Effect of Car Phone usage on Driving Performance

 

Kevin Bogle

Tenth Grade

Classen School of Advanced Studies

 

Oklahoma Junior Academy of Science

Abstract

Many drivers talk on their cellular phones while driving, so it is important to determine if this hurts their ability to drive. The dangers of cell phone use may include reduced competence and difficulty in concentration. Research indicates that people have difficulty simultaneously processing information from more than one source. Can drivers safely listen to the radio and use a car phone? The current study tested driving speed, accuracy, safety, and cognition while driving with and without a car phone. Twenty drivers, 1/3 of whom were regular car phone users, were tested using three driving tasks: serpentine forward and backwards around cones; driving a course with other cars, a figure eight, and a railroad track; and parallel parking. Drivers completed the course twice: once while using a cell phone and once without . The order of conditions was counterbalanced. Two equivalent lists of groceries and directions were used to test cognitive capabilities. The drivers' speed and accuracy were recorded using several measures. A t-test for repeated measures was performed on all measures. Results revealed statistically significant differences with p < .0001, indicating car phone use adversely affected the driving ability of participants when using a car phone. The ability to correctly remember directions and grocery items were also significantly impaired while talking on a car phone. Caution should be used when using a car phone.

"Effect of Car Phone Usage on Driving Performance"

Problem

Many drivers talk on their cellular phones while they are driving. Yet, prior research has not yet determined if this harms their ability to drive their best, and if so to what extent. Cell phones may cause problems with reduced competence and concentration. Ridley (1998) demonstrated that using only one hand to drive may impair performance. Also, Redelmeier & Tibshirani (1997) examined the phone usage logs of 700 drivers who had been involved in traffic accidents. The risk of accident was four times greater for drivers who had used their cellular phones five minutes before their accident occurred. But, whether the drivers were actually on the phone talking when the accidents occurred is not known. According to Redelmeier (1998), car manufacturers may soon put health warnings on their cellular car phones. Coghill (1998) reported that mice developed brain cancer when they were exposed to electromagnetic radiation waves which are emitted from cellular phone waves. These waves supposedly warm the brain tissue of the mice, causing the cancer.

Cognitive psychologists, Solso (1995) and Sternberg (1996), report research that clearly indicates that people have difficulty processing information from more than one source at a time. For example, as early as 1953, Cherry demonstrated that people cannot process information from two auditory inputs simultaneously Neisser & Becklen (1975) showed that people cannot process two visual inputs are the same time. Additionally, Tulving (1989) showed that although some tasks initially require significant attention to the task, they can become somewhat automatic through time and require less cognitive processing. Driving is this kind of process. So the following questions need to be answered: If someone is driving, listening to the radio, and then also talking on the phone how much is their driving ability sacrificed? Are drivers able to concentrate on a task requiring cognitive processing as well when they are driving as when they're not driving?

Although there has been a lot of discussion recently about the use of cellular phones in cars, the accuracy, speed, and safety of drivers both with and without using a cellular phone has not been adequately tested. Last year, research was conducted (Bogle, 1998) using a driving simulator to test driving accuracy, speed, safety, and ability to process information cognitively while driving. The simulated driving situation revealed that all measures of driving were effected severely by the use of the cell phone. The current study was designed to use actual drivers in a realistic driving situation. Would these drivers be able to drive as quickly and efficiently with the cell phone as without it? Would these drivers be able to remember simple driving instructions and a simple grocery list as well with the cell phone as without it ?

Hypotheses

Based on the results of the previous simulation study, the following hypotheses were developed for the current study:

(1) Drivers will remember a grocery list less well when using a cellular phone than when not using a cellular phone.

(2) Drivers will remember directions to a location less well when using a cellular phone than when not using a cellular phone.

(3) Drivers will drive more slowly when using a cellular phone than when not using a cellular phone.

(4) Drivers will make more mistakes and drive more recklessly when using a cellular phone than when not using a cellular phone.

(5) Drivers will parallel park less well when using a cellular phone than when not using a cellular phone.

