Artificial Intelligence-Based Sentiment Analysis of Dynamic Message Signs that Report Fatality Numbers Using Connected Vehicle Data

This study presents results from sentiment analysis of Dynamic message sign (DMS) message content, focusing on messages that include numbers of road fatalities. As a traffic management tool, DMS plays a role in influencing driver behavior and assisting transportation agencies in achieving safe and efficient traffic movement. However, the psychological and behavioral effects of displaying fatality numbers on DMS remain poorly understood;hence, it is important to know the potential impacts of displaying such messages. The Iowa Department of Transportation displays the number of fatalities on a first screen, followed by a supplemental message hoping to promote safe driving;an example is “19 TRAFFIC DEATHS THIS YEAR IF YOU HAVE A SUPER BOWL DON’T DRIVE HIGH.” We employ natural language processing to decode the sentiment and undertone of the supplementary message and investigate how they influence driving speeds. According to the results of a mixed effect model, drivers reduced speeds marginally upon encountering DMS fatality text with a positive sentiment with a neutral undertone. This category had the largest associated amount of speed reduction, while messages with negative sentiment with a negative undertone had the second largest amount of speed reduction, greater than other combinations, including positive sentiment with a positive undertone.

The Use of Dynamic Message Signs (DMSs) on the Freeways: An Empirical Analysis of DMSs Logs and Survey Data

This study evaluates the Dynamic Message Signs (DMSs) use to dissipate incident information on the freeways in Las Vegas, Nevada. It focuses on the DMSs message timing, extent, and content, from the operators’ and drivers’ perspectives, considering the variability in drivers’ freeway experience. Two-week incidents data with fifty-nine incidents, DMS log data, and responses from a survey questionnaire were used. The descriptive analysis of the incidents revealed that about 54% of the incidents had their information posted on the DMSs;however, information of only 18.6% of the incidents was posted on time. The posted information covered the incident type (54.2%), location (49.2%), and lane blockage (45.8%), while the expected delay or the time the incident has lasted are rarely posted. Further, the standard DMSs are the most preferred sources of traffic information on the freeway compared to the travel time only DMSs, and the graphical map boards. The logistic regression applied to the survey responses revealed that regular freeway users are less likely to take an alternative route when they run into congestion, given no other information is available. Conversely, when given accurate information through DMSs, regular freeway users are about 2.9 times more likely to detour. Furthermore, regular freeway users perceive that the DMSs show clear information about the incident location. Upon improving the DMSs usage, 73% of respondents suggested that the information be provided earlier, and 54% requested improvements on congestion duration and length information. These findings can be used by the DMSs operators in Nevada and worldwide to improve freeway operations.

Paper the Resilience of ITS: Variable Message Signs Contribution to Road Network Resilience under Incident and High Congestion Conditions: A State of the Art Review

Any failure or disruption in traffic flow can propagate through the road network. However, the server of such disruption and its consequences depends on the robustness and resiliency of transportation systems. In this context, traffic management (TM) measures will help the traffic stream to prevent the occurrence of such conditions or recover faster after experiencing the disruption. The main objective of this paper was to elaborate the contribution of TM measures to the resiliency of transportation systems, as well as, their vulnerability against external threats. Furthermore, a concept design for variable message signs (VMS) is developed and evaluated in terms of contribution to the resiliency of road networks. As well, new vulnerabilities associated with the implementation of VMS are investigated. The result of this study pointed out that ramp-metering, variable message signs, variable speed limits, and autonomous vehicles are valuable tools to mitigate the severity of traffic disruptions. VMS is one of the most effective approaches that enhance traffic resiliency by reducing traffic inflow to congested areas. However, these measures have opened new vulnerabilities to threats, especially cyber-attacks. Several cases of VMS hacks have occurred in the world and provided false messages to road users. It gets even worse with using an integrated wireless communication interface. Therefore, it is necessary to consider the security of such systems in advance, before practical application.

Placement Design of Changeable Message Signs on Curved Roadways

This paper presented a fundamental framework for Changeable Message Sign(CMS)placement design along roadways with horizontal curves.This analytical framework determines the available distance for motorists to read and react to CMS messages based on CMS character height,driver's cone of vision,CMS pixel's cone of legibility,roadway horizontal curve radius,and CMS lateral and vertical placement.Sample design charts were developed to illustrate how the analytical framework may facilitate CMS placement design.

