WO2015120529A1 - Procédé et appareil pour générer une représentation d'un rond-point ayant des voies de circulation en spirale - Google Patents

Procédé et appareil pour générer une représentation d'un rond-point ayant des voies de circulation en spirale Download PDF

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Publication number
WO2015120529A1
WO2015120529A1 PCT/CA2014/000112 CA2014000112W WO2015120529A1 WO 2015120529 A1 WO2015120529 A1 WO 2015120529A1 CA 2014000112 W CA2014000112 W CA 2014000112W WO 2015120529 A1 WO2015120529 A1 WO 2015120529A1
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WO
WIPO (PCT)
Prior art keywords
lane
generate
approach
vehicle
spiral
Prior art date
Application number
PCT/CA2014/000112
Other languages
English (en)
Inventor
Milton Santano Elias Carrasco
Steven Chi Kit Chan
Steven Kin-Shing CHENG
Darren Earl Brown
Robert Frank LIVINGSTON
Original Assignee
Transoft Solutions, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Transoft Solutions, Inc. filed Critical Transoft Solutions, Inc.
Priority to PCT/CA2014/000112 priority Critical patent/WO2015120529A1/fr
Publication of WO2015120529A1 publication Critical patent/WO2015120529A1/fr

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
    • E01C1/00—Design or layout of roads, e.g. for noise abatement, for gas absorption
    • E01C1/002—Design or lay-out of roads, e.g. street systems, cross-sections ; Design for noise abatement, e.g. sunken road
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]

Definitions

  • This invention relates generally to traffic intersections and more particularly to generating a representation of a roundabout having spiral circulating lanes for display via a computer.
  • Traffic intersections such as roundabouts may be designed by laying out the roadways and intersection area on a computer using a computer aided design (CAD) application.
  • a traffic roundabout is a particular type of traffic intersection having a central island surrounded by a circulatory roadway and having one or more roadways or legs for accommodating entry and/or exit lanes.
  • the circulatory roadway may have a single circulatory lane or multiple circulatory lanes, which provides increased traffic handling capacity.
  • multiple lane roundabouts may increase the possibility of collision between vehicles using the roundabout due to interweaving of vehicles between lanes, such as when attempting to access an exit lane, for example.
  • a turbo roundabout may use lane separators, lane markings or barriers to force traffic flows on spiral lane trajectories.
  • An entry lane once selected by an operator of a vehicle will limit the vehicle to a set of turning maneuvers associated with the specific entry lane. Vehicle operators must therefore make a selection of the correct entry lane in advance of accessing the roundabout, which prevents lane changes between circulatory lanes.
  • turbo roundabouts have more complex geometries than conventional roundabouts that have generally circular roundabouts.
  • Design of turbo roundabouts has been on the basis of a template or "turbo block" that provides a scaleable geometry for various configurations of turbo roundabout.
  • the use of templates to design a turbo roundabout results in lanes that have standardized lane widths sized to accommodate vehicles that can be expected during normal operation.
  • a method for generating a representation of a roundabout for display via a computer the roundabout having a central island and including at least one generally spiral circulating lane extending from a starting location on the central island and spiraling outwardly about the central island.
  • the method involves receiving at an interface of the computer, a selection of at least one design vehicle expected to use the roundabout, the design vehicle having an associated plurality of design vehicle parameters defining extents of the design vehicle.
  • the method also involves causing a processor circuit of the computer to generate a circulatory path for steering the design vehicle along the spiral circulating lane, the circulatory path being spaced outwardly from the central island to accommodate the extents of the design vehicle.
  • the method further involves receiving at the interface, orientation data defining an orientation of an approach lane of the roundabout that is generally aligned to provide access to the spiral circulating lane proximate the starting location.
  • the method also involves causing the processor circuit to generate an approach path for steering the design vehicle between the approach lane and the spiral circulatory lane.
  • the approach path includes an approach portion aligned with the approach lane to the roundabout, and a curved transition portion extending between the approach portion and the circulatory path.
  • the method further involves generating vehicle extent locations based on steering the selected design vehicle along the generated approach path and circulatory path, the vehicle extent locations representing passage of the design vehicle through the roundabout.
  • the method also involves generating a spiral circulatory lane width for the spiral circulatory lane and generating the representation of the roundabout for display on the computer based on the central island and the generated spiral circulatory lane width.
  • the spiral circulating lane may have a first loop extending from the starting location on the central island and a second loop starting at a location of overlap between the first loop and the second loop and causing the processor circuit to generate the spiral circulatory lane width may involve causing the processor circuit to generate a first lane width for the first loop and a second lane width for the second loop, each of the first and second lane widths being based on the generated vehicle extent locations.
  • Causing the processor circuit to generate the first lane width may involve generating the lane width based on generated vehicle extent locations for a first design vehicle and causing the processor circuit to generate the second lane width may involve generating the lane width based on generated vehicle extent locations for a different design vehicle.
  • the method may involve one of receiving at the interface, at least one radius associated with the curved transition portion of the approach path, and causing the processor circuit to compute at least one radius associated with the curved transition portion of the approach path based on an approach velocity of the design vehicle, and causing the processor circuit to generate the curved transition portion of the approach path may involve causing the processor circuit to generate an arc that is tangent to each of the approach portion of the approach path and the circulatory path, the arc including at least one portion having a radius corresponding to the at least one radius.
  • the method may involve causing the processor circuit to generate lane separator locations for demarcating the spiral circulating lane, the lane separator locations being based on the circulatory lane width, and causing the processor circuit to generate a break in the lane separator locations proximate the starting location of the spiral circulating lane for providing access to the spiral circulating lane.
  • Causing the processor circuit to generate the break in the lane separator locations may involve causing the processor circuit to generate the break based on design vehicle extents generated for movement of the design vehicle along the curved transition portion of the approach path.
  • the at least one design vehicle may include a first design vehicle and the method may further involve receiving at the interface, a selection of a second design vehicle, the second design vehicle having smaller extents than the first design vehicle, and causing the processor circuit to generate the break in the lane separator locations may involve causing the processor circuit to generate a break in lane separator locations based on the smaller extents of the second design vehicle such that the first design vehicle will be required to cross at least a portion of the lane separator to access the spiral circulating lane.
  • the method may involve receiving at the interface, orientation data defining an orientation of an exit of the roundabout that is generally aligned with an end of the spiral circulating lane and causing the processor circuit to generate lane separator locations may involve causing the processor circuit to generate lane separator locations for channeling vehicles traveling along the spiral circulating lane toward the exit for exiting the roundabout.
  • At least one of the approach lane and the exit lane may be disposed on a leg of the intersection that includes at least one other approach lane or exit lane and causing the processor circuit to generate lane separator locations may involve causing the processor circuit to generate lane separator locations that separate the lanes on the leg.
  • the method may involve receiving at the interface, orientation data defining an orientation of an optional exit and causing the processor circuit to generate lane separator locations may involve causing the processor circuit to generate lane separator locations that permit vehicles traveling along the spiral circulating lane toward the optional exit to either exit the roundabout on the optional exit or to continue traveling along the spiral circulatory lane.
  • Causing the processor circuit to generate the lane separator locations may involve causing the processor circuit to generate lane separator locations having a lateral extent sufficient to accommodate an elevated lane separator element.
