CELL PHONE USAGE WHILE DRIVING INFLUENCE ON DRIVER'S REACTION TIME

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Frederick Pitts
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1 XII International Symposium "ROAD ACCIDENTS PREVENTION 2014" Hotel Jezero, Borsko Jezero, 09 th and 10 th October UDK: CELL PHONE USAGE WHILE DRIVING INFLUENCE ON DRIVER'S REACTION TIME Igor Milanović a, Željko Ranković b, Aleksandar Gošić c a Ministry of Defense, 1, Kralja Milana St, Vranje, Serbia, igormvr@gmail.com b Ministry of Defense, 15, Nemanjina St, Belgrade, Serbia, zeljko.rankovic@mod.gov.rs c Ministry of Defense, 15, Nemanjina St, Belgrade, Serbia, aleksandar.gosic@mod.gov.rs Abstract: Usage of cell phone without additional equipment during driving, opposite to Road Safety Law in The Republic of Serbia, is very spread, although drivers often are not aware of consequences. Literature review of conducted researches in the world about cell phone harmfulness during driving is presented in the beginning of paper. The research is conducted with 20 drivers by device for measurement of driver reaction time used in medical checkup in The Ministry of Defense. The main goal of the research was to find out how much driver reaction time is increased during usage of cell phone without additional equipment, so how much road way is increased driving by different speed in concrete traffic situations. Keywords: driver reaction, cell phone 1. INTRODUCTION Cell phones are modern devices that we can not imagine today's life without. Beside most positive things that cell phone has, there is a bad habit to use cell phone while driving and, as result, less attention of driver. In every day life and while driving, as well, person gets very huge amount of information from environment by his senses. Most of information are not so important for driver, while one group of them is important. Selection of information has to be done in appropriate way. During usage of cell phone, there are many distractions which additionally disrupt attention of driver. Turning head to cell phone which rings there is visual distraction. Ring of cell phone causes audio distraction by itself. Moving hand to cell phone and holding cell phone are physical distraction, while speaking and attention direction to speaking are cognitive distraction. With development of technique, the number of functions of cell phone is increased. From the first cell phones, which allowed only speaking and chatting, up-to-date cell phones have much more other functions from listening music and internet connection to navigation, that additionally interfere driver s attention. Cell phones are more and more like computers, so computers would not be used while driving. Turning away of attention has direct influence on driver s reaction time, therefore on driver s reaction distance in critical situations. The main goal of the paper is to present how usage of cell phone influences on driver s reaction time. A research was conducted with group of professional drivers in The Ministry of Defense and the Serbian Armed Forces by device for measurement of driver s reaction time and reflexes, while usage of cell phone for speaking.