Participants

Twenty college students from the University of Central Oklahoma volunteered to participate in the study. There were ten females and ten males. Their ages ranged from 16-46; the average age of the drivers was 28 (females-29; males-27). The years of driving experience ranged from 6 months to 30 years; the average number of years of driving was 12 years (females averaged 13 years; males averaged 11 years). One third of both the male and female drivers were regular cellular phone users. The participants were each tested individually for approximately one hour each and then debriefed.

Materials

In order to test how drivers would perform both with and without talking on a cellular phone, it was important to develop realistic driving challenges. The university driving course, used in their driver education program, was adapted. Three driving tasks were developed. First was a Serpentine task, followed by a Driving course, and then a Parallel parking task. All drivers were asked to drive their own vehicles because they would be adequately insured.

Most of the participants indicated that they normally listened to the radio in the car, so they turned in to their normal station. A cellular telephone was placed beside the driver to be used by the participant during one of the two laps around the course.

Two equivalent lists of groceries to be picked up from the grocery store were previously developed. Each list contained eight items. Also two lists of directions were had been previously developed. The directions were equal in difficulty with the same number of elements to be remembered. The list and directions were used in the previous driving simulation experiment.

Other materials included a cellular car phone, a stopwatch, pencils, data sheets, and forms for the drivers to write down the grocery lists and the directions they could recall.

Procedure

First, each student was seated at the steering wheel and tuned in their favorite radio station, if they normally listen to music when they drive. An assistant sat beside the participant in order to give instructions, and the researcher sat in the back seat in order to observe the driving performance and record data. An additional assistant sat inside a nearby building to call the driver on the cell phone at the appropriate time.

The driver was then given a list of eight grocery items and directions to someone's house. Each student repeated each item and each segment of directions after the researcher read them. Next, the participant was given instructions for their first task. After instructions were given, the participants were asked to recall the groceries and the directions. For the first task, the Serpentine task, drivers were asked to drive forward around three cones set in a straight line and stop with the center of the front of the car as close as possible to the last cone. They were then asked to drive backwards around the cones and center the back of their vehicle against the last cone. The number of cones touched, and inches off center from the cones were measured.

The next task was the Driving Course. Drivers were told that both speed and accuracy would be recorded. They drove the course twice which included driving off the road momentarily, around a "cone" car, around a curve, over a hill, around a figure eight, across the highway, over a railroad track, and back to the starting point. The number of weights which tipped over and the number of changes in inertia were counted. In addition, the time it took to complete the course was recorded.

The third task entailed Parallel Parking in a designated parking spot. Whether or not the driver signaled, how centered the vehicle was, and how many inched from the curb they were when they finished were all recorded.

Each driver completed all three tasks both without and with talking on the cell phone. The order of the conditions was counterbalanced. For half of the participants, driving with no phone on was their first condition, followed by talking on the phone next. For the other half, the condition with talking on the phone was first, followed by no phone for their second condition.

During the lap when the cellular phone was used, the phone rang at the beginning of the lap and conversation continued throughout. An assistant gave the participant an equivalent grocery list, and an equivalent set of directions to remember. After the directions were given, the participant was engaged in conversation about their birth, their age, their siblings, their places of residence, their date and location of high school graduation, number of hours finished in college, and courses planned for the upcoming semester. After this course was completed, the participants recalled as many groceries and directions as they could. The amount of time between being given the list and being asked to recall the list was held constant for both lists. The experiment took about an hour for each participant. All of the students were thanked for their participation and the purpose of the experiment was explained.

Results

There were six comparisons made. The number of correctly remembered grocery items and the number of correctly remembered directions were recorded for both conditions: with and without the cellular phone. Next, the mistakes made under the two conditions (with and without cellular phone) were totaled for four measures: 1) Score on the Serpentine task (number of cones hit and inches off center of the cone); 2) Time taken to complete the Driving Course; 3) Score on the Driving Course (number of tumblers fallen plus number on the inertia counter); and 4) Score on the Parallel Parking (whether the driver signaled plus number of inches the vehicle was from the curb. The scores for all four measures, both with and without using the cell phone, were averaged and separate t-tests for correlated measures were performed on all of the data.

