• Journal of Korean Society of Transportation
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• v.27 no.5
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• pp.51-62
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• 2009

Variable message signs (VMS) are a useful tool for providing real-time traffic information to drivers. In particular, effective warning information provision leading to safer driving would be an important countermeasure to prevent traffic accidents. The purpose of this study was to identify users' preferences for traffic safety warning information formats. A variety of warning information scenarios using text and pictograms were devised and investigated for the purpose of selecting more effective methods to provide warning information. A portable variable message sign (PVMS) was used to evaluate users' preferences. The results of this study can be used for designing better warning information for the enhancement of traffic safety.

• Journal of Multimedia Information System
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• v.1 no.2
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• pp.95-100
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• 2014

Variable message signs (VMS) have the different sizes and a specific type according to the city scene and it has to be displayed by different message on the display panel in real-time. And VMS manufacturers must produce the different products in order to give a customized product to each order. In addition that, they should test and check the correct operation to each VMS product using the different message frame. That is very time and workers consuming and VMS emulator with an automatic variable message generator system is necessary. Also, the automatic message generator system is needed to real-time scheduling in order to display the message on the VMS panel like real world. In this paper, we design and implement the VMS emulator embedded the automatic message frame generator system with real-time scheduling which can set several parameters easily on the windows dialog.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.4
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• pp.25-35
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• 2008

Variable Message Sign(VMS) is one of the subsystem of Intelligent Transportation Systems (ITS), which is useful for providing real-time information on weather, traffic and highway conditions. However, there are various situations such as incidents/accidents, constructions, special events, etc., which would be occurred on segments, it is unable to control traffic with only the VMS. Thus, it is essential to use of PVMS(Portable Variable Message Signs), which can move to the location needed traffic control and provide more active traffic information than VMS. This study developed a legibility distance model for PVMS messages using in-vehicle Differential Global Positioning Data(DGPS). Traffic conditions, drivers' characteristics, weather conditions and characteristics of PVMS message were investigated for establishing the legibility model based on multiple linear regression analysis. The factors such as height of PVMS characters, spot speed, age, gender and day and night were identified as dominants affecting the variation of legibility distances. It is expected that the proposed model would play a significant role in designing PVMS messages for providing more effective real-time traffic information.

• The Journal of the Korea Contents Association
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• v.15 no.8
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• pp.69-76
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• 2015

With Various signs are installed at roadside to display the message which rather confuse the drivers. The technologies using advanced lighting system and LED have improved the visibility at nighttime but the problems with plural signs have yet to be resolved. In order to solve this problem, LED and the prismatic variable message sign have been applied. But, they have been provided limited information by the display limit. This research conducted to study patent and technical trend of the existing variable message signs to understand the present technology. And, we suggested next generation display to improve providing information. Therefore, we conducted to compare the LED and the OLED by technical and economical literature review. Also, this research conducted test of luminance contrast about the LED and the OLED display in order to understand the possibility of replacing road signs.

• Wind and Structures
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• v.20 no.6
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• pp.793-810
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• 2015

Tests were conducted at the Florida International University (FIU) Wall of Wind (WOW) to investigate the susceptibility of Variable Message Signs (VMS) to wind induced vibrations due to vortex shedding and galloping instability. Large scale VMS models were tested in turbulence representative of the high frequency end of the spectrum in a simulated suburban atmospheric boundary layer. Data was measured for the $0^{\circ}$ and $45^{\circ}$ horizontal wind approach directions and vertical attack angles ranging from $-4.5^{\circ}$ to $+4.5^{\circ}$. Analysis of the power spectrum of the fluctuating lift indicated that vertical vortex oscillations could be significant for VMS with a large depth ratio attached to a structure with a low natural frequency. Analysis of the galloping test data indicated that VMS with large depth ratios, greater than about 0.5, and low natural frequency could also be subject to galloping instability.

• International Journal of Highway Engineering
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• v.17 no.6
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• pp.97-104
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• 2015

PURPOSES : Expressways experience chronic and recurring congestion, especially during weekends and holidays, because of the increased demands for leisure-related travel. The alternatives to solve chronic and recurring congestion may be three-fold: (1) physical expansion of expressway capacities, (2) road pricing, and (3) temporal and spatial distribution of traffic demands. Among these, the third alternative may be the most cost-effective method for the Korea Expressway Corporation (KEC) that can be achieved by using the existing ITS infrastructure. METHODS : KEC initiated a pilot study in which the traffic on congested expressways was managed by providing traffic condition information (i.e., travel times) of neighboring national highways for taking detours via variable message signs (VMS). This study aimed to estimate the detour rate, and the two pilot studies on Seohaean and Yeongdong expressways yielded many benefits. RESULTS : It was revealed that the total length of congestion segments decreased by 7.8 km, and the average travel speed increased by 5.3 km/h. CONCLUSIONS : Based on these findings, it was concluded that the propagation of detour information via VMSs during congestion hours can help reduce congestion on expressways and increase the benefits of the entire network.

• Proceedings of the KOR-KST Conference
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• 2007.05a
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• pp.383-392
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• 2007

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.4
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• pp.36-48
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• 2008

Variable Message Signs(VMS) is one of the important subsystems of Intelligent Transportation Systems (ITS), which is useful for providing drivers with real-time information on traffic, roadway or weather conditions. In order to maximize the effectiveness of the VMS system, it is required to reflect drivers's preference on designing and operating the system. In this context, this study was conducted to develop strategies to deliver the messages in an efficient manner while many other previous studies focused primarily on the contents of the messages, from drivers's perspectives. Drivers's preference on message expression formats and message display orders were investigated through image analysis in the perspectives of a total of 40 subjects. With respect to message expression formats, drivers preferred Gulim or Dodum in font style, middle arrangement of the letters, pictogram combination as opposed to letters only, blank time less than 0.5 sec, appearing message in animation effect, messages in single phase, non-flashing message. In the matter of message display orders, drivers preferred to obtain link or traffic information in the lust place. Then, they desired to be informed of roadway condition and instructions or recommendations for drivers to cope with unexpected events among various messages for traffic condition.

• Journal of Korean Society of Transportation
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• v.17 no.1
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• pp.91-102
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• 1999

The objective of this study is to evaluate traffic management strategies using Variable Message Signs(MCS) on urban freeways. It is well known that real-time information on traffic conditions increases driver's comfort, and reduces the risks of accidents if drivers are aware of the traffic situation in advance, they decide whether to divert from the freeway or continue on the planned route. The experimental data collected on the Olympic highway we have shown the following results : 1. when the information on both the congested freeway and uncontested diversion route is displayed on the variable message sign. an additional 1.7 percent of traffic diverted, which results in a 3.7 percent reduction in total travel time. 2 Compared with one Proposed VMS message of 'reduce the speed', the other Proposed VMS message of 'keep speed 70km/h' is found to be much more effective in reducing mean speed.

• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.111-120
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• 2007

More accurate vehicle trajectory data are now readily available through Differential Global Positioning Systems (DGPS). A variety of research opportunities emerge with utilization of such high resolution traffic data. A novel approach of this study is to explore drivers' responsive behavior to variable message signs (VMS) by using individual vehicle trajectories extracted from in-vehicle DGPS data. Responsive characteristics of drivers traveling on urban freeways, which can be represented by speeds and acceleration rates, under the provision of real-time traffic information through VMS are statistically investigated. In addition to conducting an ANOVA test, probability density functions of acceleration rates were estimated. The findings of this study can be used to understand the impact of drivers' workload when providing VMS messages on traffic flow patterns. Furthermore, results can be important fundamentals to assist in conducting more realistic traffic simulations.