Anja Katharina Huemer

Alcohol-related impairment in the Lane Change Task

The Lane Change Task was developed to provide an objective safety criterion for the assessment of driver distraction by in-vehicle information systems (IVIS). It consists of two basic driving tasks, namely lane keeping and lane changes. The LCT has been shown to reliably detect distraction from driving. As this test becomes increasingly important for the assessment of safety the validity of the LCT is crucial. In order to examine this further, the effect of an alcohol intoxication of 0.08 g/dl on the performance in the LCT was examined in the present study as the negative effects of alcohol on driving are well known. Twenty-three participants were tested under alcohol and placebo in a cross-over design measuring different performance indicators in the LCT. There were significant effects of alcohol during the lane keeping phase. However, these were much smaller than those typically found with distracting secondary tasks. The lane change phase was only marginally affected by alcohol. This result gives rise to some caution for interpreting effects in the LCT. The LCT is well able to detect distraction, as other studies have shown. However, our study with intoxicated participants shows that a small effect in the LCT does not necessarily mean that this condition does not impair driving.

Do German drivers use their smartphones safely?-Not really!

Research in the laboratory as well as in naturalistic driving studies has shown that texting while driving seems to be the most dangerous driver distraction. However, there is still some discussion about the extent to which drivers adapt their behavior to the traffic situation. Accordingly, they might use their phones only in easy driving situations but refrain from doing so when driving becomes more demanding. For Germany, no reliable data on these topics could be found although overall smartphone use has also increased exponentially in this country. As observational studies have proven to be an effective means to gather these data, such a study was done observing 11,837 drivers in three big German cities (Braunschweig, Hannover, Berlin) during daytime. An alarmingly high rate of texting while driving was found (4.5%) as compared to other international studies. This was even more frequent than the use of handheld (2.2%) and hands-free (1.7%) phones combined. Thus, there seems to be a special problem in Germany with texting which should be further examined as this activity is highly distracting. Finally, there was some indication that drivers adapt their secondary task activities to the requirements of the driving task (e.g. somewhat less texting when moving than when stationary at a red traffic light). However, these adaptations were not very strong. Thus, drivers seem to underestimate the dangers due to distraction. This could be a starting point for countermeasures which increase this awareness of danger.

Learning the Lane Change Task: Comparing different training regimes in semi-paced and continuous secondary tasks

For road safety it is paramount that distraction by in-vehicle systems is limited. To reach this aim the Lane Change Task (LCT; Mattes, 2003) was developed. It is used as a test procedure to measure distraction due to secondary tasks in driving. The LCT is implemented as an ISO standard (ISO 26022: 2010) with the aim to provide an objective criterion for designing human-machine interactions (HMI) in a way which is not detrimental to driving. As different baseline performance in the LCT could not be sufficiently explained in recent studies, comparisons of different training regimes were conducted in order to examine training influences on LCT performance. Discriminable performance improvements in LCT were found depending on the secondary task used. A training regime of at least ten runs of LCT in single-task mode is recommended for effective training. This training should be supplemented by a training of the secondary tasks examined. An additional exploration of a dual-task situation is recommended.

Systematic review of observational studies on secondary task engagement while driving

The last decade has seen a worldwide exponential increase in the use of mobile information systems, especially smartphones. This trend covers all areas of life, and also seems to include phone use while driving. In order to assess the scope of secondary task occupation, especially smartphone use while driving, observation studies from outside the car have been established as an efficient and valid method. A review of international studies using traffic observation was done finding 51 publications with a total of 117 observation studies with more than 1,800,000 single observations at more than 17,500 sites from nine different countries. The review describes the relevant aspects of the observation methods and gives an overview about the trends found in the data. As the methods differ widely over the years as well as between the countries and studies, an integration of the results is not possible. However, from all studies it is very clear that smartphone use has increased including not only phoning while driving but also, more important to traffic safety, using apps and texting on the smartphone. Additional observable secondary tasks were only rarely examined. Thus, further research using observational studies is strongly recommended. Suggestions are given with regard to the methodology which can contribute to get comparable and valid results across countries and studies.