Cell Phone

The influence of the use of mobile phones on driver situation awareness

By

Andrew Parkes, Transport Research Laboratory, Crowthorne, England. aparkes@trl.co.uk

&

Victor Hooijmeijer, Verkeersadviesburo Diepens en Okkema, Eindhoven, The Netherlands.

v.hooijmeijer@eindhoven.diepensenokkema.nl

Abstract

The driving performance of 15 subjects in a simulated road environment has been studied both with and

without a hands-free telephone conversation. The performance indicators used were choice reaction time,

braking profile, lateral position, speed, and situation awareness. The driving task was relatively easy, and the

young drivers studies were able to have a hands-free telephone conversation and perform well with respect to

lateral position, the variation in lateral position of the car, and speed maintenance. However, significant

differences were found in choice reaction time, especially in the beginning stages of the telephone conversation,

and in situation awareness. The subjects reacted significantly slower to an unexpected event in the first two

minutes of the telephone conversation and were, for a large part of the telephone conversation, unaware of

traffic movements around them.

Introduction

A survey in the United States has revealed that the vast majority (84%) of mobile phone users believe

that using a phone is a distraction and increases the likelihood of an accident (IRC, 1999). The same

respondents report however that 61% of them use their mobile phone while driving and around 30% use their

phone frequently or fairly often. Since mobile phone use in cars is a relatively new phenomenon, and since the

effects of mobile phone use on traffic safety are still unclear, laws regarding this subject vary between different

countries. Some countries use a mixture of legislation and recommendation, but are not consistent about the

difference in hands-free and hand-held phone use. For example, in Italy only hands-free phones are allowed by

law during driving. At the same time, however, the use of equipment that restricts the hearing senses (which

presumably includes all types of mobile phones) is prohibited. The same situation exists in Spain, whereas in

Portugal, Denmark, and Hungary only hand-held use of mobile phones is prohibited by law (Oei, 1998; United

Nations, 1998). Outside Europe, a hand-held prohibition exists in Israel, Malaysia and some states of the U.S.A.

(Oei, 1998). Germany, France, and Sweden are examples of countries in which no rules or jurisprudence are

used to limit the usage of mobile phones during driving (Becker et al., 1995; Oei, 1998; Petica, 1993).

Nevertheless, it is recommended in Finland and the UK to use hands-free phones only (Oei, 1998). The

situation is confused and changing continually. Only recently, The Netherlands (June 2000)) have jurisprudence

on using handheld mobiles during driving. A driver has been found guilty causing an accident because she was

having a phone conversation. It is likely that many other countries will develop case law in this way even if

legislation does not exist.

At one point, it looked as though the problem for legislators would become easier. Research had

highlighted the potential safety problems with driving and using handheld devices, and it seemed that the

market was leading to the point at which car manufacturers would integrate well-designed handsfree telephones

into their vehicles. Many interested experts claimed that driving and holding a carphone conversation was no

more difficult than talking to passengers, and so, if the handset were removed, the problem would go as well.

Unfortunately the market has gone in a different direction. Personal mobile phones are ubiquitous due to

aggressive and cheap pricing regimes, but handsfree adaptation

kits for use in vehicles, as yet, are not popular. So

the use of handheld devices is actually increasing. Added to this is growing concern that the act of holding a

carphone conversation is fundamentally different to other in-vehicle conversations with passengers (Parkes

1991a and 1991b). So, we are not reducing the number of handsets, and even if we did, it is possible the

problem will remain. This paper reports experimental work focused on an aspect of driving performance that

has not been looked at in-depth in previous studies. In addition to measures of performance such as driver

reaction time and steering ability, we consider higher-order functions that identify not just the ability to control

the vehicle, but also to maintain a clear picture of the traffic situation around the driver during a carphone

conversation.

Method

In the experiment, 15 volunteer subjects were used. The subjects were all (postgraduate) students at a UK

university, aged 22 to 31 (average age = 24.0 years, SD = 2.27 years), with more than 3 years of driving

experience, and little or no experience with using a mobile phone while driving.

A static driving simulator