  • the break may include a first break in the lane separator locations and the method may further involve receiving at the interface, orientation data defining an orientation of an approach lane of the roundabout that is generally aligned to provide access to the spiral circulating lane at a location distal to the starting location and may further involve causing the processor circuit to generate a second break in the lane separator locations proximate the location distal to the starting location for providing access to the spiral circulating lane.
  • Generating the circulatory path may involve causing the processor circuit to read from the plurality of design vehicle parameters, a track width parameter associated with a front axle and wheels of the design vehicle, causing the processor circuit to generate a circulatory path that is offset from the central island by a distance corresponding to half of the track width, and causing the processor circuit to generate vehicle extent locations may involve steering the selected design vehicle to cause a center of the front axle of the design vehicle to follow the circulatory path.
  • Causing the processor circuit to generate vehicle extent locations may involve causing the processor circuit to generate a plurality of vehicle extent locations corresponding to various extents of the design vehicle and to select vehicle extent locations within the plurality of vehicle extent locations that define a swept path of the design vehicle for passage of the design vehicle along the generated approach path and the generated circulatory path.
  • Causing the processor circuit to generate the spiral circulatory lane width may involve causing the processor circuit to offset vehicle extent locations that define the swept path of the design vehicle to determine a plurality of locations defining the lane width.
  • the at least one spiral circulating lane may include a first spiral circulating lane and may further include a second spiral circulating lane extending from a respective starting location on the central island and contiguous with the first spiral circulating lane and the method may further involve causing the processor circuit to generate a circulatory path for steering the design vehicle along the second spiral circulating lane, the circulatory path being spaced outwardly from the central island to accommodate the extents of the design vehicle, causing the processor circuit to receive at the interface, orientation data defining an orientation of an approach lane of the roundabout that may be generally aligned to provide access to the second spiral circulating lane proximate the starting location, and causing the processor circuit to generate an approach path for steering the design vehicle between the approach lane and the second spiral circulatory lane.
  • the approach path may include an approach portion aligned with the approach lane to the roundabout, and a curved transition portion extending between the approach portion and the circulatory path.
  • the method may also involve generating vehicle extent locations based on steering the selected design vehicle along the generated circulatory path and approach path, the vehicle extent locations representing passage of the design vehicle through the roundabout, and generate a spiral circulatory lane width for the second spiral circulatory lane.
  • Causing the processor circuit to generate the approach lane may involve causing the processor circuit to generate at least two approach lanes including a first approach lane aligned to permit entry to one of the first and second spiral circulating lanes a second approach lane aligned to permit entry to the other of the first and second spiral circulating lanes.
  • the method may involve causing the processor circuit to generate lane separator locations for demarcating between the contiguous spiral circulating lanes, the lane separator locations being based on the respective circulatory lane widths, and generate a break in the lane separator locations proximate each respective starting location of the first and second spiral circulating lanes for providing access to the respective spiral circulating lanes, the break being operable to prevent access by vehicles traveling in the second approach lane.
  • the method may involve causing the processor circuit to extend the central island to at least partly occupy regions proximate the starting location of the spiral circulatory lane that are not traversed by the design vehicle when accessing the spiral circulatory lane.
  • the method may involve causing the processor circuit to provide for passage of a large vehicle other than the at least one design vehicle by one of causing the processor circuit to reduce a size of the central island to provide an apron located inwardly of the spiral circulatory lane, the apron being mountable to permit the large vehicle to encroach on the apron when using the roundabout, and causing the processor circuit to increase a size of the spiral circulating lane to provide for passage of the large vehicle on the spiral circulating lane.
  • an apparatus for generating a representation of a roundabout for display the roundabout having a central island and including at least one generally spiral circulating lane extending from a starting location on the central island and spiraling outwardly about the central island.
  • the apparatus includes a processor circuit operably configured to receive at an interface, a selection of at least one design vehicle expected to use the roundabout, the design vehicle having an associated plurality of parameters defining extents of the design vehicle.
  • the processor circuit is also operably configured to generate a circulatory path for steering the design vehicle along the spiral circulating lane, the circulatory path being spaced outwardly from the central island to accommodate the extents of the design vehicle.
  • the processor circuit is further operably configured to receive at the interface, orientation data defining an orientation of an approach lane of the roundabout that is generally aligned to provide access to the spiral circulating lane proximate the starting location, and to generate an approach path for steering the design vehicle between the approach lane and the spiral circulatory lane.
  • the approach path includes an approach portion aligned with the approach lane to the roundabout, and a curved transition portion extending between the approach portion and the circulatory path.
  • the processor circuit is also operably configured to generate vehicle extent locations based on steering the selected design vehicle along the generated circulatory path and approach path, the vehicle extent locations representing passage of the design vehicle through the roundabout.
  • the processor circuit is further operably configured to generate a spiral circulatory lane width for the spiral circulatory lane, and generate the representation of the roundabout for display based on the central island and the generated spiral circulatory lane width.
  • the spiral circulating lane may have a first loop extending from the starting location on the central island and a second loop starting at a location of overlap between the first loop and the second loop and the processor circuit is operably configured to generate the spiral circulatory lane width by generating a first lane width for the first loop and a second lane width for the second loop, each of the first and second lane widths being based on the generated vehicle extent locations.
  • the processor circuit may be operably configured to generate the first lane width by generating the lane width based on generated vehicle extent locations for a first design vehicle and the processor circuit is operably configured to generate the second lane width by generating the lane width based on generated vehicle extent locations for a different design vehicle.
  • the processor circuit may be operably configured for one of receiving at the interface, at least one radius associated with the curved transition portion of the approach path, and computing at least one radius associated with the curved transition portion of the approach path based on an approach velocity of the design vehicle, and the processor circuit may be operably configured to generate the curved transition portion of the approach path by generating an arc that is tangent to each of the approach portion of the approach path and the circulatory path, the arc including at least one portion having a radius corresponding to the at least one radius.
  • the processor circuit may be operably configured to generate lane separator locations for demarcating the spiral circulating lane, the lane separator locations being based on the circulatory lane width, and generate a break in the lane separator locations proximate the starting location of the spiral circulating lane for providing access to the spiral circulating lane.
  • the processor circuit may be operably configured to generate the break in the lane separator locations by generating the break based on design vehicle extents generated for movement of the design vehicle along the curved transition portion of the approach path.
  • the at least one design vehicle may include a first design vehicle and the processor circuit may be operably configured to receive a selection of a second design vehicle at the interface, the second design vehicle having smaller extents than the first design vehicle, and the processor circuit may be operably configured to generate the break in the lane separator locations based on the smaller extents of the second design vehicle such that the first design vehicle will be required to cross at least a portion of the lane separator to access the spiral circulating lane.
  • the processor circuit may be operably configured to receive at the interface, orientation data defining an orientation of an exit of the roundabout that is generally aligned with an end of the spiral circulating lane and to generate lane separator locations by causing generating lane separator locations for channeling vehicles traveling along the spiral circulating lane toward the exit for exiting the roundabout.
  • At least one of the approach lane and the exit lane may be disposed on a leg of the intersection that includes at least one other approach lane or exit lane and the processor circuit may be operably configured to generate lane separator locations by causing the processor circuit to generate lane separator locations that separate the lanes on the leg.
