Michael E. Rakauskas

Identification of differences between rural and urban safety cultures

The prevailing risk of traffic fatalities is much larger in rural areas compared to urban areas. A number of explanations have been offered to explain this including road design, emergency medical service proximity, and human factors. This research explored the potential contribution of rural driver attitudes that may underlie the increased fatal crash risk in rural environments. This analysis examined differences between rural and urban drivers in terms of self-reported risk taking for driving behaviors associated with fatal crashes and attitudes toward safety interventions using a large-scale survey. The results suggested that rural drivers engage in riskier behavior, such as not wearing seatbelts, because they have lower perceptions of the risks associated with such behaviors. Results also suggested that vehicle type (e.g., pickup trucks versus passenger vehicles) may be related to seatbelt compliance and frequency of driving under the influence of alcohol. Rural drivers perceived the utility of government-sponsored traffic safety interventions to be lower than their urban counterparts. This study provides insights into the role of the human factor in rural fatal crashes and provides policy suggestions for developing safety interventions that are designed with respect to the psychosocial factors that define the rural culture.

Effects of alcohol impairment on motorcycle riding skills

Alcohol intoxication is a significant risk factor for fatal traffic crashes; however, there is sparse research on the impairing effects of alcohol on skills involved in motorcycle control. Twenty-four male motorcycle riders between the ages of 21 and 50 were assessed on a test track with task scenarios based on the Motorcycle Safety Foundations (MSF) training program. A balanced incomplete block design was used to remove confounding artifacts (learning effects) by randomizing four BAC levels across three test days. In general, intoxicated riders demonstrated longer response times and adopted larger tolerances leading to more task performance errors. Most of the alcohol effects were evident at the per se 0.08% alcohol level, but some of the effects were observed at the lower 0.05% alcohol level. The effects of alcohol on motorcycle control and rider behavior were modest and occurred when task demand was high (offset weave), time pressure was high (hazard avoidance for near obstacles), and tolerances were constrained (circuit track). The modest effects may be due to the study design, in which experienced riders performed highly practiced, low-speed tasks; alcohol at these levels may produce larger effects with less experienced riders in more challenging situations.

Differences in Remote versus in-Person Communications While Performing a Driving Task

In Experiment 1, 29 participants performed a simulated driving task both alone and while talking with another participant. Half of the non-driving participants could see the driving scene (in-person communication group) and half could not (remote communication group). When participants performed the driving task while talking with a partner, their situation awareness was significantly less than when they performed only the driving task. Thus, concurrent verbal interactions degraded situation awareness for the driving task. However, the amount of degradation in situation awareness during in-person and remote interactions did not differ significantly. The pace of the in-person and remote verbal interactions differed, suggesting that remote verbal interactions may be more difficult for drivers. Also, drivers talking with remote partners generated more long pauses than drivers talking with in-person partners, suggesting that drivers engaged in remote verbal interactions were modulating their verbalizations in order to maintain adequate driving performance. Experiment 2 replicated the finding that both in-person and remote verbal interactions degraded driving situation awareness, with no significant difference in the amount of degradation for the two types of verbal interaction.

Behavioral Effects of Driver Distraction and Alcohol Impairment

There remains some debate regarding secondary task distractions, such as cell phones, as a risk factor in traffic crashes and their relative risk compared to existing factors, such as engagement in common in-vehicle tasks and alcohol impairment. Moreover, studies of driver impairment often investigate single risk factors rather than combined factors (e.g. distraction task while drunk). This study compared non-distracted driving in a motion-based driving simulator to distracted driving (hands-free cell phone conversations, common in-vehicle tasks) either while sober or combined with alcohol (BAC 0.08). The results indicated that during a car following scenario, drivers engaged in the conversations or completing in-vehicle tasks were more impaired than drivers that were not involved in any distraction task. Indeed, both the cell phone and in-vehicle sources of distraction were generally more impairing than intoxication at the legal limit.

