Design Guidance for Freeway Main-Line Ramp Terminals

2012 ◽  
Vol 2309 (1) ◽  
pp. 48-60 ◽  
Author(s):  
Darren J. Torbic ◽  
Jessica M. Hutton ◽  
Courtney D. Bokenkroger ◽  
Marcus A. Brewer
Keyword(s):  
Field Study ◽  
Driver Behavior ◽  
Main Line ◽  
Behavioral Study ◽  
Crash Analysis ◽  
Vehicle Performance ◽  
Green Book ◽  
Improved Design ◽  
Parallel Acceleration ◽  
Design Guidance

This paper presents the results of a study to develop improved design guidance for freeway main-line ramp terminals on the basis of modern driver behavior and vehicle performance capabilities. The primary steps included a crash analysis, an observational field study, and a driver behavioral study. This research reached several key conclusions, as follows. Vehicle merging speeds tend to be closer to freeway speeds at tapered acceleration lanes than at parallel acceleration lanes. The recommended minimum lengths for acceleration lanes presented in the 2004 edition of AASHTO's A Policy on Geometric Design of Highways and Streets (Green Book) are conservative and, under certain conditions, could be reduced by 15%. In a situation in which a significant volume of trucks uses an entrance ramp, an acceleration lane length that will better accommodate trucks can be derived by using speed–distance curves developed for a range of weight-to-power ratios. The recommended minimum lengths for deceleration lanes presented in the 2004 Green Book are conservative and do not account for deceleration in the freeway. Providing deceleration lanes longer than the minimum values given in the Green Book may promote casual deceleration by exiting drivers. Several potential changes for consideration in the next edition of the Green Book are recommended on the basis of the findings and conclusions of this research.

Modeling Driver/Vehicle Performance in Emergency Maneuvers

1988 ◽  
Vol 32 (10) ◽  
pp. 573-577
Author(s):  
R. Wade Allen ◽  
Henry T. Szostak ◽  
Theodore J. Rosenthal
Keyword(s):  
Computer Simulation ◽  
Vehicle Dynamics ◽  
Driver Behavior ◽  
Vehicle Performance ◽  
Technical Aspects ◽  
Traffic Conflicts ◽  
Hazard Scenario

The combined performance of the driver and vehicle determine whether accidents result from traffic conflicts, road hazards, etc. This paper describes the driver behavior and hazard scenario aspects of a computer simulation which models both vehicle dynamics and driver steering and braking behavior. The technical aspects of the simulation have previously been published. The issue of how much the driver and vehicle contribute to accident involvement is addressed, and antilock brake evaluation is used as an example.

scholarly journals Acceleration Characteristics of Starting Vehicles

2000 ◽  
Vol 1737 (1) ◽  
pp. 58-70 ◽  
Author(s):  
Gary Long
Keyword(s):  
Field Measurements ◽  
Simulation Software ◽  
Rate Of Change ◽  
Model Parameters ◽  
Passenger Cars ◽  
Design Data ◽  
Vehicle Performance ◽  
Analysis And Design ◽  
Railroad Crossings ◽  
Green Book

Acceleration characteristics of starting vehicles are needed for many transportation analysis and design purposes involving driveways, turning bays, intersecting streets, traffic signals, railroad crossings, simulation software, and so forth. Constant acceleration is sometimes assumed, or AASHTO Green Book values based on piecewise-constant accelerations are sometimes adopted. However, continuing research has shown that linearly decreasing acceleration rates better represent both maximum vehicle acceleration capabilities and actual motorist behavior. It is not acceleration that usually is constant during speed changes; it is the rate of change in acceleration. The evolution of AASHTO acceleration values for design is traced, and the literature is reviewed for pertinent field observations. Linearly decreasing acceleration (and some deceleration) model parameters are calibrated for various sets of observational and design data. Despite published results from thousands of field measurements, the values selected for design were found to be based mostly on vehicle performance capabilities, with conjecture about how many of these capabilities are normally used by drivers. Design accelerations were found to deviate substantially from observed accelerations. At the start of motion, observed accelerations were about 15 percent faster for passenger cars and 45 percent faster for SU (single unit) trucks than design accelerations. As speed increased, observed accelerations dropped three to four times faster than design accelerations for these vehicles. Observed accelerations for WB-15 trucks began 40 percent to 75 percent slower than design accelerations, and they were considerably slower than the values in the Green Book for trucks at railroad crossings. Voids in the available information base are identified. Linearly decreasing design acceleration rates for motorists operating different classes of vehicles in different design situations are recommended, and revisions for Green Book parameters and charts are suggested. The recommended acceleration model greatly simplifies acceleration parameters but implies using different acceleration relationships for different design speeds instead of one for all.

A field study of human factors and vehicle performance associated with PHEV adaptation

Energy Policy ◽  
2016 ◽  
Vol 93 ◽  
pp. 265-277 ◽  
Author(s):  
B.C. Farhar ◽  
D. Maksimovic ◽  
W.A. Tomac ◽  
T.C. Coburn
Keyword(s):  
Human Factors ◽  
Field Study ◽  
Vehicle Performance

Field Study of Driver Exiting Behavior at Complex Interchanges

2018 ◽  
Vol 2672 (37) ◽  
pp. 19-30
Author(s):  
Bryan J. Katz ◽  
Scott O. Kuznicki ◽  
Nicholas Kehoe ◽  
Jim Shurbutt
Keyword(s):  
United States ◽  
Unmanned Aerial Vehicles ◽  
Field Study ◽  
Driver Behavior ◽  
The United States ◽  
Driving Behavior ◽  
Common Finding ◽  
Safety Issues ◽  
Lane Changes ◽  
Aerial Vehicles