  • the processor circuit may be operably configured to receive at the interface, orientation data defining an orientation of an optional exit and to generate lane separator locations by generating lane separator locations that permit vehicles traveling along the spiral circulating lane toward the optional exit to either exit the roundabout on the optional exit or to continue traveling along the spiral circulatory lane.
  • the processor circuit may be operably configured to generate lane separator locations having a lateral extent sufficient to accommodate an elevated lane separator element.
  • the break may include a first break in the lane separator locations and the processor circuit may be operably configured to receive at the interface, orientation data defining an orientation of an approach lane of the roundabout that is generally aligned to provide access to the spiral circulating lane at a location distal to the starting location and to generate a second break in the lane separator locations proximate the location distal to the starting location for providing access to the spiral circulating lane.
  • the processor circuit may be operably configured to generate the circulatory path by reading from the plurality of design vehicle parameters, a track width parameter associated with a front axle and wheels of the design vehicle, generating a circulatory path that is offset from the central island by a distance corresponding to half of the track width, and generating vehicle extent locations by steering the selected design vehicle to cause a center of the front axle of the design vehicle to follow the circulatory path.
  • the processor circuit may be operably configured to generate vehicle extent locations by generating a plurality of vehicle extent locations corresponding to various extents of the design vehicle and selecting vehicle extent locations within the plurality of vehicle extent locations that define a swept path of the design vehicle for passage of the design vehicle along the generated approach path and the generated circulatory path.
  • T e processor circuit may be operably configured to generate the spiral circulatory lane width by offsetting vehicle extent locations that define the swept path of the design vehicle to determine a plurality of locations defining the lane width.
  • the at least one spiral circulating lane may include a first spiral circulating lane and may further include a second spiral circulating lane extending from a respective starting location on the central island and contiguous with the first spiral circulating lane and the processor circuit may be operably configured to generate a circulatory path for steering the design vehicle along the second spiral circulating lane, the circulatory path being spaced outwardly from the central island to accommodate the extents of the design vehicle, receive at the interface.
  • the processor circuit may also be operably configured to receive orientation data defining an orientation of an approach lane of the roundabout that is generally aligned to provide access to the second spiral circulating lane proximate the starting location, and to generate an approach path for steering the design vehicle between the approach lane and the second spiral circulatory lane.
  • the approach path may include an approach portion aligned with the approach lane to the roundabout, and a curved transition portion extending between the approach portion and the circulatory path.
  • the processor circuit may also be operably configured to generate vehicle extent locations based on steering the selected design vehicle along the generated circulatory path and approach path, the vehicle extent locations representing passage of the design vehicle through the roundabout, and generate a spiral circulatory lane width for the second spiral circulatory lane.
  • the processor circuit may be operably configured to generate the approach lane by generating at least two approach lanes including a first approach lane aligned to permit entry to one of the first and second spiral circulating lanes and a second approach lane aligned to permit entry to the other of the first and second spiral circulating lanes.
  • the processor circuit may be operably configured to generate lane separator locations for demarcating between the contiguous spiral circulating lanes, the lane separator locations being based on the respective circulatory lane widths, and generate a break in the lane separator locations proximate each respective starting location of the first and second spiral circulating lanes for providing access to the respective spiral circulating lanes, the break being operable to prevent access by vehicles traveling in the second approach lane.
  • the processor circuit may be operably configured to extend the central island to at least partly occupy regions proximate the starting location of the spiral circulatory lane that are not traversed by the design vehicle when accessing the spiral circulatory lane.
  • the processor circuit may be operably configured to provide for passage of a large vehicle other than the at least one design vehicle by one of reducing a size of the central island to provide an apron located inwardly of the spiral circulatory lane, the apron being mountable to permit the large vehicle to encroach on the apron when using the roundabout, and increasing a size of the spiral circulating lane to provide for passage of the large vehicle on the spiral circulating lane.
  • a non-transient computer readable medium encoded with codes for directing a processor circuit to generate a representation of a roundabout for display via a computer, the roundabout having a central island and including at least one generally spiral circulating lane extending from a starting location on the central island and spiraling outwardly about the central island.
  • the codes direct the processor circuit to receive at an interface, a selection of at least one design vehicle expected to use the roundabout, the design vehicle having an associated plurality of parameters defining extents of the design vehicle.
  • the codes also direct the processor circuit to generate a circulatory path for steering the design vehicle along the spiral circulating lane, the circulatory path being spaced outwardly from the central island to accommodate the extents of the design vehicle.
  • the codes further direct the processor circuit to receive at the interface, orientation data defining an orientation of an approach lane of the roundabout that is generally aligned to provide access to the spiral circulating lane proximate the starting location, and to generate an approach path for steering the design vehicle between the approach and the spiral circulatory lane.
  • the approach path includes an approach portion aligned with the approach lane to the roundabout, and a curved transition portion extending between the approach portion and the circulatory path.
  • the codes also direct the processor circuit to generate vehicle extent locations based on steering the selected design vehicle along the generated circulatory path and approach path, the vehicle extent locations representing passage of the design vehicle through the roundabout.
  • the codes further direct the processor circuit to generate a spiral circulatory lane width for the spiral circulatory lane, and to generate the representation of the roundabout for display on the computer based on the central island and the generated spiral circulatory lane width.
  • Figure 1 is a block diagram of an apparatus for generating a representation of a roundabout
  • FIG. 2 is a block diagram of a processor circuit for implementing the apparatus shown in Figure 1;
  • Figure 3 is a representation of a roundabout generated by the processor circuit shown in Figure 2;
  • Figure 4 is a flowchart depicting blocks of code for directing the processor circuit of
  • Figure 2 to implement a process for generating the representation of the roundabout shown in Figure 3
  • Figure 5 is a side view of design vehicles used in generating the representation of the roundabout shown in Figure 3
  • Figure 6 is a table listing parameters for the design vehicles shown generally in Figure
  • Figure 7 is a flowchart depicting blocks of code for directing the processor circuit shown in Figure 2 to implement a process for generating a circulatory path;
  • Figure 8 is an enlarged view of the circulatory path shown in the representation of
  • Figure 9 is a flowchart depicting blocks of code for directing the processor circuit shown in Figure 2 to implement a process for generating an approach path;
  • Figure 10 is an enlarged view of the approach path generated by the process shown in
  • Figure 9 is a flowchart depicting blocks of code for directing the processor circuit shown in Figure 2 to implement a process for generating lane separator locations;
  • Figure 12 is a representation of a roundabout generated by the processor circuit shown in Figure 2 in accordance with an alternative embodiment of the invention.
  • Figure 13 is an enlarged view of a portion of the roundabout shown in Figure 3;
  • Figure 14 is a representation of a roundabout generated in accordance with an another embodiment of the invention
  • Figure 15 is a representation of a roundabout generated in accordance with a further embodiment of the invention.
  • Figure 16 is a view of a portion of a central island of the roundabout representation shown in Figure 15.
  • the apparatus 100 includes a CAD system 102 having an input 104 for receiving operator input from an input device such as a keyboard 106 and/or a pointing device 108.
  • the pointing device 108 may be a computer mouse, trackball, or digitizing tablet, or other device operable to produce pointer movement signals.
  • the CAD system 102 also includes a display 114 and an output 110 for producing output data for displaying an image of the geometric layout on the display.
  • the CAD system 102 further includes a plotter 116 and an output 112 for producing output data for causing the plotter to print a hardcopy representation of the representation.
