scholarly journals Effects of Driver Age and Dimensions of the Stop Sign on Braking Distance Performance at Stop-Controlled Intersections

Author(s):  
Sunanda Dissanayake

Guidelines for the use of traffic control devices at stop-controlled intersections in the United States are provided in the Manual on Uniform Traffic Control Devices (MUTCD). Based on that, different dimensions of stop signs could be employed, even within the same jurisdiction. The study summarized in this paper investigated the effects of driver age and dimensions of stop signs on braking distance performance at stop-controlled intersections, while paying particular attention to older drivers. Data were collected at several stop-controlled intersections in non-residential areas in Hillsborough County, Florida, where three different sizes of stop signs (30", 36", and 48") were in use. Three driver age groups were also considered: older drivers, middle-age drivers, and young drivers. Statistical testing was used to find out whether the braking distances were different among driver age groups and also among different sizes of stop signs. Based on the observational data, it was found that older drivers had significantly longer braking distances for the largest size of the stop sign. Braking distances were also significantly different among the driver groups for the two larger sizes of the stop signs, but not for the smallest. In other words, older drivers see the larger sign and apply the brakes sooner resulting in longer braking distances. As such, the study recommends considering the replacement of smaller sizes of stop signs with the largest size in non-residential areas with a high older-driver population to increase safety at stop-controlled intersections.

Author(s):  
Johnny R. Graham ◽  
Joseph K. Harrold ◽  
L. Ellis King

Traffic pavement markings serve to regulate, guide, and channelize traffic and supplement other traffic-control devices. Because of their retroreflective properties pavement markings are critical for guidance at night, when reference objects near the edge of the roadway are difficult to see. Nighttime luminance levels provided by pavement markings that may be adequate for younger drivers may be less than adequate for older drivers. Both subjective evaluations and quantitative measures of in-place roadway markings were made to determine minimum marking retroreflectivity levels required for older drivers. In the field study more than 85 percent of subjects aged 60 years or older rated a marking retroreflectance of 100 mcd/m2/lx as adequate or more than adequate for night conditions. This base value does not include the effects of windshields and headlights that are less than clean or the variability of individual vehicle headlight performance. A comparison between the results for older drivers and the results of a similar 1989 study of younger drivers was also made. It was found that whereas the average subjective ratings were similarly distributed relative to the retroreflectivity of pavement markings, there was a significant difference in the subjective ratings made by older and younger drivers. Older drivers consistently rated the retroreflectivity of markings lower than did younger drivers.


Author(s):  
H. Gene Hawkins ◽  
Dale L. Picha ◽  
Carlos A. Lopez

The Mexican border areas of Texas possess many unique characteristics that are not present in other parts of the state. One of the most obvious is the prevalence of Spanish as the primary language. Another characteristic is the large number of drivers from Mexico. These two factors may limit the ability of border area drivers to understand traffic control devices. The research study was conducted to determine how well drivers from Mexico understand 33 of the more significant traffic control devices used in the United States and Texas. The survey utilized flash-cards with open-ended questions to assess comprehension levels. It was administered to northbound traffic with Mexican license plates at international bridges in two Texas border cities. Driver responses were recorded on audiotape and later separated into several categories, including “correct” and “partially correct.” The analysis of the responses indicate that, of the 45 questions that were asked about the 33 traffic control devices, approximately half (23) had correct and partially correct response rates of over 80 percent. Approximately a third (15) had correct response rates of over 80 percent. Many of the devices with lower comprehension levels among Mexican drivers are the same devices that have lower comprehension levels among Texas drivers.


1991 ◽  
Vol 117 (3) ◽  
pp. 311-319 ◽  
Author(s):  
Nikiforos Stamatiadis ◽  
William C. Taylor ◽  
Francis X. McKelvey

Author(s):  
Hatem Abou-Senna ◽  
Mohamed El-Agroudy ◽  
Mustapha Mouloua ◽  
Essam Radwan

The use of express lanes (ELs) in freeway traffic management has seen increasing popularity throughout the United States, particularly in Florida. These lanes aim at making the most efficient transportation system management and operations tool to provide a more reliable trip. An important component of ELs is the channelizing devices used to delineate the separation between the ELs and the general-purpose lane. With the upcoming changes to the FHWA Manual on Uniform Traffic Control Devices, this study provided an opportunity to recommend changes affecting safety and efficiency on a nationwide level. It was important to understand the impacts on driver perception and performance in response to the color of the EL delineators. It was also valuable to understand the differences between demographics in responding to delineator colors under different driving conditions. The driving simulator was used to test the responses of several demographic groups to changes in marker color and driving conditions. Furthermore, participants were tested for several factors relevant to driving performance including visual and subjective responses to the changes in colors and driving conditions. Impacts on driver perception were observed via eye-tracking technology with changes to time of day, visibility, traffic density, roadway surface type, and, crucially, color of the delineating devices. The analyses concluded that white was the optimal and most significant color for notice of delineators across the majority of subjective and performance measures, followed by yellow, with black being the least desirable.