2 2. RESEARCHES CONDUCTED IN THE WORLD AND SERBIA In the period , web site for selling used cars [1] and The Road Safety Agency conducted anonymous survey with visitors of web site, who expressed their states about usage of cell phones while driving. Opposite to The Road Safety Law in The Republic of Serbia [2] which bans usage of cell phones while driving if there is not equipment for usage of cell phones without hands, even 50% of participants use cell phone in the same way or even more after The Road Safety Law took effect. More than half of participants who paid fine for usage of cell phone while driving constantly do the same. The great number of researches in the world showed that usage of cell phone while driving changes driver s performances, therefore there is higher risk for traffic accident [3], [4], [5], [6]. Even 99% of 1153 professional drivers (or 1036 drivers) who participated in survey in Denmark, use cell phone while driving. 31% of these drivers do not use additional devices or equipment and hold cell phone, even they know that is forbidden. 0.5% of all participants confirmed that they were responsible for traffic accidents caused by usage of cell phone. 6% of all participants confirmed that they caused danger situation in traffic by usage of cell phone. 66% of all participants answered that they were involved in danger situation in traffic caused by usage of cell phone of other traffic participants [7]. Research conducted in USA with 53 participants (32 women and 21 men) had goal to show how content of speaking by cell phone influences on road safety. There were two types of speaking by cell phone while driving: the first speaking about general things from life and the second speaking with emotional strain. It is consolidated that driver who spoke by cell phone with emotional strain made higher number of danger situation while driving [8]. Similar to this research, two researches were conducted in Norway, the first in 1997 with 5007 participants and the second in 2007 with 4307 participants who were involved in traffic accidents. On the basis of those researches, it was concluded that usage of cell phone causes negative changes while driving, which are reasons of more cognitive than physical disruptions. Usage of handsfree devices has high negative influence on driver, as well [9]. Research which was conducted in Taiwan had a goal to show how usage of cell phone influences on driver. There were 12 participants, who were asked by phone while driving in a city and on road out of city. It is confirmed that usage of cell phone influences on driver s ability for driving. Significant increasing of driver reaction time by 11.9% was evidenced in city, opposite to high-road, as long as driving speed while speaking by cell phone decreased by 5.8% [10]. On the basis of 33 conducted studies, Caird and others concluded that cell phones have big influence on driver s ability for driving. The biggest problem which is appeared is increasing of driver s reaction time in different traffic situations. There is not high deviation between driver s reaction time when driver uses cell phone holding by hand or using handsfree. It is noticed that driver s reaction time was increased by 0.25 s for tasks which drivers received while driving. According to these researches, the main problem is underestimation of usage of cell phone while driving, especially its influence on driver s skills [11]. In 2009 a research was conducted in USA where 36 participants crossed street on virtual lane. Firstly, participants crossed street with no usage of cell phone, afterwards they repeated in the same way but speaking and listening to music by cell phone. It was proved that higher influence on pedestrians had speaking by cell phone [12]. The second research, which was conducted with 22 young drivers in 2002 in USA, had the main goal to find out influence of listening to music in car, speaking by cell phone and talking to passengers, on driver s reaction time. It was shown that listening to music did not influence on reaction time, but speaking by cell phone and talking to passengers influenced negatively on reaction time [13].

9% of all drivers do not have handsfree device, while 32% of drivers who have handsfree device, have never used it [14]. 3. METHODOLOGY OF CONDUCTED RESEARCH Driver s reaction time measurement was carried out by reaction time meter.

3 There was conducted a research in Australia, with 796 participants of both genders and various ages. 43% of all participants answer on cell phone call while driving, 36% call while driving, 37% read received messages while driving, and 18% typing messages while driving. 63.9% of all drivers do not have handsfree device, while 32% of drivers who have handsfree device, have never used it [14]. 3. METHODOLOGY OF CONDUCTED RESEARCH Driver s reaction time measurement was carried out by reaction time meter. The device for measurement of complex reaction Multihrono 803 is intended for testing of The Ministry of Defense and The Serbian Armed Forces members complex psychomotor abilities, which manifest while executing different jobs and working tasks, as driver s in this case. In technical view, it comprises central unit which is connected with buttons for hands and pedals for legs. Test includes switching off lamps by pressing appropriate buttons simultaneously. The test comprises 15 different complex tasks. Device is linked to computer by cable and allows data reading in miliseconds from reaction time meter, with the help of measurement list, and statistical analysis in real time. Device records: the name of test, task number, completition time in miliseconds, time of wrong reaction in tasks with marked mistake, summary time of test and number of correct and wrong answers. Figure 1. Work on reaction time meter Multihrono 803 During regular control of drivers in The Ministry of Defense and The Serbian Armed Forces, mean of reaction time must not be higher than s, and driver must not have more than 3 mistakes. Driver who does not satisfy this limitations, has to repeat the same way on additional check ups, and if he does not satisfy it, he will be moved to other duty. This research comprised men drivers, ages from 23 to 40, drive experience from 4 to 21 years. Before research with cell phones, every driver did the same test on reaction time meter with no usage of cell phone. That was done in order to check his reaction time without influence of cell phone, and to find out how usage of cell phone influence on reaction time. Test was carried out in the way that every driver received call before beginning of test. Call was sent from room next to this. Driver got task to answer the call and hold cell phone in the same way as they do it in real situations. Some of them held cell phone on shoulder and held buttons by both hands, while some of drivers held cell phone by hand, and both buttons for hands pushed by one hand.