  • the CAD system 102 also includes an interface 118 that provides access to the CAD system functions implemented by the CAD system 102.
  • the apparatus 100 further includes a roundabout layout functional block 122, which provides functions for causing the CAD system 102 to generate the representation of the roundabout.
  • the roundabout functional block 122 interfaces with the CAD system through the interface 118.
  • the CAD system may be provided by causing a computer to execute CAD system software such as the AutoCAD ® software application available from Autodesk Inc. of San Rafael, CA, USA.
  • AutoCAD provides drawing elements such as lines, polylines, circles, arcs, and other complex elements.
  • Customization of AutoCAD may be provided through ObjectARX (AutoCAD Runtime Extension), which is an application programming interface (API) that permits access to a class-based model of AutoCAD drawing elements.
  • Customization code may be written in a programming language such as C++, which may be compiled to provide the roundabout layout functionality represented in the functional block 122 shown in Figure 1.
  • CAD systems such as MicroStation sold by Bentley Systems Inc. of Exton, PA, USA, provide similar CAD functionality and interfaces for customization.
  • using existing CAD software applications to provide standard CAD functionality allows operators to produce drawing files representing a roundabout layout.
  • the resulting drawing files may also be saved in such a manner to permit other operators who do not have access to the roundabout layout functional block 122, to view and/or edit the drawings.
  • the CAD system functions may be provided in a web-based mapping program such as Google Maps or Google Earth.
  • Google maps provide an API for interacting with the map data on the Google Map servers and provide functionality that allows others to display additional information to displayed map data provided by Google. Processor Circuit
  • the processor circuit 200 includes a microprocessor 202, a program memory 204, a variable memory 206, a media reader 210, and an input output port (I/O) 212, all of which are in communication with the microprocessor 202.
  • Program codes for directing the microprocessor 202 to carry out various functions are stored in the program memory 204, which may be implemented as a random access memory (RAM) and/or a hard disk drive (HDD), or a combination thereof.
  • the program memory 204 includes a first block of program codes 214 for directing the microprocessor 202 to perform operating system functions and a second block of program codes 216 for directing the microprocessor 202 to perform CAD system functions for implementing the CAD system 102 shown in Figure 1.
  • the program memory 204 also includes a third block of program codes 218 for directing the microprocessor 202 to perform roundabout functions related to generating features of the roundabout and a fourth block of program codes 220 for directing the microprocessor 202 to provide an interface between the CAD functions and the roundabout functions.
  • the media reader 210 facilitates loading program codes into the program memory 204 from a computer readable medium 230, such as a CD ROM disk 232, or a computer readable signal 234, such as may be received over a network such as the internet, for example.
  • a computer readable medium 230 such as a CD ROM disk 232
  • a computer readable signal 234 such as may be received over a network such as the internet, for example.
  • the I/O 212 includes the input 104 for receiving operator input from the keyboard 106 and pointing device 108.
  • the I/O 212 further includes the outputs 110 and 112 for producing output data for driving the display 114 and plotter 116.
  • the variable memory 206 includes a plurality of storage locations including a location 250 for storing a design vehicle database, a location 252 for storing vehicle path data, a location 254 for storing various vehicle path parameters, a location 256 for storing approach and exit lane data, a location 258 for storing central island layout data, a location 260 for storing vehicle extent data, and a location 262 for storing roundabout layout data representing the roundabout.
  • the variable memory 206 may be implemented in RAM memory, flash memory, or as a hard drive, for example. Roundabout representation
  • the roundabout 300 has a central island 302 and includes a generally spiral circulating lane 304 extending from a starting location 306 on the central island.
  • the spiral circulating lane 304 spirals outwardly about the central island 302 and in the embodiment shown extends one full loop and a further partial loop around the central island.
  • the central island 302 includes a first semicircular portion 308 and a second semicircular portion 310 that lie on either side of an axis 312.
  • the first semicircular portion 308 has a radius Ri and the second semicircular portion 310 has a radius R 2 , where the radius R 2 is greater than the radius Ri.
  • the first semicircular portion 308 has a center at 309 and the second semicircular portion 310 a center at 311 , where the respective centers lying on the axis 312 and being spaced apart.
  • the starting location 306 may be defined in terms of an angular offset ⁇ with respect to the axis 312.
  • the elements making up the central island 302 are thus defined by the axis 312, the radii Ri, /3 ⁇ 4, center locations 309 and 311 , and the starting location angular offset ⁇ . These elements may be defined by coordinates in an x-y Cartesian coordinate system 340 and may be stored in the central island layout data location 258 of the variable memory 206.
  • the central island 302 may be constructed using spiral segments that have a progressively increasing radius such as a clothoid spiral having a radius that changes linearly with length along the spiral.
  • FIG. 4 a flowchart depicting blocks of code for directing the processor circuit 200 (shown in Figure 2) to implement a process for generating the representation of the roundabout 300 is shown generally at 400.
  • the blocks of the process 400 generally represent codes that may be read from the computer readable medium 230, and stored in the program memory 204, for directing the microprocessor 202 to perform various functions related to generating the central island layout.
  • the actual code to implement each block may be written in any suitable program language, such as C++, for example.
  • the process begins at block 402, which directs the microprocessor 202 to receive a selection of a design vehicle expected to use the roundabout 300.
  • the design vehicle is a standard 40 foot bus, which is shown in plan view at 348.
  • the design vehicle 348 is characterized by a plurality of design vehicle parameters defining the configuration, steering movement, and extents of the design vehicle.
  • a side view representation of the design vehicle 348 is shown and a standard passenger car design vehicle is shown at 440.
  • the design vehicles 348 and 440 are taken from the American Association of State Highway and Transportation Officials (AASHTO) library of standard design vehicles.
  • Each of the design vehicles 348 and 440 are defined by a plurality of design vehicle parameters stored in the database 250 (shown in Figure 2).
  • the parameter listing 450 includes a steering lock angle parameter ( ⁇ ⁇ ) 452 representing an angle through which the steering of the vehicle is capable of turning from a straight ahead condition and a lock-to-lock time (t L ) parameter 452 representing a time to steer the vehicle through a full steering angle range.
  • ⁇ ⁇ steering lock angle parameter
  • t L lock-to-lock time parameter 452 representing a time to steer the vehicle through a full steering angle range.
  • the value of t L may be measured for each design vehicle under driving conditions, or a default value (such as 6 seconds) may be assumed for the design vehicle
  • the parameter listing 450 also includes dimensions for overall vehicle length 456, front overhang 458, body width 460, and wheelbase 462.
  • the front overhang dimension 458 is taken from the center of the front wheel to the front extent of the vehicle.
  • the wheelbase dimension 462 is the dimension between front and rear axles of the vehicle, and for the case of the Bus 40 design vehicle is taken between the center of the front wheel and the center of a rear axle group, which includes two spaced apart axles each having 4 wheels.
  • the parameter listing 450 also includes parameters associated with a front axle group, including the number of wheels per axle 466 and a front track dimension 464 ⁇ T F ).
  • the track dimension 464 is taken as the distance between outer edges of the tire tread measured across the axle.
  • track dimensions generally refer to a distance between respective centers of the outer wheel tire tread, but for intersection design the outside of the tire tread is relevant for defining intersection features.
