Analyzing drivers’ preferences and choices for the content and format of variable message signs (VMS)

Background Recent advance in variable message signs (VMS) technology has made it viable to provide spatio-temporal information on traffic and network conditions to drivers. There is a debate whether VMS diverts drivers’ attention away from the road and may cause unnecessary distraction in their driving tasks due to inconsistent VMS contents and formats. There are also other external factors such as weather conditions, visibility and time of day that may affect the integrity and reliability of the VMS. In China, only about 23% drivers were persuaded by VMS to follow route diversion. Objective In order to capture the full benefits of VMS, the aim of this paper is therefore to identify the factors affecting VMS by examining what kinds of VMS contents, formats and their interactions are more preferable to drivers, specifically in China. Methods A revealed preference (RP) questionnaire and stated preference (SP) survey consisting of 1154 samples from private and taxi drivers was conducted and analyzed using discrete choice model. Results The results revealed that the information showed by amber-on-black on text format, white-on-blue on graph format or the suggested route diversion information showed by single line are preferred by drivers in fog weather. In addition, highly educated drivers or drivers with no occupation are more prone to the qualitative delay time on a text-graph format in fog weather. In normal weather, drivers with working trip purpose are mostly preferred to receive the information on a congested traffic condition with a reason on a text-only format. However, the congested traffic condition along with the information on the apparent causes shown by red-on-black or green-on-black on a text-only format was least preferred by drivers. Regarding current and adjacent road traffic information, drivers prefer to receive the suggested route diversion on a graph-only format in fog weather and the qualitative delay time on a text-graph format in normal weather. Irrespective to weather conditions, male drivers incline to the qualitative delay time on a text-graph format. Conclusions The findings of this study could assist traffic authorities to design the most acceptable VMS for displaying traffic information for the purpose of improving road traffic efficiency and provide the theory evidence for the design of in-vehicle personalized information service system

Observed and expected number of cyclists, pedestrians, motorcyclists, private car drivers, private car passengers, taxi passengers, public bus passengers, and minibus passengers injured in road traffic crashes, Hong Kong, 1998–2017 (dots: observed data; solid lines: expected data; dashed lines: 95% CI).

Observed and expected number of cyclists, pedestrians, motorcyclists, private car drivers, private car passengers, taxi passengers, public bus passengers, and minibus passengers injured in road traffic crashes, Hong Kong, 1998–2017 (dots: observed data; solid lines: expected data; dashed lines: 95% CI).</p

Comparison of fatal injury rate for cycling in Hong Kong with that in other regions worldwide (dots: fatality rate per billion minutes cycled; solid lines: 95% CI; Inclusion criteria: fatalities were defined as those who died immediately at the crash scene or within 30 days of the collision, and cycling time was used as the exposure; data sources: Schneider et al. [25], McAndrews [33], and Bouaoun et al. [34]).

Comparison of fatal injury rate for cycling in Hong Kong with that in other regions worldwide (dots: fatality rate per billion minutes cycled; solid lines: 95% CI; Inclusion criteria: fatalities were defined as those who died immediately at the crash scene or within 30 days of the collision, and cycling time was used as the exposure; data sources: Schneider et al. [25], McAndrews [33], and Bouaoun et al. [34]).</p

A comparison of fatality and injury rates for cyclists on normal weekdays between 2001–2003 and 2010–2012.

A comparison of fatality and injury rates for cyclists on normal weekdays between 2001–2003 and 2010–2012.</p

Fatality and injury rates for cyclists by areas on normal weekdays, Hong Kong, 2010–2012.