4 Some questions are asked during speaking, whose topic was ordinary from life, but in the way that driver has to give cognitive effort. Some of answers asked in speaking: What is your ID number? Correct address? How do you commute? Who do you live with? Which car you used to drive? Which petrol do you use and what is your engine power? What size of your shoes is? Who is your superior? etc. While driver answered the questions, device measured reaction time. 4. THE RESULTS OF RESEARCH Statistical analysis of this research was carried out by IBM SPSS Statistics SPSS (Statistical Product and Service Solutions), software intended for this kind of statistical analysis. This sort of tool is consisted of several moduls, used for creating and development of research through polls (IBM SPSS Data Collection), collecting data (IBM SPSS Modeler), text analysis and cooperation and development (series and automatized appraisal). Results of test are given in table 1. N 0 Ages Experie nce ages Table 1. Results of test with no usage of cell phone Number Average reaction of time mistakes while speaking by cell phone Number Average reaction of time mistakes , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,615 4 After data analysis, basic values of summary statistics are given in table 2.

5 Table 2. Basic values of summary statistics Statistics Reaction time with no usage of cell phone Reaction time while speaking by cell phone N Valid Missing 0 0 Mean,46485,69240 Median,47850,69100 Std. Deviation,066829, Minimum,329,493 Maximum,607 1,009 Percentiles 25,41300, ,47850, ,50050,76925 On the basis of data from table, reaction time mean with no usage of cell phone is s, and standard deviation is Reaction time mean whilw speaking by cell phone is s, and standard deviation is The elements of descriptive statistics are given in table 3. Reaction time with no usage of cell phone Reaction time while speaking by cell phone Table 3. Descriptive statistics of collected data Descriptives Statistic Std. Error Mean,46485, % Confidence Interval Lower Bound,43357 for Mean Upper Bound, % Trimmed Mean,46450 Median,47850 Variance,004 Std. Deviation, Minimum,329 Maximum,607 Range,278 Interquartile Range,087 Skewness -,213,512 Kurtosis,255,992 Mean,69240, % Confidence Interval Lower Bound,62639 for Mean Upper Bound, % Trimmed Mean,68589 Median,69100 Variance,020 Std. Deviation, Minimum,493 Maximum 1,009 Range,516 Interquartile Range,180 Skewness,638,512 Kurtosis,260,992

On the basis of data from table, it is concluded that value of Median while speaking by cell phone is increased for 0.213.

means if 5% of lower and upper bound is trimmed (respectively 0.46485/0.46450, 0.69240/0.68589).

There are two the most representative tests: Kolmogorov-Smirnov and Shapiro-Wilk.

05, that means reaction time have normal distribution. Table 4. Tests of Normality Tests of Normality Kolmogorov-Smirnov a Shapiro-Wilk Statistic df Sig.

6 On the basis of data from table, it is concluded that value of Median while speaking by cell phone is increased for Values 5% Trimmed Mean show fact that there is not significant difference between means and these values, in other words there is not difference between means of these two groups of data and means if 5% of lower and upper bound is trimmed (respectively / , / ). Therefore, it is concluded that collected data are concentrated around means, so it can be concluded by low values of standard deviation. Test of Normality values are given in table 4. There are two the most representative tests: Kolmogorov-Smirnov and Shapiro-Wilk. According to the fact that Shapiro-Wilk is common for small samples (<50 participants), values from this test will be taken for analysis. The values in column Sig. are higher than 0.05, that means reaction time have normal distribution. Table 4. Tests of Normality Tests of Normality Kolmogorov-Smirnov a Shapiro-Wilk Statistic df Sig. Statistic df Sig. Reaction time with no,128 20,200 *,971 20,780 usage of cell phone Reaction time while,114 20,200 *,948 20,342 speaking by cell phone a. Lilliefors Significance Correction *. This is a lower bound of the true significance. The histograms of these two groups of data are shown in figures 2 and 3. Figures 2 and 3. The histograms of reaction time with no usage of cell phone and reaction time while speaking by cell phone Figures 4 and 5. Q-Q (Quantile-Quantile) Probability Plot for both groups of data