  • the parameter listing 450 also includes parameters associated with a rear axle group, including the number of wheels per axle 470 and a rear axle track dimension T R 468.
  • the parameter listing 450 further includes a number of parts parameter 472.
  • the design vehicle may be an articulated vehicle (not shown), in which case the number of parts parameter 472 would be set to "2".
  • the number of parts parameter 472 is set to "1 " indicating that the vehicles are unarticulated.
  • the parameter listing 450 would include additional parameters for the vehicle such as a pivot location, and parameters for the trailer such as trailer length, and articulating angle.
  • the database 250 (shown in Figure 2) in the variable memory 206 stores sets of parameters for a plurality of design vehicles, such as the parameters 450 shown in Figure 5.
  • design vehicles such as the parameters 450 shown in Figure 5.
  • libraries of various standard design vehicles are implemented in the AutoTURN ® software product available from Transoft Solutions Inc. of British Columbia, Canada.
  • the libraries include commonly used design vehicles for different countries and also provide for custom definition of vehicles not available in the standard libraries.
  • Block 402 of the process 400 may thus direct the microprocessor 202 to receive a selection of one of the design vehicles from the database 250 for generation of the representation of the roundabout 300.
  • the process 400 then continues at block 402, which directs the microprocessor 202 to generate a circulatory path for steering the design vehicle along the spiral circulating lane 304.
  • the circulatory path is shown at 350 and extends between the points 349 and 351.
  • the circulatory path 350 is spaced outwardly from the central island 302 to accommodate the extents of the design vehicle 348 while steering around the central island 302.
  • the circulatory path 350 radius R 3 is selects to space a rear wheel such that the rear wheels of the design vehicle 348 remain spaced inwardly from the central island 302 by a clearance offset Si from the central island.
  • the clearance offset Si is read from the location 254 of the variable memory 206 and may be provided by user input.
  • Block 402 also directs the microprocessor 202 to store the radius R3 and coordinates defining the points 349 and 351 in the vehicle path data location 252 of the variable memory 206.
  • Block 406 then directs the microprocessor 202 to receive orientation data defining an orientation of an approach lane 314 of the roundabout 300.
  • the orientation of the approach lane 314 is defined with respect to a reference line 342 and the received orientation data identifies the reference line 342 and the approach lane offset with respect to the reference line.
  • the orientation data is stored in the location 256 of the variable memory 206.
  • additional orientation data defining additional lanes may also be received.
  • the approach lane 314, a second approach lane 318, and an exit lane 320 are disposed on an intersection leg 316 that is aligned with the reference line 342.
  • the intersection leg 316 further includes a median 352 separating the approach lane 314 and the exit lane 320.
  • Additional reference lines 344 and 346 may also be received defining orientations for additional intersection legs.
  • the reference line 344 provides an orientation of a second intersection leg 326 including an exit lane 322 generally aligned with an end 324 of the spiral circulating lane 304, a second exit lane 328, an approach lane 330, and a median 354 between the exit lane 322 and the approach lane 330.
  • the reference line 346 provides an orientation for an additional intersection leg 332 including entry lanes 334 and 336, an exit lane 338 generally aligned with an end 324 of the spiral circulating lane 304, and a median 356 between the entry lane 334 and the exit lane 338.
  • Data defining the reference lines 344 and 346 and the legs 326 and 332 may also be stored in the location 256 of the variable memory 206.
  • the starting location 306 is aligned with a line 307 extending from a side of the median 352 that bounds the approach lane 314.
  • the angle ⁇ may thus be selected to cause the starting location 306 to be aligned with the line 307, or the starting location may be defined by intersection of the line 307 with the central island 302.
  • the process 400 then continues at block 408, which directs the microprocessor 202 to generate an approach path for steering the design vehicle 348 between the approach lane 314 and the spiral circulatory lane 304.
  • the approach path includes an approach portion 358 that extends between the points 357 and 359.
  • the approach portion 358 is a straight line offset parallel to the reference line 342 and provides a clearance S2 between the design vehicle 348 and the median 352.
  • the approach portion 358 may be curved.
  • the approach path also includes a curved transition portion 360 extending between the points 359 and 349 and joining the approach portion 358 to the circulatory path 350.
  • the curved transition portion 360 is constructed as an arc of radius R 4 , where the radius R4 may be provided by an operator of the apparatus 100.
  • the curved transition portion 360 is generated by constructing a circle of radius R 4 tangent to the approach portion 358 and then moving the circle until it touches the circulatory path 350 at a single tangent point (i.e. the point 349).
  • Block 408 then directs the microprocessor 202 to store information defining the approach portion 358 and curved transition portion 360 of the approach path in the vehicle path data location 252 of the variable memory 206.
  • the curved transition portion 360 may be non-circular and may include curved portions having differing or progressively changing radii, for example.
  • Block 410 then directs the microprocessor 202 to generate vehicle extent locations 362 and 364 for the design vehicle 348.
  • the vehicle extent locations 362 and 364 are based on steering the design vehicle 348 along the generated approach portion 358, curved transition portion 360, and circulatory path 350, and represent passage of the design vehicle through the roundabout 300.
  • the design vehicle 348 includes a steerable front wheels 366 and in this embodiment front wheels are steered such that a reference location on the vehicle at the center of the front axle follows the paths 358, 360, and 350. In other embodiments alternative reference locations on the design vehicle 348 may be selected.
  • Block 410 further directs the microprocessor 202 to store the vehicle extents in the location 260 of the variable memory 206. ln the embodiment shown in Figure 3, the front and rear wheels of the vehicle are used to generate the vehicle extents 362 and 364, but in other embodiments other features such as a protruding point on a wide load or other protruding vehicle feature that would need clearance from curbs, walls, barriers, or other structures associated with the roundabout 300 may be used to generate vehicle extents. Details of a process for generating vehicle extents will be described later herein.
  • the process 400 then continues at block 412, which directs the microprocessor 202 to generate a spiral circulatory lane width W for the spiral circulatory lane 304.
  • the outer extent of the spiral circulating lane 304 is demarcated by a lane separator 368 and the width of the lane W is shown between the central island 302 and the lane separator.
  • the width W is generated by offsetting the vehicle extents 362 by a clearance offset S3 read from the location 254 of the variable memory 206.
  • the lane width may be computed from the relation:
  • Block 412 further directs the microprocessor 202 to store the lane width W in the roundabout layout data location 262 of the variable memory 206.
  • Block 414 then directs the microprocessor 202 to generate the representation of the roundabout 300 for display based on the elements making up the central island 302 (stored in the location 258) and the generated spiral circulatory lane width (stored in the location 262). The representation may be displayed on the display 114 or output to the plotter 116 (shown in Figure 1 ) as a hardcopy plan of the roundabout 300.
  • a flowchart depicting blocks of code for directing the processor circuit 202 to implement a process for generating the circulatory path 350 (block 404 of the process 400 in Figure 4) is shown at 404 in Figure 7.
  • the process 404 for begins at block 500, which directs the microprocessor 202 to generate a bicycle model for the design vehicle 348.
  • the circulatory path 350 is shown in greater detail and extends between the points 349 and 351 .
  • a bicycle model 520 of the design vehicle 348 is shown at a design vehicle location 552 and includes a front wheel 522 and a rear wheel 524, which are separated by a distance 530 corresponding to a wheelbase dimension (Parameter 462 in Figure 6) of the design vehicle.