For the number of items recalled on the groceries lists, the students averaged 5.5 grocery items without driving and 2.63 number of items recalled while driving. This was a statistically significant difference using a t-test for repeated measures (t (19) = 9.04; p< .00001). For the number of correctly recalled direction items without the phone averaged 6.94 and 2.95 directions recalled with the phone while driving. This was a statistically significant difference using a t-test for repeated measures (t (19) = 11.92; p< .00001).

The students averaged 54.03 on the Serpentine task without talking on the phone and 103.75 on the Serpentine task while talking on the phone (# of cones hit plus # of inches off center). This was a statistically significant difference using a t-test for repeated measures (t (19) = 4.81; p< .0001). The students in this study averaged 3.12 minutes per lap without the phone and 3.51 while talking on the phone. A t-test for repeated measures (t (19) = 6.44; p< .00001) indicated that the lap without the phone took less time; this difference was significant. The students averaged 20.35 on the Driving course score (# of tumblers plus # of counters moved) without the phone and they averaged 31.0 with the phone being used. This was a statistically significant difference using a t-test for repeated measures (t (19) = 4.81; p< .0001). Finally, on the Parallel parking task (signaling + # of inches from curb), the students averaged 22.63 without talking on the phone and 40.35 while talking on the phone. This was a statistically significant difference using a t-test for repeated measures (t (19) = 2.36; p< .0292).

Conclusion

The current study measured the effect of cellular phone use on the speed, accuracy, and performance of drivers. Driving performance was significantly effected. The ability of participants to remember grocery items and directions were both significantly impaired. When driving and talking on a cell phone, tasks which involve mental concentration are hurt. These findings are consistent with the findings of Redelmeier & Tibshirani (1997) who reported cell phone users four times more likely to be involved in an accident. All of the measures used in the current study indicated double or triple the number of errors while driving.

In addition, participants drove significantly worse on all measures when using the cell phone. Participants' speed, accuracy on serpentine and parallel parking tasks, and precision on the driving course was significantly worse when they were talking on the phone than when they were not. Even the speed at which the course was completed was effected. All six measures give the same message: one should not talk on a cell phone and drive if you desire to drive safely.

In summary, because so many drivers are spending time talking on cell phones, it was important to find out how their driving was effected. It was interesting that people who use cell phones regularly thought that they were able to drive just as well, if not better, while on the cell phone as while not on the cell phone. However, their scores reflected just the opposite: their performance, along with everyone else, was significantly worse while on the phone. These people reported that talking on the cell phone helped them concentrate better and stay more focused. They were completely unaware of their errors. This finding is especially important. Not only is driving impaired, and concentration effected, but the drivers are unaware of these impairments. Cellphone use while driving a car is especially dangerous.

 

 

References

"Bad driving under the cellular phone influence." The Internet, address at http://www.btimes.co.za/97/0413/survey6.htm

Burton, L. (1986). Relationship between skills and learning style in problem solving Perceptual and Motor Skills, 62, 48-49.

Redelmeier, Donald A., and Tibshirani, Robert J. (1997). Association between cellular telephone calls and motor vehicle collisions. New England Journal of Medicine, 336, (7), 453-458.

Ridley, K. (1998). British scientists demand warnings for cellular phones. The Internet address at http://www.nando.net.

Solso, R. L. (1998). Cognitive Psychology, Fourth edition. Boston: Allyn and Bacon, pp. 60-94.

Sternberg, R. S. (1996). Cognitive Psychology. Chicago: Houghton-Mifflin, pp. 100-120.



Appendix



Experimental Protocol

Grocery List & Directions

Data Summary Sheet

Statistical Results





Experimental Protocol

The order of conditions for the participants was counterbalanced: for half of the participants their first time through the protocol was without the cell phone and the second time through was with the cell phone; for the other half of the participants they did the first course with the phone on and the second one with the phone off.