Evaluation of Alternative Messages and Sign Locations on Driver Response to a Dynamic Speed Feedback Sign on a Freeway Interchange Ramp

2020 ◽  
Vol 2674 (12) ◽  
pp. 530-541
Author(s):  
Timothy J. Gates ◽  
Md Shakir Mahmud ◽  
Anthony J. Ingle ◽  
Matthew Motz ◽  
Travis Holpuch ◽  
...  
Keyword(s):  
Driver Behavior ◽  
Field Evaluation ◽  
Speed Reduction ◽  
Driver Response ◽  
Heavy Trucks ◽  
Warning Message ◽  
Feedback Sign ◽  
Speed Management ◽  
Speed Selection ◽  
Advisory Speed

Research was undertaken to determine effective messaging strategies and sign positions for dynamic speed feedback signs (DSFS) when used for speed management at freeway ramp curves. A field evaluation was performed in this setting to assess the impacts of a DSFS on driver speed selection and braking characteristics while approaching and entering the curve. Three feedback messaging strategies were evaluated at three sign positions in advance of the curve. Compared with the existing site (without the DSFS), the DSFS reduced curve entry speeds and improved brake response across all test conditions, particularly for heavy trucks. Overall, considering the combination of both sign position and feedback messaging strategy, the greatest benefits to driver behavior were attained when the DSFS was positioned 255 ft upstream of the curve and the feedback message included the speed number alternating with a SLOW DOWN message. The inclusion of an advisory speed panel with the DSFS did not have a substantive impact on driver behavior. Based on the findings, the continued use of DSFS as a speed reduction treatment at freeway ramp curves is recommended. Specifically, the sign should be positioned to provide adequate time for drivers to perceive and react to the message, such that comfortable braking can be accommodated while approaching the curve. However, the sign should not be placed too far in advance of the curve, as drivers may be more likely to disregard such a premature warning message. Further evaluation of DSFS under various alternative ramp configurations is recommended.

scholarly journals Driver Response to a Dynamic Speed Feedback Sign on Freeway Exit Ramps based on Sign Location, Interchange Type, and Time of Day

2020 ◽  
Author(s):  
Shakir Mahmud ◽  
Matthew Motz ◽  
Travis Holpuch ◽  
Anthony J. Ingle ◽  
Timothy Gates ◽  
...  
Keyword(s):  
Substantial Reduction ◽  
Light Condition ◽  
Field Evaluation ◽  
Time Of Day ◽  
Speed Reduction ◽  
Driver Response ◽  
Horizontal Curves ◽  
Before And After ◽  
Feedback Sign ◽  
Straight Segments

Roadway segments that include horizontal curves experience a disproportionate number of crashes compared to straight segments. Many of these crashes are lane departure-related, and excessive speed is often a contributing factor. One particularly vulnerable area for such crashes is freeway interchange ramps, which require a substantial reduction in speed to be safely negotiated. While dynamic speed feedback signs (DSFS) have been found to be an effective speed and crash reduction countermeasure at horizontal curves, the use of such signs on freeway interchange ramps has been limited nationwide. Consequently, the effectiveness of DSFS as a speed reduction countermeasure in such settings has remained largely untested. A before-and-after field evaluation was performed at three freeway exit ramps to assess the impacts of a DSFS on driver speed selection and braking characteristics while approaching and entering the ramp curves. The effectiveness of the feedback sign was tested across various conditions, including sign location, interchange type, time of day, light condition, and vehicle type. In general, the greatest benefits to driver behavior were achieved with the DSFS positioned at the point of curvature, during which curve entry speeds were reduced by approximately 2 mph compared to the pre-DSFS condition. These findings were consistent between the system- and service-interchanges and across all vehicle types. The DSFS was also found to be most effective during daytime off-peak periods compared to peak periods and at night. Based on the study findings, the continued use of DSFS as a speed reduction treatment at freeway exit ramps is recommended.

scholarly journals Driver Response to a Dynamic Speed Feedback Sign on Freeway Exit Ramps Based on Sign Location, Interchange Type, and Time of Day