Leave the expressway or not? Impact of dynamic information

This study investigates drivers＇ diversion decision behavior under expressway variable message signs that provide travel time of both an expressway route and a local street route. Both a conventional cross-sectional logit model and a mixed logit model are developed to model drivers＇ response to travel time information. It is based on the data collected from a stated preference survey in Shanghai, China. The mixed logit model captures the heterogeneity in the value of ＂travel time＂ and ＂number of traffic lights＂ and accounts for correlations among repeated choices of the same respondent. Results show that travel time saving and driving experience serve as positive factors, while the number of traffic lights on the arterial road, expressway use frequency, being a middle-aged driver, and being a driver of an employer-provided car serve as negative factors in diversion. The mixed logit model obviously outperforms the cross-sectional model in dealing with repeated choices and capturing heterogeneity regarding the goodness-of-fit criterion. The significance of standard deviations of random coefficients for travel time and number of traffic lights evidences the existence of hetero- geneity in the driver population. The findings of this study have implications for future efforts in driver behaviormodeling and advanced traveler information system assessment.

Review of the Effectiveness of Vehicle Activated Signs

This paper reviews the effectiveness of vehicle activated signs. Vehicle activated signs are being reportedly used in recent years to display dynamic information to road users on an individual basis in order to give a warning or inform about a specific event. Vehicle activated signs are triggered individually by vehicles when a certain criteria is met. An example of such criteria is to trigger a speed limit sign when the driver exceeds a pre-set threshold speed. The preset threshold is usually set to a constant value which is often equal, or relative, to the speed limit on a particular road segment. This review examines in detail the basis for the configuration of the existing sign types in previous studies and explores the relation between the configuration of the sign and their impact on driver behavior and sign efficiency. Most of previous studies show that these signs have significant impact on driver behavior, traffic safety and traffic efficincy. In most cases the signs deployed have yielded reductions in mean speeds, in speed variation and in longer head-ways. However most experiments reported within the area were performed with the signs set to a certain static configuration within applicable conditions. Since some of the aforementioned factors are dynamic in nature, it is felt that the configurations of these signs were thus not carefully considered by previous researchers and there is no clear statement in the previous studies describing the relationship between the trigger value and its consequences under different conditions. Bearing in mind that different designs of vehicle activated signs can give a different impact under certain conditions of road, traffic and weather conditions the current work suggests that variable speed thresholds should be considered instead.

Technology acceptance comparison between on-road dynamic message sign and on-board human machine interface for connected vehicle-based variable speed limit in fog area

Purpose–Connected vehicle-based variable speed limit(CV-VSL)systems in fog area use multi-source detection data to indicate drivers to make uniform change in speed when low visibility conditions suddenly occur.The purpose of the speed limit is to make the driver’s driving behavior more consistent,so as to improve traffic safety and relieve traffic congestion.The on-road dynamic message sign(DMS)and on-board human–machine interface(HMI)are two types of warning technologies for CV-VSL systems.This study aims to analyze drivers’acceptance of the two types of warning technologies in fog area and its influencing factors.Design/methodology/approach–This study developed DMS and on-board HMI for the CV-VSL system in fog area on a driving simulator.The DMS and on-board HMI provided the driver with weather and speed limit information.In all,38 participants participated in the experiment and completed questionnaires on drivers’basic information,perceived usefulness and ease of use of the CV-VSL systems.Technology acceptance model(TAM)was developed to evaluate the drivers’acceptance of CV-VSL systems.A variance analysis method was used to study the influencing factors of drivers’acceptance including drivers’characteristics,technology types and fog density.Findings–The results showed that drivers’acceptance of on-road DMS was significantly higher than that of on-board HMI.The fog density had no significant effect on drivers’acceptance of on-road DMS or on-board HMI.Drivers’gender,age,driving year and driving personality were associated with the acceptance of the two CV-VSL technologies differently.This study is beneficial to the functional improvement of on-road DMS,on-board HMI and their market prospects.Originality/value–Previous studies have been conducted to evaluate the effectiveness of CV-VSL systems.However,there were rare studies focused on the drivers’attitude toward using which was also called as acceptance of the CV-VSL systems.Therefore,this research calculated the drivers’acceptance of two normally used CV-VSL systems including on-road DMS and on-board HMI using TAM.Furthermore,variance analysis was conducted to explore whether the factors such as drivers’characteristics(gender,age,driving year and driving personality),technology types and fog density affected the drivers’acceptance of the CV-VSL systems.