  • the wheelbase of the bicycle model 520 is indicated by the line 530.
  • the wheelbase dimension is taken from the center of the front wheel 366 and the center of a rear axle group, which includes two spaced apart axles 526 and 528 each having 4 wheels.
  • the front and rear wheels 522 and 524 of the are centered between the respective front and rear wheels of the design vehicle 348 (i.e. the front and rear wheels are each located at half of the respective track dimensions 464 and 468 shown in Figure 6).
  • the front wheels of the design vehicle 348 are steerable and the corresponding front wheel 522 of the bicycle model 520 is also steerable while the rear wheel 524 of the bicycle model is not steerable.
  • the design vehicle 348 may have steerable rear wheels, in place of or in addition to steerable front wheels, and the bicycle model 520 may thus include a corresponding steerable rear wheel 524 or steerable front and rear wheels.
  • the design vehicle parameters stored in the design vehicle database 250 may be used to determine corresponding locations of the wheels of the design vehicle 348.
  • the front left hand wheel 366 of the design vehicle 348 is spaced apart from the front wheel 522 of the bicycle model by half of the front track width dimension 464 in a direction perpendicular to the wheelbase line 530.
  • Locations of other wheels and vehicle extents, such as a right hand rear wheel 532, may be similarly computed using the design vehicle parameters offset from the location of the rear wheel 524 of the bicycle model 520.
  • a representative bicycle model may be generated that includes a bicycle model portion for the tractor portion of the design vehicle and a bicycle model portion for the trailer portion of the design vehicle.
  • the tractor bicycle model portion will be generally as shown in Figure 8 at 520 but would include a pivot location, while the trailer bicycle model portion would include a fixed rear wheel separated by a trailer wheelbase distance from the pivot location.
  • a bicycle model simplifies computation of coordinate locations for vehicle extents along the curved transition path 360, thereby providing improved computational efficiency.
  • the design vehicle 348 and parameters 450 may be used directly in implementing the process 410 i.e. without the use of a bicycle model.
  • the process 404 then continues at block 502 which directs the microprocessor 202 to read the radius Ri of the portion first semicircular portion 308 of the central island 302 from the location 258 of the variable memory 206, read the offset Si from the location 254, and to read the track width T R of the rear wheels of the design vehicle 348 from the design vehicle database 250.
  • Block 504 then directs the microprocessor 202 to generate the a circulatory path centerline 550, which is spaced outwardly from the portion first semicircular portion 308 of the central island 302 in accordance with the formula:
  • Block 506 then directs the microprocessor 202 to locate the rear wheel 524 of the bicycle model 958 on the circulatory path centerline 550 oriented perpendicular to the radial line R c .
  • Block 506 then directs the microprocessor 202 to read a wheelbase value WB from the design vehicle database 250 and to determine a front wheel location for the bicycle model 520.
  • the location of the front wheel 522 is determined by generating a line of length WB extending outwardly from a center location of the rear wheel 524 in a direction aligned with the rear wheel.
  • the front wheel steering angle ⁇ is given by the formula:
  • ⁇ is the steering angle of the front wheel 522.
  • the location of the front wheel 522 of the bicycle model 520 defines the radius 3 ⁇ 4 for the full extent of the circulatory path 350 between the points 349 and 351.
  • the center of the front axle of the design vehicle will be located on the circulatory path and the steering angle ⁇ will be the same as for the location 552.
  • FIG. 9 A flowchart depicting blocks of code for directing the processor circuit 202 to implement a process for generating the approach path (block 408 of the process 400 in Figure 4) is shown in Figure 9.
  • the process 408 begins at block 590, which directs the microprocessor 202 to receive operator input of a turning radius R 4 for generating the curved transition path 360 and a clearance offset value S 2 .
  • the parameters /3 ⁇ 4 and S2 are stored in the location 254 of the variable memory 206.
  • Block 592 then directs the microprocessor 202 to compute a minimum turn radius R min .
  • the minimum turn radius may be computed in accordance with a formula, such as the formula:
  • v is a speed of the design vehicle 348 through the turn
  • f is a side friction factor associated with a surface of the roundabout 300
  • e is a superelevation parameter defining the cross-slope of the roadway.
  • the superelevation e is expressed as a percentage value and when e is positive the superelevation defines a slope that assists t e design vehicle in completing the turn, while negative values of e define a slope that make completion of the turn more difficult for the design vehicle. Note that for units other than meters and kilometers, the values of the numerical constants in Eqn 4 would have to be modified accordingly.
  • Various other formulae may be used to compute R min .
  • the computed R m ; bend value is stored in the location 254 of the variable memory 206.
  • Block 594 then directs the microprocessor 202 to determine whether the turn radius R 4 input by the operator is less then the minimum turn radius R min , in which case block 596 directs the microprocessor 202 to write the value of R min into the location 254 as the turning radius R 4 .
  • block 596 may direct the microprocessor 202 to generate a warning signal for displaying a warning to inform the operator that the selected turn radius is not a feasible turn radius.
  • the warning signal may cause an audible tone to be generated and/or causing an operator interface to be displayed to alert the operator. If at block 594 the turn radius R 4 input by the operator is not less then the minimum turn radius R min the process continues at block 598 with the value of R 4 provided by the operator input at block 590.
  • the approach path is shown in enlarged view in Figure 10.
  • the approach path includes the approach portion 358 extending between the points 357 and 359.
  • the approach portion 358 is aligned with the reference line 342 and spaced apart by half the width of the median 352 and clearance S 2 between the design vehicle 348 and the median 352.
  • the approach path also includes the curved transition portion 360 extending between the points 359 and 349. The curved transition portion 360 merges into the circulatory path 350 at the point 349.
  • Block 598 then directs the microprocessor 202 to generate an arc of radius R 4 that is tangent to the approach portion 358 and the circulatory path 350.
  • a circle 580 of radius R 4 may be constructed and located tangent to the approach portion 358 and then moved upwards in small increments until the circle touches the circulatory path 350 at a single point.
  • the curved transition portion 360 may include a spiral transition portion extending along the curved transition portion from the point 359 during which time a steering angle of the front wheel 522 of the bicycle model 520 is incremented to cause the front wheel to moves along the circular arc of radius R 4 .
  • the curved transition portion 360 may include two or more arcs having different radii.
  • a flowchart depicting blocks of code for directing the processor circuit 202 to implement a process for generating lane separator locations is shown at 650 in Figure 11.
  • the lane separators may be implemented as painted lines on the roadway, a mountable curb, a space between lanes, or any other barrier between adjacent lanes.
  • the process begins at block 652, which directs the microprocessor 202 to generate the lane separator 368 for demarcating the spiral circulating lane 304.
  • the lane separator 368 between the first loop and second loop of the spiral circulating lane 304 is based on the circulatory lane width W, and is aligned with a circular arc having a center location 309 and a radius of Ri + W.
  • Block 654 then directs the microprocessor 202 to generate a break 372 in the lane separator 368 proximate the starting location 306 for providing access to the spiral circulating lane 304 for the design vehicle entering the roundabout 300 on the approach lane 314.
  • the break 372 is shown as a broken line and extends from the starting location 306 on the central island 302 to a point 374, and block 654 directs the microprocessor 202 to generate the break 372 based on the extents 364 generated for movement of the design vehicle along the curved transition portion 360 of the approach path.