Author(s):  
James E. Bryden ◽  
Laurel B. Andrew ◽  
Jan S. Fortuniewicz

There were 496 work zone traffic accidents on New York State Department of Transportation construction projects from 1994 through 1996. These accidents involved impacts with work zone traffic control devices and safety features; construction features, such as pavement bumps and joints; drainage features; excavations and materials; and construction vehicles, equipment, and workers. These items, which include all of the features introduced into the roadway environment by construction activity, represent one-third of all work zone accidents and 37 percent of those involving serious injury. Channelizing devices, arrow panels, signs, and other traffic control devices generally resulted in little harm when impacted. Impact attenuators, both fixed and truck mounted, also performed well. Although portable concrete barriers prevent vehicle intrusions, impacts with barrier are severe events. Barriers must be properly designed and limited to only those locations where they are needed to protect more serious hazards. Construction vehicles, equipment, and workers were involved in over 20 percent of all work zone accidents, resulting in serious injuries. Although intrusions by private vehicles into work spaces are a serious concern, construction vehicles, equipment, and workers in open travel lanes are also a serious concern. Good design of work zone traffic control plans, combined with adequate training and supervision of workers, is essential to control both concerns.


Author(s):  
Md Atiquzzaman ◽  
Huaguo Zhou

Wrong-way driving (WWD) crashes are a critical safety issue on freeways. Although these crashes are rare and random in nature, they often result in severe injuries and/or fatalities. Typically, exit ramp terminals are the initial point of entry for wrong-way (WW) drivers on freeways. Therefore, it is important for transportation agencies to identify the exit ramp terminals with higher possibility of WW entries and apply safety countermeasures to reduce the chances of their occurrence. However, the random nature of WWD crashes and the difficulty in identifying the actual entry points makes it hard for transportation agencies to assess the risk of WWD at a particular exit ramp terminal and apply countermeasures accordingly. This study developed mathematical models for predicting the risk of WW entries at the exit ramp terminals of full diamond interchanges. The geometric design features, usage of traffic control devices, area type where the interchanges are located, and annual average daily traffic (AADT) at the exit ramp terminals with or without history of WWD were used as potential predictors of WW entry. Transportation agencies can use these models to assess the risk of WW entries at the exit ramp terminals within their jurisdictions and consider possible countermeasures. They also can be applied during the design phase to determine the combination of geometric design features and traffic control devices that ensures the least possibility of WW entry.


2021 ◽  
Vol 133 ◽  
pp. 15-26
Author(s):  
Paweł Drózd ◽  
Adam Rosiński

The paper presents the issues of railway traffic control devices testing and focuses on European Train Control System (ETCS) devices widely implemented in railways. The functions of the ETCS system, principles of operation are described. The basic telegrams transmitted in the track-to-train relation are listed. The process of designing and verifying the implemented data and what parameters are checked at the stage of field tests using the locomotive is briefly described. The functional model of the SRK devices, including ETCS elements, was presented, and the close relationship between the base layer of the railway traffic control devices and the ETCS was shown. Equipment testing reduces the availability of the rail network, engages staff, and generates costs. A test generation method is presented to minimize the impact. Two indicators are proposed for reducing the set of checks, the cost of checking and the information effectiveness. The cost of checking due to the problematic estimate is generalized, divided into three groups taking into account the difficulty and resource consumption of bringing the devices to the initial state and their operation according to the test. Therefore, the obtained set of checks is suboptimal and ensures complete coverage of the functions with tests, which is essential when testing devices. The tests are carried out using available setting commands and the implementation of tasks - entry and exit routes at the station. The proposed method is universal and can be applied to any railway traffic control device, regardless of the manufacturing technology. It is a non-invasive method in the structure of the tested devices and does not require additional hardware resources.


Author(s):  
H. Gene Hawkins ◽  
Kay Fitzpatrick ◽  
Marcus A. Brewer

The 2009 United States Manual on Uniform Traffic Control Devices (MUTCD) includes guidance for the use of various types of traffic control at unsignalized intersections. Despite changes and advances in traffic engineering in recent decades, the MUTCD content related to selection of traffic control in Part 2B has seen only minor changes since 1971. The types of unsignalized traffic control addressed in the current research included no control, yield control, two-way stop control, and all-way stop control. The research team developed recommendations using information available from reviews of existing literature, policies, guidelines, and findings from an economic analysis along with the engineering judgment of the research team and panel. The researchers then developed recommended language for the next edition of the MUTCD for unsignalized intersections. This includes consideration of high-speed (rural) and low-speed (urban) conditions along with the number of legs at the intersection. Because the number of expected crashes at an intersection is a function of the number of legs, the decision on appropriate traffic control should also be sensitive to the number of legs present. The proposed language includes introductory general considerations, discusses alternatives to changing right-of-way control, and steps through the various forms of unsignalized control from least restrictive to most restrictive, beginning with no control and concluding with all-way stop control.


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