Graphical Route Information Panel Research Articles

Delay or travel time information? The impact of advanced traveler information systems on drivers’ behavior before freeway work zones

Peak travel times contribute to congestion formation at freeway work zones. Advanced Traveler Information Systems (ATIS) can inform drivers in real-time about the delays and travel times en-route and can provide information about an alternative route to a destination. Different ATIS display strategies are available; however, road authorities lack insights into how time display methods and sign characteristics influence the driving behavior (decelerations, lateral position), the drivers’ attention allocation ability and the subsequent route choice before the freeway diversion. A driving simulator study was conducted with 80 drivers in the State of Qatar to investigate drivers' behavior and voluntary route choices when encountering total travel time (default setting) or delay time updates for two freeway routes on Variable Message Signs (VMS) and Graphical Route Information Panels (GRIP). The GRIPs are a graphical alternative to conventional VMS that can provide drivers with a visual map of the most direct route or an alternative less congested route to a destination using different color schemes. The time difference ratio between the two routes was kept constant to compare the effectiveness of the information designs and investigate the drivers’ attention towards the signs with an eye-tracker. The results showed that the display of zero delays for a detour did influence 74–83% of the drivers to take the alternative route when being displayed on a VMS and a GRIP with free flow attribute framing. When displaying equal total travel times, the GRIP did influence 25% more drivers to follow the alternative route than the VMS. Generally, displaying zero delays for the alternative route resulted in an efficient attention allocation to the first ATIS location and fewer mean decelerations before the repeated ATIS location nearing the diversion. Road authorities are advised to activate the display of delay times to support efficient route choices among freeway drivers.

Dynamic travel information strategies in advance traveler information systems and their effect on route choices along highways

Abstract Advance Traveler Information Systems (ATIS) inform drivers about traffic incidences and expected travel times/ delays en-route. An online computer study was conducted in Qatar to investigate drivers’ willingness to divert to an alternative route given changes in expected travel conditions. Respondents’ route choices were queried after exposure for 6 seconds to varying display strategies. The results from a binary logistic regression and a stated preference survey showed that delay times and displayed colors on a Graphical Route Information Panel (GRIP) effectively influence drivers to take the alternative route, while total travel times were preferred for Variable Message Signs (VMS).

Investigating the Impacts of Graphical Route Information Panel Layouts on Drivers’ Comprehension and Response Time

Graphical route information panels (GRIPs) are an alternative to conventional text-based variable message signs to address different traveler information needs. Since drivers are traveling at higher speeds on the motorways, they have to quickly comprehend and correctly respond to the graphical information displayed on a GRIP. Design elements like the shape of the route map, the meaning of colors indicating congestion and the font sizes of main and minor destinations along the route can influence the comprehension times of drivers. In this study, GRIPs with two purposes (congestion information and event destination information) were presented to 49 Belgian drivers in a computer-based task. All GRIPs were presented on an abstract and naturalistic motorway network shape. Half of the GRIPs were presented with congestion-related colors (red-only or red–orange), and the other half were presented with additional destinations being displayed in different or same font sizes to facilitate drivers visual search on the GRIP. Firstly, travel information statements were presented to the participant, followed by a displayed GRIP layout. Afterward, the participant had to indicate as fast as possible whether the subsequently shown GRIP confirmed the same travel statement. The subjects’ response accuracy and response times were recorded to assess drivers’ quick comprehension of the graphical content. The results of a repeated-measures ANOVA revealed that for GRIP displaying congestion, the red-color element (and not the map shape) significantly reduced drivers response times. A survey among participants also revealed a preference for two-color congestion information, if shown on an abstract map shape. An abstract map shape in combination with different font sizes for major and minor destinations improved drivers’ comprehension and response times to the GRIP, whereas different destination font sizes displayed on a naturalistic map had the contrary effect. The results highlight the importance of graphical design elements with respect to the information purpose.

Why do drivers change route? effect of graphical route information panels

Studies that explore drivers’ decision behaviour under the graphical route information panels (GRIPs) via the discrete choice models have rarely been reported. In this paper, drivers’ route choice response to the GRIPs is quantitatively analysed by using the discrete choice models through a case study of a real-life GRIP in Shanghai, China. A logit model for predicting the route choice probabilities is developed to capture the relationship between the route choice probability, the driver attributes and the GRIP messages, respectively. The modelling results show that the drivers who have a larger annual driving mileage, access the traffic information via the electronic message signs in daily life highly value the GRIPs and drive their car mainly for the commuting purpose are more likely to divert from the original route to the alternate route under the GRIP; a driver's perceived delay of the original route has a positive effect on his diversion decision under the GRIP; there exist differences in the GRIP response behaviour; the drivers are more likely to divert when the GRIP displays ‘red’ to indicate severe congestion on the original route; the female drivers are more sensitive to ‘red’ and more likely to divert.

Comparison of methods of indicating information for designs of graphical route information panels based on expressway users' demand

Comparison of methods of indicating information for designs of graphical route information panels based on expressway users' demand

Developing a Graphical Route Information Panel (GRIP) for use on the UK motorway network. The first steps

This paper describes the initial stages of research to develop design guidelines and draft designs for Graphical Route Information Panels to be used on the UK motorway network to display traffic congestion information. The studies utilised a funnelling approach to initially capture the broad design principles involving all stakeholders and then narrow down the design options using a range of validation and evaluation activities to achieve the desired design guidelines. Guidance for graphical road based display design is presented along with a methodological approach for the implementation of new designs.

