Ayanori Sato 1), Nicholas Bowler 2) 1 Railway Technical Research Institute 2 RSSB 1

RTC Risk Triggered Commentary driving (RTC) RTC is a rehearsal technique where train drivers speak aloud what they are thinking while driving. This technique was produced in the UK around The effects of RTC Helps prevent the user forgetting to do something (prospective memory error) Helps keep concentration levels raised 2

Situations for using RTC No.SituationPurpose 1On approach to a restrictive signal Reduce likelihood of a SPAD. 2On approach to a speed restriction Reduce likelihood of speeding 3Checking the route indictor is displaying the correct route Reduce likelihood of continuing on the wrong route. 3

P & C Point and Call Check (P & C) P & C is a check method that originated in Japan. Point to target and call its state loudly. P & C is another rehearsal technique. The effects of P & C Preventing misperception Preventing action slip Keep concentration level STOP! 4

Situations for using Point and Call checks Train Drivers check: Traffic Signal Timetable Time Brake Gauge 5

Purpose of this research Both RTC and P & C are rehearsal techniques used to prevent human error. Their methods of use are similar. However, few studies have been conducted investigating how to use these techniques effectively. Purpose This study investigated how to use these techniques effectively using train simulators in the UK. 6

RTC: the case of SPADs In some cases, RTC is used for preventing SPADs 7 train Platform Event Pass another train Track maintenance worker Driver Reduce speed Respond to AWS Memorize red signal Driver Reduce speed DRA Forgetting the red signal Event Conversation with passenger 20 40

The Case of using RTC 8 train Plat home Event Another train Track maintenance worker Event Conversation with passenger Event Driver does not accelerate Driver Reduce Speed Respond to AWS train Driver Reduce Speed DRA train Comment train Comment 20 40

Investigating the different methods of using RTC It is unclear how to use RTC effectively. In this research, two methods of using RTC were investigated. 1. Continuously repeating the commentary This method required participants to speak aloud “next signal is red” every 2 seconds, after passing the yellow signal. 2. Voluntarily repeating the commentary This method allowed the paticipants to voluntarily repeat the commentary at intervals they themselves felt suitable to remind them of the impending danger signal ahead. 9

Investigating the different methods of using RTC MethodAdvantageDisadvantage Voluntary RTC Requires fewer cognitive resources Likely forget the information due to the lower frequency of using RTC Repeating RTC Unlikely to forget the information Increased workload Cause semantic satiation 10 Table 1. The hypothesized advantages and disadvantages of the two different methods of using RTC. Which method is more effective at preventing SPADs?

Investigating the situations that benefit most from using P & C In this research, the use of P & C was investigated in two situations. 1. Single signal situation There was only one signals in the driver’s view. 2. Multi-signal situation There were more than two signals in the driver’s view. It is thought that P & C has an effect of preventing drivers misreading signals (Shigemori et al., 2013). 11 Hypothesis Participants would prefer the use of P & C in multi-signal situations as pointing at the signal would reduce the likelihood of error.

Experiment 12

P & C Stage (Multi-signal) With P & C V.S. Without P & C P & C Stage (Single-signal) With P & C V.S. Without P & C Method Participants Nine train drivers from two railway companies in GB participated in this experiment. All participants were male with an average age of 49. The design of this experiment 13 RTC Stage Repeating RTC V.S. Voluntary RTC P & C Stage (Multi-signal) With P & C V.S. Without P & C P & C Stage (Single-signal) With P & C V.S. Without P & C After each trial in the simulator, the participants completed a questionnaire about their use of RTC and P&C in that trial.

Route- RTC 14 train Platform

Route P & C 15 Single signal route Multi signal route Yellow Signal Green Signal Green Signals

Questionnaire items about RTC No.TitleQuestion 1Confidence How confident were you that you wouldn’t forget the presence of the red signal while driving? 2Difficulty How difficult was it to use RTC? 3 Reduce meaning At any time did you feel repeating the commentary removed the meaningfulness of what you were saying? 4Boredom How bored did you feel while driving? 5Prevent SPADs How effective do you feel using RTC in this way is to prevent SPADs? 16 The five question items from 1 to 5 were answered on using a 7-point Likert scale. Table2. The questions asked after each trial drive in the simulator on RTC routes.

Question items about P & C No.TitleQuestion item 1Confidence How confident were you that you wouldn’t misread the signal aspect while driving? 2Boredom How bored did you feel while driving? 17 Table 3. The questions asked after each trial drive in the simulator on P&C routes. The above two question items were 7-point Likert scale.

Results 18

RTC 19 It can be concluded from these results that participants found the voluntary repetition of the RTC more effective than continuously repeating RTC. It can be concluded from these results that participants found the voluntary repetition of the RTC more effective than continuously repeating RTC. Figure 1. The evaluation to RTC in each question items.

P & C - Confidence - 20 Figure 2. Average participant’s feeling of how confident they were that they would not misread the signal aspect.

P & C - boredom - 21 Figure 3. Average participant’s feeling of boredom.

Discussion 22

RTC The results indicated that participants preferred to use RTC when given the option to use the voluntary repetition method. Workload and difficulty of using constantly repeating RTC was higher than the voluntary repeating RTC. The participants felt the meaningfulness of the commentary was stronger when voluntarily repeating it. The degree of boredom experienced by participants was higher in the constantly repeating RTC condition. 23 The participant‘s perceptions of the effect of RTC on preventing SPADs was larger in the voluntary repeating RTC condition

P & C In this experiment, the effect of P & C was not confirmed despite other studies finding this effect. Why ? Participants were not used to using P & C. The distance of route in this experiment was too short. The number of participants was too few. But the reason for this effect not emerging is unclear. Further research is needed to improve the reliability and validity of these results and to clear the effect of P & C 24

Thank you for your attention. 25