

Discussion

The predicted stair use based on transport rate (40.1%), while close to the observed value (45%), nonetheless underestimated it. Stair climbing was more prevalent than predicted by transport rate alone. As noted earlier, stair climbing rates in shopping malls where pedestrian traffic has less effect are 5.5% (Eves and Webb, 2006), suggesting some pedestrians may choose the stairs at most opportunities. Thus effects of transport rate, coupled with a preference for stairs in a minority, would

Conclusions

Commuters try to leave stations by the quickest route. Increases in stair width could harness this rush to work in the fight against obesity. Changes to stair width would have permanent effects on lifestyle physical activity, maximally being almost three times those achievable with health promotion messages for a doubling of width.

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