Keywords

1 Introduction

The global population of people aged 65 and older is growing at a fast rate. As population aging becomes a trend in the 21st century, the safety and mobility of all elder road users deserves more attention. In Taiwan, senior citizens accounted for 11 percent of the total population; the country is now moving from an aging society to an aged society [1]. The most common motor vehicles in Taiwan are scooters. Scooters are allowed on most roads (except highways and expressways). Almost one-half of the total population owns a scooter and 70 % of the registered vehicles are scooters [1]. The dense population and limited living spaces make scooter riding a convenient way to travel in and around the cities. The costs of riding scooters (including tax, gas, and maintenance) are lower than those of driving cars, which makes scooters become popular among adults and the elderly.

The patterns of riding a scooter and driving an automobile are quite different. Scooter riding requires less mental resources than automobile driving. However, the risks for riding scooters are much higher than those of driving automobiles [2]. According to You et al. [1], accidents involving scooters contribute to more than 80 % of fatalities in traffic accidents in Taiwan, resulting in more than 2,000 deaths annually. The literature indicates that elderly people are more likely to be involved in crashes, and they are more likely to suffer serious injuries in crashes [3]. The probabilities and consequences of traffic accidents are both higher on elderly people than on young people [2].

The main causes of higher risks of traffic accidents among senior road users include the decreased visual attention, and physical and functional capabilities [4]. Horberry et al. [5] found that, compared with young adults, elder adults are more easily distracted by the surroundings. Braitman et al. [6] and Fofanova and Vollrath [7] also found that elder drivers are less able to deal with complicated road conditions than young drivers. As to the riding behavior, senior road users are more likely to fail to give right of way (due to attention degeneration), leading to traffic collisions [8].

Studies indicated that in order to drive safely senior road users (being aware of their limitations) tend to compensate for their physical degeneration by driving more slowly, driving less at night or during bad weather, or keeping a safe distance behind the vehicle in front [9, 10]. However, these strategies may not always be sufficient to avoid risks and hazards on the road. Traffic accidents still happen constantly. To further lower the probability of traffic accidents, research and technological efforts were made in the industry and the academia. For example, Vashitz et al. [11] developed innovative in-vehicle displays that provide highly informative road safety information to improve traffic safety, especially in tunnels; Yu et al. [12] proposed the use of smart automotive lighting in vehicle safety systems that can detect potential risks in advance and provide early warnings to drivers. In fact, what has been most emphasized was related to automobile safety, not including scooter safety.

In Taiwan, scooters are allowed to travel on the right/slow lanes, but not on the left/fast lanes. It is common that automobiles double park temporarily on the roadside with car signal lights flashing (for quick paying bills/buying groceries etc.). However, this occupies a certain portion of the road/street, oftentimes forcing scooter riders to change the lane to pass through temporarily double parked automobiles. The problem is that traffic accidents/collision could happen during the lane changing if the trailing vehicles cannot react quickly enough due to high speed. The problem may get worse if the involved scooter riders are the elderly. The speed of the elder scooter riders typically is relatively slow, but elder scooter riders are more vulnerable to be hit by any vehicles when changing the lane.

Therefore, to enhance the safety of elder scooter riders, in this study, we developed a hazard warning helmet that can reduce risk taking behavior when elder scooter users attempt to pass through double parked vehicles (considered obstacles in front). In addition, we demonstrated the effectiveness of our helmet through an observational study. This work has contributions on (1) lowing traffic collision rates, (2) helping elder scooter users be more aware of hazards in the surroundings, and (3) improving elder scooter users’ risky behavior.

2 Design and Development of the Hazard Warning Helmet

The hazard warning helmet design was inspired by the fact that elder scooter riders might be hit by approaching vehicles from the back after being forced to change the lane (for passing through double parked automobiles on the roadside).

As shown in Fig. 1, the helmet consists of four components: (1) LED lights attached to the front end of the fit padding inside the outer shell (to the back of the helmet face shield); (2) The Arduino UNO microcontroller board attached on top of the outer shell of the helmet; (3) two ultrasonic sensors attached to the upper-front and the back of the helmet.