2021 ◽  
pp. 036119812110152
Author(s):  
Md Shakir Mahmud ◽  
Matthew Motz ◽  
Travis Holpuch ◽  
Jordan Hankin ◽  
Anthony J. Ingle ◽  
...  
Keyword(s):  
Time Of Day ◽  
Light Conditions ◽  
Driver Response ◽  
Beneficial Effects ◽  
Passenger Vehicles ◽  
System Versus ◽  
Feedback Sign ◽  
Speed Selection ◽  
Peak Versus ◽  
Horizontal Curvature

A series of field evaluations was performed at three freeway interchange ramps in Michigan that possessed significant horizontal curvature to assess the impacts of a dynamic speed feedback sign (DSFS) on driver speed selection and brake response while approaching and entering the ramp curve. A DSFS with a 15 in. full-matrix display was temporarily installed at each of the three exit ramp locations. The sign was programmed to display the same feedback message at each location, which included the speed number for all approaching vehicles, which alternated with a “Slow Down” message for vehicles approaching above 40 mph. The effectiveness of the feedback sign was tested across various sign locations (at the point of curvature versus 350 ft upstream), interchange types (system versus service), time of day (peak versus off-peak), light conditions (daylight versus darkness), and vehicle types (passenger vehicles versus trucks). Compared with the pre-DSFS site condition, the DSFS reduced curve entry speeds and improved brake response at two of the three ramp locations. In general, the greatest beneficial effects on driver behavior were achieved when the DSFS was positioned at the point of curvature, during which curve entry speeds were reduced by approximately 2 mph. These findings were consistent between the system interchanges and service interchanges, and across all vehicle types. The DSFS was also found to be most effective during daytime off-peak periods compared with peak periods and at night. Further evaluation of DSFS at additional ramp locations, and considering an expanded set of conditions, is recommended.

scholarly journals Evaluating Driver Response to a Dynamic Speed Feedback Sign at a Freeway Exit Ramp Considering the Sign Design Characteristics and Lateral Installation Position

2021 ◽  
Author(s):  
Shakir Mahmud ◽  
Babak Safaei
Keyword(s):  
Lateral Position ◽  
Sign Test ◽  
Detection Range ◽  
Speed Reduction ◽  
Driver Response ◽  
Feedback Sign ◽  
Improved Performance ◽  
Design Characteristics ◽  
Horizontal Curvature ◽  
Exit Ramp

Research was conducted at a freeway exit ramp with significant horizontal curvature to evaluate the effectiveness of dynamic speed feedback signs (DSFS) as a speed reduction countermeasure. Several aspects of the DSFS were evaluated, including display size, border type, lateral installation position, and vehicle detection range. Three different full-matrix DSFS were utilized, which included: 15-inch display panel with yellow border, 18-inch display panel with yellow border, and 18-inch display panel with no border. Each sign was individually installed and tested at identical locations near the start of the exit ramp curve, in both the traditional right-side-mount and an alternative forward-mount within the exit gore area. Speed data and message activation location were collected for vehicles approaching and entering into the curve across the various sign test conditions. Overall, the presence of a DSFS positioned near the start of the curve resulted in curve entry speeds that were, on average, 3.5 mph lower than without a DSFS present at the site. The lowest curve entry speeds were observed for cases where the message activated when vehicles were within 250 to 400 ft of the curve. Interestingly, earlier message activation did not contribute to further speed reductions, although later activation substantially diminished the speed reduction effects. Regarding DSFS lateral position, both the side-mounted and forward-mounted DSFS installations resulted in similar curve entry speeds. Furthermore, there were no discernable differences in curve entry speeds between the 15-inch and 18-inch display panels, although the inclusion of a yellow sign border improved performance.