  • the point 374 is disposed with a clearance offset S 4 from a point 376 where the vehicle extents 364 cross the circular arc generated in block 652.
  • the process 650 then continues at block 656 which directs the microprocessor 202 to generate a lane separator 378 for channeling vehicles traveling along the spiral circulating lane 304 toward the exit lane 322 for exiting the roundabout 300.
  • the lane separator 378 extends from the lane separator 368 and is spaced apart from the vehicle extents 364 by a clearance offset Ss- Block 658 then directs the microprocessor 202 to generate a further lane separator 380 separating the lanes on the second intersection leg 326.
  • the lane separator 380 extends from the lane separator 378 and is also spaced apart from the vehicle extents 364 by the clearance offset S5.
  • the lane separator 378 generated by implementing block 656 defines an optional exit for the design vehicle 348 traveling along the spiral circulating lane 304.
  • the vehicle may either exit the roundabout 300 on the lane exit lane 322 of the leg 326 or continue traveling in the spiral circulating lane 304 and take a later exit, such as the exit lane 320 of the intersection leg 316, the exit lane 338 of the additional intersection leg 332, or the second exit lane 328 of the second intersection leg 326.
  • the lane separator 378 however prevents the design vehicle 348 from exiting from the first loop of the spiral circulating lane 304 onto the second exit lane 328 of the second intersection leg 326.
  • the lane separator 378 defines a forced exit from the roundabout 300 on the second exit lane 328 and prevents the vehicle from crossing into the exit lane 322 of the second intersection leg 326
  • some or all of the lane separator locations 368, 378, and 380 are generated to have sufficient lateral extent (commonly referred to as "gore") to accommodate an elevated lane separator element when the roundabout 300 is constructed.
  • Elevated lane separators are effective in preventing vehicles from making potentially dangerous lane changes, such as changing lanes from the first loop to the second loop of the spiral circulating lane 304 or from changing lanes from the exit lane 322 to the second exit lane 328.
  • the elevated lane separators still permit larger vehicles traveling at low speed to mount the lane separator when the width of the lane is insufficient to permit passage of the vehicle.
  • the lane width W is generated based on the design vehicle 348, which is a large 40 foot bus and the lane separators 368, 378, 380 and break 372 are generated based on the same design vehicle.
  • An alternative roundabout embodiment is shown at 700 in Figure 12. Referring to Figure 12, in the alternative embodiment 700, a break 702 in the lane separator 368 is generated based on a smaller design vehicle, such as the passenger vehicle shown at 440 in Figure 5.
  • the design vehicle 440 is moved from the approach lane 314 to the spiral circulating lane 304 as described in the processes 400 and 408 above generating vehicle extents 706.
  • the break 702 in the lane separator 368 is generated based on the extents 706, in this embodiment having a clearance offset S 6 from a point 708, where the vehicle extents cross the circular arc.
  • the break 702 in the lane separator 368 is smaller for the roundabout embodiment 700, due to use of the smaller standard passenger vehicle 440 for generating the break.
  • the smaller break 702 has the advantage of providing less clearance for passenger vehicles than the break 372 when entering the spiral circulating lane 304.
  • block 654 may further direct the microprocessor 202 to extend the central island by a portion 707 to at least partly occupy regions proximate the starting location of the spiral circulatory lane that are be not traversed by the design vehicle 440 when accessing the spiral circulatory lane 304.
  • the process 650 then continues at block 660, which directs the microprocessor 202 to generate a second break 720 in the lane separator 368 to provide access for a design vehicle 722 to the inner loop of the spiral circulating lane 304 at a location distal to the starting location 306.
  • the design vehicle 722 is a standard passenger vehicle, but in other embodiments could be a vehicle such as the design vehicle 348 shown in Figure 5.
  • Block 660 directs the microprocessor 202 to generate an approach path 724 by implementing the process 408 shown in Figure 4 and Figure 9 and to generate vehicle extents 726 and 728 by implementing the process in block 410 (shown in Figure 4).
  • Block 660 further directs the microprocessor 202 to generate the second break 720 based on the extents 726 and 728, which may be spaced from the extents by clearance offsets S 7 and S 8 .
  • the spiral circulating lane 304 has a first loop extending from the starting location 306 on the central island 302 and a second loop starting at a location of overlap 370 between the first loop and the second loop.
  • the process 404 shown in Figure 7 is used to generate the lane width l/l for the first loop, as disclosed above. In one embodiment the process 404 may also be used to generate a second lane width for the second loop based on generated vehicle extents.
  • the design vehicle 348 and bicycle model 520 are shown located in the second loop of the spiral circulating lane 304.
  • the rear wheel 524 of the bicycle model 520 is spaced inwardly from the lane separator 368 by a clearance offset S 5 and half of the rear track width T R for the design vehicle 348.
  • the bicycle model 520 is oriented as described above in connection with the process 404 and provides a location for a circulatory path 600 for the front wheel 522 of the bicycle model 520 to follow along the second loop of the spiral circulating lane 304.
  • Vehicle extents 602 and 604 are generated as described above for successive movements of AD of the bicycle model 520 and the vehicle extent 604 is offset by a clearance Ss to generate an outer curb 606 for the roundabout 300 such that the lane width of the second loop of the 304 has a width W 2 .
  • the lane width W 2 may be different to the lane width W for the first loop, thus providing a more compact layout of the roundabout 300.
  • a third design vehicle (not shown) may be used to generate the width W 2 of the second loop of the spiral circulating lane 304.
  • the third design vehicle may for example be a larger vehicle that would not be accommodated in the first loop of the spiral circulating lane 304. Accordingly, in some embodiments the generated width W 2 may be greater than the width W of the first loop of the spiral circulating lane 304.
  • the lane width W 2 of the second loop of the spiral circulating lane 304 may be generated by implementing the possesses 400, 404, and 408 shown in Figure 4, 7, and 9 for movement of a design vehicle from the second approach lane 318 of the intersection leg 316 to the second loop of the spiral circulating lane 304.
  • the lane widths W and W 2 generated in accordance with the process of Figure 9 may have calculated values that would not be convenient or practical for construction of the roundabout. For example if a lane width based on the design vehicle were to have a calculated value of 3.73 meters, block 412 of the process 400 shown in Figure 4 may additionally provide for selection of a more convenient or standard lane width, such as 3.8 meters, for example. The selection may be implemented automatically or provisions for an operator override may be implemented.
  • the width W of the inner loop of the spiral circulating lane 304 of the roundabouts 300 of Figure 3 and 700 of Figure 12, is generated based on the design vehicle 348 in the embodiments disclosed herein. In some cases, it may be desirable to provide for passage of larger design vehicles that may use the roundabout 300.
  • the first semicircular portion 308 of the roundabout 300 is shown with a large design vehicle 800 travelling through the roundabout within the lane separator 368 and generating vehicle extents 802 and 804.
  • the vehicle extents 802 are spaced inwardly from the lane separator 368 by the clearance offset S 3 and the large design vehicle 800 is oriented as described above in connection with block 508 of the process 404 (shown in Figure 7).
  • a rear wheel 806 of the design vehicle 800 encroaches on the first semicircular portion 308 of the central island 302.