The verbiage in variable message signs and traffic diversion during crash incidents

Purpose–WIth limited research on the effects of variable message sign(VMS)message content and verbiage on revealed driver behavior,this study aims to investigate how different verbiage of crash-related messages are related to the diversion rate.Design/methodology/approach–Using ordered logit models,the associations of message verbiage with diversion rates during crash incidents were assessed using five years of VMS message history within a section of I-15 in the state of Utah.Findings–A significant impact of message verbiage on the diversion rate was observed.Based on the analysis results,the crash message verbiage with the highest diversion was found to be miles to crash 1“prepare to stop,”followed by crash location 1 delay information,miles to crash 1“use caution”1 lane of the crash,etc.In addition,the diversion rate was found to be correlated to some roadway characteristics(e.g.occupancy in mainline,weather condition and light condition)along with the temporal variations.Research limitations/implications–These findings could be used by transportation agencies(e.g.state department of transportation[DOTs])to make informed decisions about choosing the message verbiage during future crash incidents.This study also revealed that higher diversion rates are associated with a shorter distance between the crash location and VMS device location,recommending increasing the number of VMS devices,particularly in crash-prone areas.

Evaluation of fog warning system on driving under heavy fog condition based on driving simulator

Purpose–Heavy fog results in low visibility,which increases the probability and severity of traffic crashes,and fog warning system is conducive to the reduction of crashes by conveying warning messages to drivers.This paper aims at exploring the effects of dynamic message sign(DMS)of fog warning system on driver performance.Design/methodology/approach–First,a testing platform was established based on driving simulator and driver performance data under DMS were collected.The experiment route was consisted of three different zones(i.e.warning zone,transition zone and heavy fog zone),and mean speed,mean acceleration,mean jerk in the whole zone,ending speed in the warning zone and transition zone,maximum deceleration rate and mean speed reduction proportion in the transition zone and heavy fog zone were selected.Next,the one-way analysis of variance was applied to test the significant difference between the metrics.Besides,drivers’subjective perception was also considered.Findings–The results indicated that DMS is beneficial to reduce speed before drivers enter the heavy fog zone.Besides,when drivers enter a heavy fog zone,DMS can reduce the tension of drivers and make drivers operate more smoothly.Originality/value–This paper provides a comprehensive approach for evaluating the effectiveness of the warning system in adverse conditions based on the driving simulation test platform.The method can be extended to the evaluation of vehicle-to-infrastructure technology in other special scenarios.

Safety effects of work zone advisory systems under the intelligent connected vehicle environment:a microsimulation approach

Purpose–This study aims to investigate the safety effects of work zone advisory systems.The traditional system includes a dynamic message sign(DMS),whereas the advanced system includes an in-vehicle work zone warning application under the connected vehicle(CV)environment.Design/methodology/approach–A comparative analysis was conducted based on the microsimulation experiments.Findings–The results indicate that the CV-based warning system outperforms the DMS.From this study,the optimal distances of placing a DMS varies according to different traffic conditions.Nevertheless,negative influence of excessive distance DMS placed from the work zone would be more obvious when there is heavier traffic volume.Thus,it is recommended that the optimal distance DMS placed from the work zone should be shortened if there is a traffic congestion.It was also revealed that higher market penetration rate of CVs will lead to safer network under good traffic conditions.Research limitations/implications–Because this study used only microsimulation,the results do not reflect the real-world drivers’reactions to DMS and CV warning messages.A series of driving simulator experiments need to be conducted to capture the real driving behaviors so as to investigate the unresolved-related issues.Human machine interface needs be used to simulate the process of in-vehicle warning information delivery.The validation of the simulation model was not conducted because of the data limitation.Practical implications–It suggests for the optimal DMS placement for improving the overall efficiency and safety under the CV environment.Originality/value–A traffic network evaluation method considering both efficiency and safety is proposed by applying traffic simulation.