Driver Response Times to Side Road Path Intrusions from SHRP-2 Naturalistic Database

2020 ◽  
Vol 64 (1) ◽  
pp. 1525-1529
Author(s):  
Swaroop Dinakar ◽  
Jeffrey Muttart ◽  
Jeffrey Suway ◽  
J.S. Forensics ◽  
Jim Marr ◽  
...  
Keyword(s):  
Emergency Response ◽  
Response Times ◽  
Driver Behavior ◽  
The Other ◽  
Response Behavior ◽  
Driver Response ◽  
Emergency Events ◽  
Behavior Systems

In an age where all major manufacturers are trying to get a better understanding of when an emergency response should be triggered, it becomes imperative to learn how humans respond to emergency events. If one can understand driver behavior, systems can be designed around the user to either assist drivers where they fail to perform well or completely eliminate them from the accident avoidance maneuver. In this study, 169 crash and near crash events from the SHRP2 dataset were analyzed. The response behavior of drivers was measured in events where the through drivers’ path was intruded upon by another vehicle perpendicular to its path. Overall, drivers responded significantly faster when the other vehicle failed to stop, and at intersection locations.

scholarly journals Speed management as a measure to improve road safety on Polish regional roads

2017 ◽  
Vol 43 (3) ◽  
pp. 29-42 ◽  
Author(s):  
Stanisław Gaca ◽  
Sylwia Pogodzińska
Keyword(s):  
Road Safety ◽  
Speed Limits ◽  
Speed Reduction ◽  
Average Speed ◽  
Traffic Calming ◽  
Management Measures ◽  
Speed Management ◽  
Speed Up ◽  
Road Segments ◽  
Local Speed

The article presents the issue of the implementation of speed management measures on regional roads, whose character requires the use of different solutions than those on national roads. The authors briefly described speed management measures, the conditions for their implementation and their effectiveness with reference to environmental conditions and road safety. The further part of the paper presents selected results of the authors' research into the speed on various road segments equipped with different speed management measures. The estimations were made as to the impact of local speed limits and traffic calming measures on drivers' behaviour in free flow conditions. This research found that the introduction of the local speed limits cause reduction in average speed and 85th percentile speed up to 11.9 km/h (14.4%) and 16.3 km/h (16.8%) respectively. These values are averaged in the tested samples. Speed reduction depends strongly on the value of the limit and local circumstances. Despite speed reduction, the share of drivers who do not comply with speed limits was still high and ranged from 43% in the case of a 70 km/h limit, up to 89% for a 40 km/h limit. As far as comprehensive traffic calming measures are concerned, results show decrease in average speed and 85th percentile speed up to 18.1 km/h and 20.8 km/h respectively. For some road segments, however, the values of average speed and 85th percentile speed increased. It confirms that the effectiveness of speed management measures is strongly determined by local circumstances.

Comparison of Three Traffic Management Plans Showing Shadow and Police Vehicle Effects on Driver Behavior at Highway Single Lane Closures

2020 ◽  
Vol 2674 (9) ◽  
pp. 15-25
Author(s):  
Ross Blackman ◽  
Matthew Legge ◽  
Ashim Kumar Debnath
Keyword(s):  
Traffic Management ◽  
Injury Risk ◽  
Driver Behavior ◽  
Night Time ◽  
Buffer Area ◽  
Driver Response ◽  
Management Plans ◽  
Efficiency And Effectiveness ◽  
Positive Effect ◽  
Lane Closures

Lane closures on multi-lane roads require drivers to transition safely to an open lane before passing the worksite. To reduce worker and driver injury risk, truck-mounted attenuators (TMAs) are often used to prevent vehicle work zone intrusions and reduce the severity of collisions. To maximize the efficiency and effectiveness of TMA use, it is necessary to determine how and when they should be deployed as well as the best supporting measures. The current research focuses on the effects of different traffic management plans (TMPs) on driver behavior. Three TMPs at night time highway work zones were examined: ( 1 ) two tail vehicles in the advance warning area, ( 2 ) three tail vehicles in the advance warning area, and ( 3 ) addition of a marked police car with flashing lights in the buffer area downstream of the TMA. Driver response to the different TMPs was assessed by measuring vehicle speeds at three points in the traffic management area and observing lane change and merging behaviors on the approach to the TMA. Analysis showed a positive effect of police presence in the buffer area on driver behavior: TMP3 produced a reduction of 8.4%–12.9% in proportions of vehicles exceeding the speed limit by at least 5 km/h when passing the TMA. TMP3 also appeared to produce a positive effect on merging behavior compared with the other layouts. Use of a third tail vehicle in the advance warning area was not found to produce any additional safety benefit and may have a detrimental effect.