A field study explored driver behavior at complex interchanges throughout the United States in order to better understand geometric, signing, and marking characteristics that influence driving behavior and lane selection. Two types of data were collected at 13 interchanges spanning four states: videos from fixed-location cameras, and videos from unmanned aerial vehicles. Findings from the study highlight common behavior as drivers negotiate complex interchanges. For each interchange studied, video was reduced to track vehicle paths throughout the study site. Although data were captured on both through and exiting traffic, the focus of this review was on the exiting vehicles. No major safety issues were observed through the study. One common finding across all sites was that exiting traffic was found to most commonly use the EXIT ONLY lane rather than the option lane. In addition, few common behaviors identified through the video show last-minute lane changes; drivers typically entered their target lane well upstream of the interchange.

The development of a risk-based approach to managing the ecological impact of pollutants in highway runoff

2008 ◽  
Vol 57 (10) ◽  
pp. 1595-1600 ◽  
Author(s):  
B. Crabtree ◽  
P. Dempsey ◽  
I. Johnson ◽  
M. Whitehead
Keyword(s):  
Ecological Risk ◽  
Ecological Impact ◽  
Research Programme ◽  
Soluble Form ◽  
Traffic Density ◽  
Highway Runoff ◽  
Pollutant Concentrations ◽  
Improved Design ◽  
The Uk ◽  
Design Guidance

In the UK, the Highways Agency is responsible for the strategic road network. It is recognised that current design guidance to control pollutants in highway runoff is out of date. A research programme is in progress to develop a better understanding of pollutants in highway runoff and their ecological impact. The paper summarises the outcome of a study to: (1) monitor pollutants in highway runoff under different climate and traffic conditions at 24 sites; (2) develop standards to assess potential ecological risks; and (3) develop a model to predict pollutant concentrations in highway runoff. Data collection and analysis of the resulting data have identified a link between pollutant concentrations and traffic density. A number of pollutants routinely present in highway runoff have been identified as posing the greatest ecological risk. Ecologically based standards for acute impacts have been derived for the soluble form of these pollutants. These standards will be used in conjunction with the model to indicate where runoff treatment may be required to mitigate ecological risk. The model and standards will be used to develop improved design guidance to protect receiving waters from pollutants in highway runoff by identifying where runoff treatment is required, and to what degree.

Driver behavior with a smartphone collision warning application – A field study

2017 ◽  
Vol 91 ◽  
pp. 361-372 ◽  
Author(s):  
Assaf Botzer ◽  
Oren Musicant ◽  
Amir Perry
Keyword(s):  
Field Study ◽  
Driver Behavior ◽  
Collision Warning

scholarly journals Conceptual Model for an Intelligent Persuasive Driver Assistant

2018 ◽  
Vol 3 (1) ◽  
pp. 157
Author(s):  
Siam Yamsaengsung ◽  
Borworn Papasratorn
Keyword(s):  
User Interfaces ◽  
Traffic Congestion ◽  
Driver Behavior ◽  
Mass Transit ◽  
Transit System ◽  
Vehicle Performance ◽  
Financial Investment ◽  
Large Cities ◽  
Initial Stage ◽  
Long Time

Traffic congestion is a serious issue for large cities.  This is especially critical for cities that has insufficient mass transit system like Bangkok.  Although transportation infrastructure projects and rail mass transit lines are being implemented, these efforts require major financial investment and take a long time to complete.  This work proposes to help reduce traffic problems through influencing a change in driver behavior.  In this initial stage, a model for an intelligent persuasive driver assistant is conceptualized as a voice-interactive smart assistant on a smartphone.  The system uses information about the driver, his physical state, vehicle performance information, and geolocation information to form persuasive strategies to influence driver behavior and to adapt user interfaces and interactions to reduce driver distraction.  Integrating these components together is expected to provide improved assistance in driving tasks and affect driving behavior changes. Keywords: intelligent driver assistant, navigation, smart assistant, persuasive technology

scholarly journals Modeling driver behavior at roundabouts: Results from a field study

2017 ◽  
Author(s):  
M. Zhao ◽  
D. Kathner ◽  
M. Jipp ◽  
D. Soffker ◽  
K. Lemmer
Keyword(s):  
Field Study ◽  
Driver Behavior

An improved design for an Scanning Tunnelling Microscope (STM) for use in a Transmission Electron Microscope (TEM)

1991 ◽  
Vol 49 ◽  
pp. 384-385
Author(s):  
W.K. Lo ◽  
J.C.H. Spence
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Mechanical Stability ◽  
Scanning Tunnelling Microscope ◽  
Reflection Mode ◽  
Specimen Holder ◽  
Transmission Electron ◽  
Scanning Tunnelling ◽  
Improved Design

An improved design for a combination Scanning Tunnelling Microscope/TEM specimen holder is presented. It is based on earlier versions which have been used to test the usefulness of such a device. As with the earlier versions, this holder is meant to replace the standard double-tilt specimen holder of an unmodified Philips 400T TEM. It allows the sample to be imaged simultaneously by both the STM and the TEM when the TEM is operated in the reflection mode (see figure 1).The resolution of a STM is determined by its tip radii as well as its stability. This places strict limitations on the mechanical stability of the tip with respect to the sample. In this STM the piezoelectric tube scanner is rigidly mounted inside the endcap of the STM holder. The tip coarse approach to the sample (z-direction) is provided by an Inchworm which is located outside the TEM vacuum.

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