Graphic interpretations are given in picture 4 and 5. On the basis of these graphs, it can be seen that there is significant composition of observed and expected data.

7 Graphic interpretations are given in picture 4 and 5. On the basis of these graphs, it can be seen that there is significant composition of observed and expected data. Data distribution and comparative view are given in picture 6. From picture, there is reaction time increasing in the second group while speaking by cell phone, but also significant data dispersion according to the first group of data with no usage of cell phone. Figure 6. Data distribution (Box Plots) according to group of reaction time After review of basic data about distribution, first thing is to assess means between groups of reaction time data and using appropriate test to assess null hypothesis: The means of these two groups od reaction time data (taken with no usage of cell phone and taken while speaking by cell phone) are identical. For this purpose, Paired-Samples T test is used. This sort of test is used for comparison of means values of two groups of variables. After analysis, data which are provided are given in table 5. Pair 1 Reaction time with no usage of cell phone - Reaction time while speaking by cell phone Mean -, Table 5. The results of Paired-Samples T test Paired Samples Test Paired Differences Std. Deviation Std. Error Mean,158143, % Confidence Interval of the Difference Lower Upper -, , t df Sig. (2- tailed) -6,435 19,000

8 The data from table manifest that there is strong evidence of significant difference between means of these two groups (t(19)=-6.435, p < ), therefore means are not identical. Due to the fact that comparison of means is carried out, the next thing is to test hypothesis H0: Reaction time is changed and increased while speaking by cell phone. For this purpose, Wilcoxon Signed Ranks Test is used, and 2 Related Samples Test, as well. Values are given in table 6 and 7. Reaction time with no usage of cell phone - Reaction time while speaking by cell phone Table 6. Values of data ranks. Ranks N Mean Rank Sum of Ranks Negative Ranks 0 a,00,00 Positive Ranks 20 b 10,50 210,00 Ties 0 c Total 20 a. Reaction time while speaking by cell phone < Reaction time with no usage of cell phone b. Reaction time while speaking by cell phone > Reaction time with no usage of cell phone c. Reaction time while speaking by cell phone = Reaction time with no usage of cell phone Table 7. Values of test statistics Test Statistics b Reaction time with no usage of cell phone - Reaction time while speaking by cell phone Z -3,920 a Asymp. Sig. (2-tailed),000 a. Based on negative ranks. b. Wilcoxon Signed Ranks Test According to the values Z=-3.92, p<0.005, and Asymp. Sig. (2-tailed)=0.0 it can be concluded that hypothesis is correct and that there is significant statistical difference between reaction time with no usage of cell phone and reaction time while speaking by cell phone. 5. CONCLUSION Large number of papers in the world prove that usage of cell phone while driving without additional equipment has negative influence on driver, therefore has negative influence on raod safety. Conducting of this research tried to confirm how driver reacts slowly when uses cell phone while driving in two ways: first, when driver holds cell phone by a hand and second, when driver put cell phone on his shoulder or he does not use additional equipment while he reacts in different situations. Average longer reaction time is s, which seems to be small, but when velocity is 50 km/h (maximum speed for town or speed limit) car moved more than three meters, when velocity is 80 km/h more than five meters, and when velocity is 120 km/h more than seven meters. It should be noticed that drivers, while testing, could expect signal for reaction, and were ready that thay had to react. In real traffic situation, driver can rarely expect that he has to react in the next ten seconds, but driver concentrate to speaking, holding cell phone and, as result, reaction time is quite longer.