Vehicle Evaluation of the Performance of Magneto Rheological Dampers for Heavy Truck Suspensions

2001 ◽  
Vol 123 (3) ◽  
pp. 365-375 ◽  
Author(s):  
David Simon ◽  
Mehdi Ahmadian
Keyword(s):  
Control Policy ◽  
Field Evaluation ◽  
Vehicle Body ◽  
Mr Dampers ◽  
Heavy Trucks ◽  
Acceleration Data ◽  
Passive Dampers ◽  
Heavy Truck ◽  
Driving Conditions ◽  
Magneto Rheological

This study is intended to complement many existing analytical studies in the area of semiactive suspensions by providing a field evaluation of semiactive magneto rheological (MR) primary suspensions for heavy trucks. A set of four controllable MR dampers are fabricated and used experimentally to test the effectiveness of a semiactive skyhook suspension on a heavy truck. In order to evaluate the performance of the semiactive suspensions, the performance of the truck equipped with the MR dampers is primarily compared with the performance of the truck equipped with the stock passive dampers. The performance of the semiactive system and the original passive system are compared for two different driving conditions. First, the truck is driven over a speed bump at approximately 8–11 kmh (5–7 mph) in order to establish a comparison between the performance of the MR and stock dampers to transient inputs at the wheels. Second, the truck is driven along a stretch of relatively straight and level highway at a constant speed of 100 kmh (62 mph) in order to compare the performance of the two types of dampers in steady state driving conditions. Acceleration data for both driving conditions are analyzed in both time and frequency domains. The data for the speed bumps indicate that the magneto rheological dampers used (with the skyhook control policy) in this study have a small effect on the vehicle body and wheel dynamics, as compared to the passive stock dampers. The highway driving data shows that magneto rheological dampers and the skyhook control policy are effective in reducing the root mean square (RMS) of the measured acceleration at most measurement points, as compared to the stock dampers.

Development and Field Evaluation of Variable Advisory Speed Limit System for Work Zones

2007 ◽  
Vol 2015 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Eil Kwon ◽  
Daniel Brannan ◽  
Kahled Shouman ◽  
Cassandra Isackson ◽  
Bernie Arseneau
Keyword(s):  
Field Evaluation ◽  
Speed Limit ◽  
Work Zones ◽  
Limit System ◽  
Advisory Speed

scholarly journals Macroscopic Traffic Flow Characterization at Bottlenecks

2020 ◽  
Vol 6 (7) ◽  
pp. 1227-1242
Author(s):  
Amir Iftikhar ◽  
Zawar H. Khan ◽  
T. Aaron Gulliver ◽  
Khurram S. Khattak ◽  
Mushtaq A. Khan ◽  
...  
Keyword(s):  
Traffic Flow ◽  
Traffic Congestion ◽  
Urban Areas ◽  
Driver Behavior ◽  
Flow Models ◽  
Driver Response ◽  
Lwr Model ◽  
Upwind Difference Scheme ◽  
Flow Characterization ◽  
Traffic Flow Models

Traffic congestion is a significant issue in urban areas. Realistic traffic flow models are crucial for understanding and mitigating congestion. Congestion occurs at bottlenecks where large changes in density occur. In this paper, a traffic flow model is proposed which characterizes traffic at the egress and ingress to bottlenecks. This model is based on driver response which includes driver reaction and traffic stimuli. Driver reaction is based on time headway and driver behavior which can be classified as sluggish, typical or aggressive. Traffic stimuli are affected by the transition width and changes in the equilibrium velocity distribution. The explicit upwind difference scheme is used to evaluate the Lighthill, Whitham, and Richards (LWR) and proposed models with a continuous injection of traffic into the system. A stability analysis of these models is given and both are evaluated over a road of length 10 km which has a bottleneck. The results obtained show that the behavior with the proposed model is more realistic than with the LWR model. This is because the LWR model cannot adequately characterize driver behavior during changes in traffic flow.

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