Fig. 1.
figure 1

Design of the hazard warning helmet

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The upper-front ultrasonic sensor is designed to detect double parked vehicles/obstacles (or traffic cones) standing in the way of a scooter rider. As soon as an obstacle is detected, the upper-front ultrasonic sensor triggers the ultrasonic sensor in the back of the helmet that identifies whether or not there is any moving vehicle approaching the scooter rider from behind. As long as the ultrasonic sensor senses any approaching vehicle, the LED lights will be turned on.

We set the sensing distance of the upper-front ultrasonic sensor to be 17.2 meters. The rationales are: (1) the time required for young adults to respond to a lead car’s brake lights is about 1.25 s, and elderly people generally respond 0.3 s more slowly than young people [13]; (2) the average speed of elder scooter riders on the road is 40 km/hr. (from our pilot observations of six elder scooter riders on differing road intersections).

The ultrasonic sensor in the back is used to detect the “speed” and “distance” of any approaching vehicle coming from behind. As long as the distance of the approaching vehicle to the scooter is equal or smaller than the minimal required distance for stopping a vehicle, the ultrasonic sensor would turn on the LED lights. If the speed of an approaching vehicle is relatively high, the LED lights would flash quickly. Given that the human perception-brake reaction time is 1.25 s [13], the minimal required distance for stopping a vehicle can be obtained by detecting the “relative speed” of the approaching vehicle to the elder scooter rider. In addition, the benefit for placing the LED lights on the front end of the fit padding is that the red warning signal can be easily noticed by the scooter rider’s eyes.

3 Methods

An observational study was conducted to evaluate the effectiveness of the proposed hazard warning helmet.

3.1 Participants

Convenience sampling and snowball sampling were used by visiting the community centers in Tainan City, Taiwan. A total of five volunteering male elderly participants (over 65 years old) were recruited. All participants had ridden scooters on a daily basis and had more than 5-year experience of riding scooters. In the study, no monetary rewards were provided to the participants.

3.2 Equipment and Variables

The equipment included an open face helmet (with a face shield) and our proposed hazard warning helmet. The independent variable was helmet design (a conventional design vs. our proposed design). The dependent variable was behavioral reactions to double parked vehicles.

3.3 Procedure

At the beginning of the study, participants were given the instructions and explanations of the features of our proposed helmet. This study adopted a within subject design. Participants were required to experience both of the helmets (the conventional helmet and the hazard warning helmet). They were asked to wear the helmets respectively and ride their scooters in their pace to pass through 50 obstacles (i.e., double parked vehicles) along the roadside. The obstacles in this study were defined as temporarily double parked automobiles or traffic cones on the roadside, or any slow moving vehicles (including cars, scooters, and bicycles). Because these types of obstacles were common in Taiwan, this study did not manipulate their locations or appearances on the road.

This study selected a busy road (in Tainan City, Taiwan) with a total of six lanes long enough (about 12 km) for experiencing 50 obstacles. All participants were required to begin their riding tasks at the same designated location. The study was conducted between 2 to 5 pm to avoid the rush hour so that participants’ true riding and passing through behavior would not be affected by slow traffic.

In the study, there was one experimenter sitting behind every participant, riding with the participant, and counting the number of obstacles. The experimenter carried a wood board for recording the behavioral reactions of every participant when they faced obstacles. In this study, without vehicles approaching the participants from behind, the obstacle would not be counted and the participant’s behavior would not be recorded. As soon as a total of 50 obstacles were recorded, the experimenter would notify the participants and let them know they had completed the task.

A Wizard of Oz experimental technique was used where participants interacted with the provided hazard warning helmet that they believed to be autonomous in showing warning signals. The warning signals, in fact, were provided by the experimenter (sitting in the back) if he/she saw any vehicles behind was approaching when participants faced obstacles.