A Travel Simulator for Collecting Data on Driver Response to Graphical Route Information Panel

A recent attempt to enhance traveler information services and alleviate congestion is by the use of graphical route information panel (GRIP). This paper proposes a travel simulator for collecting behavioral data on driver response to GRIP. The traffic network conditions and GRIP information are driven by an extended version of the validated high-order continuum model METANET, thus enhancing the realism of the hypothetical travel scenario provided by the simulator. The methodology for simulator design is presented. A prototype simulator was developed.

Study on Drivers’ Comprehension of Advanced Graphical Route Information Panel Considering Individual Attributes

Graphical route information panels (GRIPs) have been commonly used on expressways in Japan to provide drivers with en-route traffic information. Although GRIPs have many advantages over variable message signs (VMSs), too much information and too complex displays may prevent drivers from properly understanding of the provided information. This study proposes advanced GRIPs in which LED displays showing pictograms and moving symbols are installed to assist drivers’ comprehension. The following results were obtained from an online survey conducted to investigate the impact of LED displays: (i) pictograms and moving symbols are helpful to most drivers to correctly understand the event information on GRIPs, but at the same time, they prevent drivers from understanding the travel time information; (ii) in terms of drivers’ comprehension there is a possibility to provide information about natural events (fog and tidal wave) by displaying pictograms or moving symbols on GRIPs.

Why do drivers divert? Impact of graphical route information panels

This study applied a stated preference survey method to investigate the impact of graphical route information panels GRIPs on taxi drivers' diversion decisions. A cross-sectional ordered logit model and a panel data ordered logit model were developed. Main findings are: taxi drivers and mid-age drivers with high urban freeway use frequency are more likely to divert; drivers are more likely to divert if the original ramp is jammed and an accident occurs; employer-provided car drivers are less sensitive to accident and less likely to divert. On the modelling aspect, the panel data model does not provide substantially different model coefficients but more robust statistical inferences; the cross-sectional model tends to seriously overestimate t-test values for explanatory variables changing across drivers and tends to slightly underestimate t-test values for explanatory variables changing across trip scenarios and interaction terms. The findings have implications for GRIP assessment and for future response behaviour modelling effort.

Modeling Traffic Model Driven Route Choice Simulator in UML

A Graphical route information panel (GRIP) benefits transportation induction and alleviating metropolitan congestion. However, facing GRIP, different people give different feedback. The route choice behavior under GRIP derives from many factors. Considering little work paid on the motorists’ route choice behavior under GRIP, in this paper, a traffic model driven route choice simulator is designed in UML. The GRIP module in the simulator is interpreted in detail. A prototype simulator system is also developed in this research.

Drivers’ comprehension of traffic information on graphical route information panels

The concept of using signs to display graphical traffic information is now becoming increasingly popular. The main objective of this study was to design and undertake laboratory research to examine whether the content of traffic information displayed on graphical route information panel (GRIP) could be readily understood. Six kinds of GRIP signs that composed of three changeable information contents (road color only, road color with journey time, and road color with traffic speed) and two different road network types (triangle and tetragon) were proposed and tested in the experiment. Results showed that GRIP with road color only had the greatest optimum route choice percentage and the fastest response time compared to the other contents. On the contrary, GRIP with traffic speed had the slowest response time and the least optimum route choice percentage. Participants took less response time and greater optimum route choice percentage for triangle road network than for tetragon road network. Further, changeable information content interacted with road network type on response time and optimum route choice percentage. The road network type had little effect on response time and optimum route choice percentage under road color only, whereas under road color with journey time and road color with traffic speed, response times increased and optimum route choice percentage decreased significantly as road network complexity increased. Considering drivers’ comprehension and response, using road color only to present traffic condition on GRIP could be an applicable solution. Road color with traffic speed presented on GRIP was not recommended. Road color with journey time can be used for a simple road network. However, it was not suggested for a complex road network. The findings of this study could assist in displaying suitable traffic information on GRIP and in improving efficient driving for motorists.

Graphical route information panel for the urban freeway network in Shanghai, China

The concept of using graphical route information panel (GRIP) to improve the dynamic traffic management efficiency is becoming increasingly popular recently. Colour-coded level-of-service (LOS) map and route travel time are important information displayed by GRIP. This study addresses the graphical information provision issue and the travel time prediction issue, based on research and development of Shanghai urban freeway GRIPs. It first presents function and location of Shanghai GRIP, philosophy of GRIP panel layout and basic principle of LOS display method. Then it focuses on segmentation of LOS map and proposes three segmentation approaches: the detector-based approach, the ramp-based approach and the hybrid approach. Opinions and lessons learned regarding advantages and disadvantages of different segmentation approaches are given. Next, it proposes a macroscopic traffic flow model-based travel time prediction approach for GRIP. The traffic flow model incorporated in the prediction approach is a validated high-order continuum model. The preliminary performance test of the approach is conducted using real-traffic data of a three-lane urban freeway section of Yan-An elevated road in Shanghai. The results reveal that the travel time prediction approach performs well both under free-flowing conditions and under congested conditions. Last, it gives concluding remarks.