Fatality and injury rates for cyclists by areas on normal weekdays, Hong Kong, 2010–2012.</p

Analyzing drivers’ preferences and choices for the content and format of variable message signs (VMS)

Background Recent advance in variable message signs (VMS) technology has made it viable to provide spatio-temporal information on traffic and network conditions to drivers. There is a debate whether VMS diverts drivers’ attention away from the road and may cause unnecessary distraction in their driving tasks due to inconsistent VMS contents and formats. There are also other external factors such as weather conditions, visibility and time of day that may affect the integrity and reliability of the VMS. In China, only about 23% drivers were persuaded by VMS to follow route diversion. Objective In order to capture the full benefits of VMS, the aim of this paper is therefore to identify the factors affecting VMS by examining what kinds of VMS contents, formats and their interactions are more preferable to drivers, specifically in China. Methods A revealed preference (RP) questionnaire and stated preference (SP) survey consisting of 1154 samples from private and taxi drivers was conducted and analyzed using discrete choice model. Results The results revealed that the information showed by amber-on-black on text format, white-on-blue on graph format or the suggested route diversion information showed by single line are preferred by drivers in fog weather. In addition, highly educated drivers or drivers with no occupation are more prone to the qualitative delay time on a text-graph format in fog weather. In normal weather, drivers with working trip purpose are mostly preferred to receive the information on a congested traffic condition with a reason on a text-only format. However, the congested traffic condition along with the information on the apparent causes shown by red-on-black or green-on-black on a text-only format was least preferred by drivers. Regarding current and adjacent road traffic information, drivers prefer to receive the suggested route diversion on a graph-only format in fog weather and the qualitative delay time on a text-graph format in normal weather. Irrespective to weather conditions, male drivers incline to the qualitative delay time on a text-graph format. Conclusions The findings of this study could assist traffic authorities to design the most acceptable VMS for displaying traffic information for the purpose of improving road traffic efficiency and provide the theory evidence for the design of in-vehicle personalized information service system

Fatality and injury rates for cyclists, pedestrians, motorcyclists, private car drivers, private car passengers, taxi passengers, public bus passengers, and minibus passengers on normal weekdays, Hong Kong, 2010–2012.

Fatality and injury rates for cyclists, pedestrians, motorcyclists, private car drivers, private car passengers, taxi passengers, public bus passengers, and minibus passengers on normal weekdays, Hong Kong, 2010–2012.</p

Risk of crash involvement for cyclists, measured by quasi-induced exposure, Hong Kong, 1998–2017 (dots: unadjusted OR; solid lines: 95% CI).

Risk of crash involvement for cyclists, measured by quasi-induced exposure, Hong Kong, 1998–2017 (dots: unadjusted OR; solid lines: 95% CI).</p

Analysis of dynamic determinants of vehicles involved in crash affecting severity based on in-depth crash data

The dynamic characteristics of vehicles involved in crashes may be an important factor affecting the crash severity. This study investigates the relationship between the dynamic characteristics of vehicles involved in crashes in the five seconds before the occurrence and the crash severity. The findings aim to offer insights for preventing severe crashes and advancing autonomous vehicle technology. This study aims to investigate the impact of dynamic features, such as speed, acceleration, and relative distance of vehicles involved in the crash in the five seconds before the crash, on the crash severity. Five hundred ninety-six crash samples from the China In-depth Mobility Safety Study-Traffic Accident database were selected for crash reconstruction. A random parameters logit model was used to extract and analyze the effect of dynamic features of the vehicles involved in the crash on the crash severity. The random parameters logit model demonstrated a satisfactory fit. Analysis of the parameter estimation results of the model showed that the variables of speed, acceleration, and relative distance between vehicles involved in the crash at some time points during the five seconds before the crash significantly affected the crash severity. Notably, the coefficient of variation of relative distance over 5 s emerged as the most influential positive determinant of the crash severity. Certain dynamic characteristics of vehicles involved in a crash in the five seconds before a crash significantly impact the crash severity. The study’s findings can serve as a reference for preventing severe crashes and advancing the development of autonomous vehicles.</p

Road traffic mortality from police data and health data and per capita motor vehicles, China, 1970–2013.

<p>Road traffic mortality from police data and health data and per capita motor vehicles, China, 1970–2013.</p