Challenges of Adequate Road Crossing Time for Older Persons: A Pilot Study in S ingapore

To the Editor: In many countries, older pedestrians struggle to cross the road within the standard time allowed. Singapore has recently initiated a “Green Man +” scheme that allows extra walk time for older pedestrians and people with disabilities. When one taps a registered card on a reader, the system will allow 3 to 12 seconds (average 5 seconds) of additional walk time. Although this promising initiative is currently being extended to 500 systems islandwide by 2014, it is unclear whether the extra walk time provided is appropriate. Previous studies on gait characteristics of older pedestrians consider only unloaded walking. In Singapore, many older adults provide care for young children and shop daily for groceries. Thus, there is a need also to consider crossing times when handling a stroller, shopping cart, and grocery bags. To facilitate future pedestrian crossing signal development, a pilot study was conducted to assess whether current crossings in Singapore provided sufficient time for pedestrians under various loading conditions and determine additional walk time (if any) required. Length of the crossing and duration of the steady (cross with care) and flashing (do not start to cross) walk signals were profiled at 198 pedestrian crossings in five districts with the highest proportion of elderly residents. In a laboratory, start-up times and walking speeds during simulated road crossing were measured in 52 healthy participants (aged 21–35, n = 20; aged 60–69, n = 17; aged ≥ 70, n = 15) under four conditions: unloaded, pushing a stroller loaded with 10 kg, pulling a shopping cart loaded with 15 kg, and carrying two bags each loaded with 2 kg. With the road and gait information acquired, the additional walk time needed in two scenarios was calculated: entering the road from stationary at the onset of the steady walk signal and entering the road as the walk signal starts to flash. When starting during the steady signal, young pedestrians and those aged 60 to 69 could cross comfortably at almost 99% of the crossings, whereas those aged 70 and older would struggle at up to 14.6% of the crossings, requiring up to 6 seconds (unloaded) to 8 seconds (loaded) of extra time. Entering the road at the onset of a flashing signal was more problematic because even young pedestrians would struggle at many crossings. Pedestrians in their 60s would fail at 18.7% of the crossings while unloaded and up to 34.8% if loaded. Pedestrians aged 70 and older would struggle at more than 50% of the crossings and would have failed at 100% when pulling a shopping cart in one district. Most crossings can be improved by having up to 10 seconds longer flashing time, although some need as much as 30 seconds more (Table 1). In spite of the fact that most crossings provided sufficient time when starting during the steady signal, the flashing time was often too short, suggesting a need to revise the current proportion of the steady and flashing signals. Another study in Dublin also reported insufficient time when starting during the steady signal in 30% of the crossings, compared with 96% for starting once the signal had started to flash. It is legal for pedestrians to start crossing at the onset of the flashing signal, so they should be allowed sufficient time to cross. Until the current system is revised, older adults are advised to cross only at the beginning of a steady walk signal. The “Green Man +” allows an extra 3 to 12 seconds for pedestrians aged 60 and older. This implementation is consistent with the findings that pedestrians aged 70 and older would need up to 6 to 8 seconds longer, although those aged 60 to 69 seem not to need extra time if they start when the signal is steady. Similar situations were reported in Dublin, with only pedestrians aged 80 and older having insufficient times to cross wider roads. Given the challenge of balancing between allowing adequate crossing time and keeping good vehicular flow, activating the “Green Man +” for pedestrians who do not need it may cause unnecessary delay in traffic. Walk time may have been underestimated because the participants were healthy and conditions were favorable. Nevertheless, the need to increase the length of the flashing signal time and that the “Green Man +” may not be necessary for healthy pedestrians in their 60s was demonstrated. With the advancement of technology, it may soon be possible to store personalized gait data on a sensor that can activate the pedestrian crossing system to cater to individual needs.