A Binary Response Method to Determine the Usability of Seven In-Vehicle Fuel Economy Displays

We employed a binary response method to evaluate the usability of seven fuel economy displays. The displays were set to show various levels of fuel economy and then static images of the displays were generated. Participants were presented the images and asked to indicate if the information on the fuel economy display indicated fuel economy was greater or less than an arbitrary average fuel economy. A display that consisted of a binary metric of fuel economy and an incremental metric of acceleration best facilitated the determination of fuel economy.

Determining the Accuracy and Acceptance of Using Driver Interface Display Components and Fuel Economy Information Types

If novel displays in the vehicle are not easily understood, they may increase driver distraction and result in higher crash risk. In this way, improving the usability of in-vehicle displays may decrease crash risk. However when there are a large number of interface design options, it is difficult to quickly determine which will be the most beneficial. The goal of this evaluation was to identify fuel economy display components and information types that would have the highest potential to improve accuracy and acceptance. Participants were more accurate at identifying fuel economy level when viewing information presented on horizontal bar display components with reference points. Subjective scores suggested that a balance of instantaneous and long-term information types was associated with greater interface acceptance. Results of this rapid assessment show the utility of supplementing objective accuracy measures with subjective acceptance metrics when considering multiple user interface designs.

Use of a driving simulator to assess performance under adverse weather conditions in adults with albinism

Participants with albinism have reduced vision and nystagmus with reduced foveation times. This prospective study evaluated driving in 12 participants with albinism and 12 matched controls. Participants drove a vehicle simulator through a virtual rural course in sunny and foggy conditions. Under sunny conditions, participants with albinism showed a narrower preferred minimum safety boundary during car-following tasks than did controls, but there was no difference under foggy conditions. Their driving did not differ significantly from that of controls when approaching a stop sign or when choosing gap size between oncoming vehicles when crossing an intersection. However, when compared to control drivers, participants with albinism had a decreased minimum safety boundary for car-following that should be included in counseling regarding driving safety.

A Comparison of Work Domain and Task Analysis for Identifying Information Requirements: A Case Study of Rural Intersection Decision Support Systems

Minnesota drivers are over-represented in accidents at rural intersections and many crashes are attributable to drivers accepting unsafe gaps. In this context, intersection decision support (IDS) systems are promising technologies for supporting driver decision-making. A significant activity during IDS development is to determine the information requirements to display to drivers. To be effective, an IDS system must present information that helps drivers successfully negotiate intersections. This paper compares two methods for identifying information requirements: work domain analysis (WDA) and hierarchical task analysis (HTA). Results showed that 58% of the requirements were identified by WDA, 7% by HTA, and 35% by both methods. An analysis of driver errors at intersections during the HTA activity identified that drivers can perceive gaps at intersections in different ways. This important nuance was not captured in the WDA. Therefore, both WDA and HTA are effective methods for identifying information requirements. Discussion focuses on the importance of both WDA and HTA in IDS system development.

Determining effective orientation and location of decision support signs at rural intersections

Drivers face an increased crash risk when making gap acceptance decisions at high speed, unsignalized, rural intersections. The use of Stop-Sign Assist (SSA) intersection decision-support systems aims to assist drivers with these difficult decisions. This effort to identify effective placement of SSA systems will play a critical role in how the information is interpreted and utilized to successfully navigate an intersection. A driving simulator was used to present virtual representations of an intersection in Minnesota where SSA signs are planned for deployment. This study suggested which angles and locations would result in faster and more accurate comprehension of the signs. These results provide guidance for more effective comprehension, viewing, and acceptance of IDS signs at similar rural, trunk highway intersections.

Rural Stop-Controlled Intersection Decision Support Systems

Minnesota drivers are over-represented in accidents at rural stop-controlled intersections. There is also evidence that drivers in other states as well as older drivers are involved in many of these crashes. A task analysis and literature review showed that rural drivers could be getting into accidents because of problems detecting vehicles or gaps, perceiving or estimating the size of gaps, and/or judging gaps as safe. It is suggested that intersection decision support (IDS) systems present drivers with information elements that help them correctly identify and locate other vehicles and in some cases highlight (safe) gaps in approaching traffic. Several design concepts are proposed and research needs are discussed.