9 The number of mistakes also confirms that drivers did not pay attention to reaction while they were speaking by cell phone, so speaking interfered with attention and there were more mistakes. In real situation, one wrong reaction makes difference between danger situation and traffic accident. It is maybe bigger problem than longer reaction time, due to the fact that drivers with no usage of cell phone made 49 mistakes (or 2.45 per driver), and with usage of cell phone 61 mistake (or 3.05 per driver). This research shows that cell phones have negative influence on drivers, therefore drivers have to be aware that while driving, they have to be concentrated on driving and have to pay attention to situation, because more function of cell phone, beside speaking, interfere with driver s attention more and more. 6. REFERENCES [1] www. polovniautomobili.com [2] Zakon o bezbednosti saobraćaja na putevima (2009). Službeni glasnik RS broj 41/09, Beograd. [3] Nasar, Ј., Hecht, P., Wener, R. (2008). Mobile telephones, distracted attention, and pedestrian safety. Accident Analysis and Prevention, Vol. 40, pp [4] Beede, E.K., Kass, J.K. (2006). Engrossed in conversation: The impact of cell phones on simulated driving performance. Accident Analysis and Prevention, Vol. 38, pp [5] Marie-Pierre Bruyas, P.M., Brusque, C., Debailleux, S., Duraz, M., Aillerie. I. (2009). Does making a conversation asynchronous reduce the negative impact of phone call on driving? Transportation Research Part F, Vol. 12, pp [6] Ishigami, Y., Klein, M.R. (2009). Is a hands-free phone safer than a handheld phone? Journal of Safety Research, Vol. 40, pp [7] Thomas Troglauer, T., Hels. T., Christens, F., Falck, P. (2006). Extent and variations in mobile phone use among drivers of heavy vehicles in Denmark. Accident Analysis and Prevention, Vol. 38 [8] Dula, S.C., Martin, A.B., Fox, T.R., Leonard, L.R. (2011). Differing types of cellular phone conversations and dangerous driving. Accident Analysis and Prevention, Vol. 43, pp [9] Backer-Grøndahl, A., Sagberg, F., (2011). Driving and telephoning: Relative accident risk when using hand-held and hands-free mobile phones. Safety Science, Vol. 49, pp [10] Liu, S.B., Lee, Y.H. (2006). In-vehicle workload assessment: Effects of traffic situations and cellular telephone use. Journal of Safety Research, Vol. 37, pp [11] Caird, K.J., Willness, R.C., Steel, P., Scialfa, C. (2008). A meta-analysis of the effects of cell phones on driver performance. Accident Analysis and Prevention, Vol. 40, pp [12] Neider, B.M., McCarley, S.J., Crowell, A.J., Kaczmarski, H., Kramer, F.A. (2010). Pedestrians, vehicles, and cell phones. Accident Analysis and Prevention, Vol. 42, pp [13] William Consiglio, W., Driscoll, P., Witte, M., Berg, W.P. (2003). Effect of cellular telephone conversations and other potential interference on reaction time in a braking response. Accident Analysis and Prevention, Vol. 35, pp [14] White, M.K., Hyde, M.K., Walsh, P.S., Watson, B. (2010). Mobile phone use while driving: An investigation of the beliefs influencing drivers hands-free and hand-held mobile phone use. Transportation Research Part F, Vol. 13, pp

APPENDIX. Appendix 2. HE Staining Examination Result: Distribution of of BALB/c

APPENDIX. Appendix 2. HE Staining Examination Result: Distribution of of BALB/c APPENDIX Appendix 2. HE Staining Examination Result: Distribution of of BALB/c mice nucleus liver cells changes in percents between control group and intervention groups. Descriptives Groups Statistic