In addition, in order to identify participants’ true behavior when interacting with obstacles, the experimenters did not let participants know what behavior we were particularly looking for in the study. However, after completing the riding task, participants were informed about the details of the observational results. Participants had the right to withdraw. They could also determine if the observed data could be used for this study.

4 Results and Discussion

Results of the study identified four types of behavioral reactions to roadside double-parked vehicles: (1) reducing speed (without looking back) to pass through, (2) reducing speed and looking back before passing through, (3) looking in the side-mirror before passing through, and (4) passing through without taking precaution.

As shown in Table 1, it appears that when seeing obstacles or double parked vehicles, participants generally passed them through directly no matter which helmet they wore, which accounts for 66 % of all behavioral reactions when wearing our proposed helmet and 91 % of all behavioral reactions when wearing a conventional helmet. Only few participants (no matter which helmet they wore) would look back or look in the side mirror to prevent being hit by approaching vehicles.

Table 1. Participants’ behavioral reactions to and the corresponding # of obstacles (mostly double parked vehicles)
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Table 1 also reveals that, except passing through without taking precaution (considered risky behavior), most behavioral reactions (three out of four) were all related to reducing speed to avoid possible collisions. However, the percentages of them were relatively low (mostly less than 25 % no matter which helmet was worn). This suggests that safety awareness was poor among elder scooter riders and thus road safety education is necessary for elder scooter riders. Also, warning design and/or safety measures should be in place to help elder scooter riders avoid risks and hazards on the road.

Figure 2 compares the two helmet designs on participants’ behavioral reactions when interacting with obstacles/double parked vehicles. From Fig. 2, participants wearing our proposed helmet, compared with those wearing a conventional helmet, were more likely to reduce speed of their scooters when passing through obstacles. Moreover, participants wearing our proposed helmet were less likely to pass directly through obstacles/double parked vehicles than those wearing a conventional helmet. The results provided empirical evidence on the effectiveness of our hazard warning helmet in (1) promoting safe riding behavior, (2) inhibiting unsafe riding behavior, and (3) avoiding fast approaching vehicles. It is expected that elder scooter riders wearing our proposed helmet will ride more safely on the roads.

Fig. 2.
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Comparisons of two helmet designs on participants’ behavioral reactions when passing through double parked vehicles

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5 Conclusions

The purpose of this study was to develop and evaluate a hazard warning helmet that is aimed to help the elderly avoid traffic collisions and accidents. Our proposed helmet consists of four hardware components (the LED lights, the Arduino UNO microcontroller board, and two ultrasonic sensors). This innovative helmet provides visual warnings of fast approaching vehicles when elder riders pass through double-parked vehicles. An observational study was conducted to evaluate the effectiveness of the proposed helmet design. Five elderly participants participated in the study. They were asked to wear our proposed helmet and a conventional helmet respectively to interact with 50 roadside obstacles (mostly double parked vehicles). Results of the study showed that participants wearing our proposed helmet were (1) more likely to reduce speed and (2) less likely to directly pass through double parked vehicles without taking precaution.

Our work demonstrated that our innovative hazard warning helmet is effective in (1) promoting safe riding behavior, (2) inhibiting unsafe riding behavior, and (3) avoiding fast approaching vehicles from behind. Our study found that elder scooter riders tend to have risk taking riding behavior. Road safety education is needed (for example, through posters and social media and community networks, etc.) to enhance safety awareness among elder scooter riders. In addition, from the perspective of product design, designers should put more emphasis on designing products not only to improve the overall wellbeing, but also the health and safety of the elderly.

Our society is stepping into a digital and aging society. Leveraging the power of technology to develop senior-friendly products and devices should become an important consideration for all designers. This study is limited by the number of participants, culture, traffic conditions, environment, and ambient situations (e.g., noises and lighting). More in-depth investigations are required to verify the efficacy of the proposed helmet design in avoiding traffic collisions and hazards. Nevertheless, the results of this study provided insight into designing warning signals for scooter riders.