DO FUNCTIONALLY FIT ELDERLY COMMUNITY-DWELLING SUBJECTS HAVE ENOUGH TIME TO SAFELY CROSS THE ROAD?

摘要

Elderly people are the most vulnerable group in urban traffic and a large proportion of them are as pedestrians victims of traffic accidents. The majority of these happen while crossing the road. Crossing a busy road at an intersection with traffic lights or without them is a typical dual task condition requiring a motor task i.e. walking and a cognitive task such as monitoring traffic. The purpose of present study was to compare the walking speed and the related spatio-temporal gait variables of falters and non-fallers in three walking conditions against the speeds required by regulations in Slovenia for safe street crossing. To assess the spatio-temporal characteristics of gait we used a 7m instrumented walkway. The general results showed that the spatio-temporal gait parameters did not differ between the two groups at the self-selected speed. But as soon as a constraint, such as fast walking speed, was imposed on the subjects the differences between the groups became evident. Falters demonstrated a significantly slower mean gait velocity and shorter stride length while the cadence and the base of support did not differ between the two groups. In dual task conditions the difference between the two groups reached 25 percent. The fallers group gait velocity dropped to 0.99 m/s. The observed walking speed was slower than considered by the guidelines for the design of traffic light equipped road crossing. In conclusion, the results of walking speed under dual task conditions could be a useful parameter for planning of optimal pedestrian crossing in urban areas. These results will serve for the design of a population based study in Ljubljana.%Starostniki so najbolj ranljiva skupina v mestnem prometu, saj predstavljajo velik delež med udeleženci prometnih nesreč. Večina teh se zgodi med prečkanjem ceste kar je tipičen primer dvojne naloge kjer oseba poleg gibalne naloge (hoja) opravlja tudi kognitivno nalogo kot je na primer opazovanje prometa. Namen pričujoče študije je bil primerjati hitrosti hoje, in z njo povezanih prostorsko-časovnih parametrov, oseb, ki so v času enega leta padli in tistih, ki se jim to ni zgo-dilo, v treh različnih pogojih (normalna in hitra hoja ter dvojna naloga), ter te rezultate primerjati s priporočili za izgradnjo cest v mestu Ljubljana. Parametre hoje smo izmerili s pomočjo elektronske sedem metrske merilne preproge. Rezultati so pokazali, da se prostorsko-časovni parametri hoje med obema skupinama niso razlikovali kadar so osebe lahko same izbrale hitrost hoje. Kakor hitro pa se je pojavila dodatna zahteva, kot na primer zahteva po zelo hitri hoji, pa se je nastala razlika med obema skupinama. Osebe, ki so padle so v povprečju hodile počasneje in s krajšimi koraki, kakor tiste, ki niso padle vendar pa se širina podporne ploskve med skupinama ni razlikovala. V primeru dvojne naloge sta se skupini med seboj razlikovali celo za 25%, pri čemer se je hitrost hoje oseb z izkušnjo padca zmanjšala celo na 0,99 m/s. Izmerjena povprečna hitrost hoje je bila tako nižja od hitrosti, ki jo navajajo priporočila za načrtovanje semaforiziranih prehodov za pešce. Iz te raziskave zaključimo, da so lahko rezultati meritev parametrov hoje v primeru dvojne naloge pomemben parameter za načrtovanje prehodov za pešce v mestnem okolju. Naši rezultati bodo uporabni za načrtovanje populacijske študije v Ljubljani.