Investigating an effective method of using risk triggered commentary driving and point and call checks.

Ayanori Sato1), Nicholas Bowler2)

1 Railway Technical Research Institute2 RSSB

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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 2005.

The effects of RTCHelps prevent the user forgetting to do

something (prospective memory error)Helps keep concentration levels raised

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Situations for using RTC No. Situation Purpose

1 On approach to a restrictive signal

Reduce likelihood of a SPAD.

2 On approach to a speed restriction

Reduce likelihood of speeding

3 Checking the route indictor is displaying the correct route

Reduce likelihood of continuing on the wrong route.

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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 & CPreventing misperceptionPreventing action slipKeep concentration level

STOP!

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Situations for using Point and Call checks

Train Drivers check:Traffic SignalTimetableTimeBrake Gauge

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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.

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RTC: the case of SPADsIn some cases, RTC is used for preventing

SPADs

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train

PlatformEvent

• Pass another train• Track maintenance

worker

Driver• Reduce speed• Respond to

AWS• Memorize red

signal

Driver• Reduce

speed• DRA

Forgetting the red signal

EventConversation with passenger

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The Case of using RTC

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train

Plat home

Event• Another train• Track maintenance worker

EventConversation with passenger

Event• Driver does not

accelerate

Driver• Reduce

Speed• Respond to

AWS

train

Driver• Reduce

Speed• DRA

train

Comment

Comment

Comment

train

Comment2

040

Investigating the different methods of using RTCIt 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.

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Investigating the different methods of using RTC

Method Advantage Disadvantage

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

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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 & CIn 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 situationThere 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).

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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

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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

MethodParticipants

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

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RTC Stage

Repeating RTCV.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 & CAfter each trial in the simulator, the participants completed a

questionnaire about their use of RTC and P&C in that trial.

Route- RTC

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train

Platform

Route P & C

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Single signal route

Multi signal route

Yellow SignalGreen Signal Green Signal

Green SignalsGreen Signals Green Signals

Questionnaire items about RTC

No. Title Question

1 ConfidenceHow confident were you that you wouldn’t forget the presence of the red signal while driving?

2 Difficulty 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?

4 Boredom How bored did you feel while driving?

5 Prevent SPADs

How effective do you feel using RTC in this way is to prevent SPADs?

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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. Title Question item

1 Confidence How confident were you that you wouldn’t misread the signal aspect while driving?

2 Boredom How bored did you feel while driving?

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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

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RTC

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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 -

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Figure 2.　 Average participant’s feeling of how confident they were that they would not misread the signal aspect.

P & C - boredom -

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Figure 3.　 Average participant’s feeling of boredom.

Discussion

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RTCThe 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.

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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

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Thank you for your attention.

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