  • the process 404 may be modified to cause the microprocessor 202 to offset the vehicle extents 804 inwardly by a clearance offset Sg and reduce the size of the central island 302 to provide an apron 808 located inwardly of the spiral circulatory lane 304.
  • the apron 808 may be constructed to be mountable by the large design vehicle 800 when travelling through the roundabout 300.
  • the apron 808 may be constructed from a material that differs from surfaces of the spiral circulating lane 304, such that other smaller vehicles are discouraged from using the apron.
  • an easily mountable curb may be provided at an outer edge 810 of the apron 808.
  • An inner edge 812 of the apron lies along the edge of the first semicircular portion 308 of the central island 302 and may be constructed as a raised curb.
  • the apron 808 may be generated as described above and implemented as an extension to the spiral circulating lane 304.
  • apron 808 may have the same surface construction as the spiral circulating lane 304 and may either be marked using lane markings or simply implemented as an extended spiral circulating lane 304.
  • the roundabout embodiment 300 shown in Figure 3 has a single axis 312 defining the central island 302, a single starting location 306 on the central island, and a single generally spiral circulating lane 304 having a first and second loop.
  • an alternative roundabout embodiment is shown generally at 830 and includes a first axis 832 and a second axis 834.
  • a first semicircular portion 836 having a center 838 on the first axis 832 and a radius Ri and a second semicircular portion 840 having a center 842 on the second axis 834 and a radius R 2 together define a central island 844, where Ri - R 2 -
  • the spiral circulating lanes 846 and 848 are thus separate contiguous lanes nested within each other extending about the central island 844 from the respective starting locations 850 and 852.
  • the lane widths Wi and W 2 of the lanes 848 and 846 may be the same and may be generated by implementing the process 400 for each of the starting locations.
  • the centers 838 and 842 are spaced apart by the lane width l VV
  • the various processes described above may be implemented for generating lane separators, breaks, and lane widths as described above in connection with the roundabout 300.
  • the lane widths Wi and W 2 of the lanes 846 and 848 may be different.
  • the lane width of the lane 848 may initially be set to Wi and may increase progressively along the lane to match a greater lane width W ⁇ .
  • another roundabout embodiment is shown generally at 870 and includes a first axis 872, a second axis 874, and a third axis 876.
  • the first axis 872 defines a generally circular sector 878 having a center 880 on the first axis and a radius Ri and the second axis 834 defines a second semicircular portion 840 having a center 842 on the second axis and a radius R ⁇ .
  • a first generally circular sector portion 878 having a center 880 on the first axis 872, a second generally circular sector portion 882 having a center 884 on the second axis 874, and a third generally circular sector portion 886 having a center 888 on the third axis 876 together define a central island 890.
  • Three generally spiral circulating lanes 892, 894, and 896 extend from respective starting locations 898, 900, and 902 on the central island 844. The spiral circulating lanes 892, 894, and 896 are thus separate contiguous lanes nested within each other extending about the central island 890 from the respective starting locations 898, 900, and 902.
  • the generally circular sectors 878, 882, and 886 are generated using a combination of arcs having different radii and centers.
  • an example of a geometric process for generating the sector 878 is shown at 940.
  • the sector 878 lies between the third axis 876 and the first axis 872 and the starting location 902 lies on the third axis.
  • An arc of radius Ri at center 880 extends back from the location 898 through an angle of 60° and a line 942 is constructed through the center 880.
  • Another arc of radius Ri at center 888 extends back from the location 902 through an angle of 60°.
  • An intersection between the third axis 876 and the line 942 defines a center 944 for a radius ?
  • Each of the remaining sectors 882 and 886 may be constructed in the same manner, along with the spiral circulating lanes 892, 894, and 896.
  • the various processes described above may be implemented for generating lane separators, breaks, and lane widths as described above in connection with the roundabout 300.
  • the disclosed embodiments facilitate layout of a roundabout having spiral circulating lanes based on generation of vehicle paths through the roundabout and swept paths or vehicle extents generated for movement of various design vehicles along the vehicle paths.

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Abstract

L'invention concerne un procédé et un appareil pour générer une représentation d'un rond-point pour l'affichage par l'intermédiaire d'un ordinateur. Le rond-point possède un îlot central et une voie de circulation globalement en spirale formant une spirale vers l'extérieur autour de l'îlot central. Le procédé comprend d'amener un circuit de processeur à générer une voie de circulation pour diriger un véhicule de calcul le long de la voie de circulation en spirale et de recevoir des données d'orientation définissant l'orientation d'une voie d'approche fournissant l'accès à la voie de circulation, et d'amener le circuit de processeur à générer une voie d'approche pour la direction entre la voie d'approche et la voie de circulation en spirale. Le procédé comprend également de générer des emplacements d'étendue de véhicule pour le véhicule de calcul représentant le passage du véhicule de calcul à travers le rond-point, de générer une largeur de voie de circulation en spirale, et de générer la représentation du rond-point pour l'affichage sur l'ordinateur sur la base de l'îlot central et de la largeur de voie de circulation en spirale générée.
PCT/CA2014/000112 2014-02-13 2014-02-13 Procédé et appareil pour générer une représentation d'un rond-point ayant des voies de circulation en spirale WO2015120529A1 (fr)

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Publication number Priority date Publication date Assignee Title
ES2784464A1 (es) * 2019-03-25 2020-09-25 Univ Alcala Henares Sistema y procedimiento de señalización y regulación de tráfico para rotondas
CN112553989A (zh) * 2021-01-26 2021-03-26 内蒙古真金种业科技有限公司 一种生态型路口立交式环岛

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Publication number Priority date Publication date Assignee Title
WO2010060180A1 (fr) * 2008-11-26 2010-06-03 Transoft Solutions, Inc. Procédé et appareil d’affichage d’une représentation d’intersection routière
WO2012135947A1 (fr) * 2011-04-08 2012-10-11 Transoft Solutions, Inc. Processus et appareil servant à générer une enveloppe balayée tridimensionnelle d'un véhicule
WO2013188944A1 (fr) * 2012-06-20 2013-12-27 Transoft Solutions, Inc. Procédé et appareil de génération par ordinateur d'un tracé géométrique représentant un îlot central d'un rond-point de circulation

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Publication number Priority date Publication date Assignee Title
WO2010060180A1 (fr) * 2008-11-26 2010-06-03 Transoft Solutions, Inc. Procédé et appareil d’affichage d’une représentation d’intersection routière
WO2012135947A1 (fr) * 2011-04-08 2012-10-11 Transoft Solutions, Inc. Processus et appareil servant à générer une enveloppe balayée tridimensionnelle d'un véhicule
WO2013188944A1 (fr) * 2012-06-20 2013-12-27 Transoft Solutions, Inc. Procédé et appareil de génération par ordinateur d'un tracé géométrique représentant un îlot central d'un rond-point de circulation

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2784464A1 (es) * 2019-03-25 2020-09-25 Univ Alcala Henares Sistema y procedimiento de señalización y regulación de tráfico para rotondas
WO2020221951A1 (fr) * 2019-03-25 2020-11-05 Universidad De Alcalá Système et procédé de signalisation et de régulation de trafic pour des ronds-points
CN112553989A (zh) * 2021-01-26 2021-03-26 内蒙古真金种业科技有限公司 一种生态型路口立交式环岛

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