Abstract:
The automated lane management assist method, data structure and system receive unprocessed lane-specific limited-access highway information, including lane use and speed limits, from freeway transportation management centers or traffic management centers, process and convert the unprocessed information to a form that assists in the selection of driving lanes and target speeds for vehicles, and communicate the processed information to the vehicles by suitable means. The Guidance Assist Vehicle Module combines the processed information with information from the vehicle and the driver including the information on appropriate lane changes and speed commands to the vehicle.

Description:
CROSS REFERENCE OF RELATED APPLICATIONS 
       [0001]    This patent application is a continuation-in-part application of nonprovisional patent application Ser. No. 14/108,710, which claims priority to provisional patent application Ser. No. 61/747,331 filed on Dec. 30, 2012, provisional patent application Ser. No. 61/750,426 filed on Jan. 9, 2013, and provisional patent application Ser. No. 61/827,067 filed on May 24, 2013, and this patent application also claims the benefit of the provisional patent application Ser. No. 61/911,298 filed on Dec. 3, 2013, all of which are hereby incorporated by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention was not made pursuant to any federally-sponsored research and/or development. 
         [0003]    The present invention relates to a method and system for collection and processing of the real-time traffic data and using the data in assisting the drivers of vehicles, and the intelligent in-vehicle systems in partially or fully automated vehicles, to select a specific lane for vehicle travel on limited access highways, as well as a recommended vehicle speed. 
       BACKGROUND 
       [0004]    The patent application Ser. No. 14/108,710 titled “Management Center Module for Advanced Lane Management Assist for Automated Vehicles and Conventionally Driven Vehicles” describes a process (ALMA) for improving the selection of the most appropriate freeway lane to select and a target speed for that lane. The use of data from a traffic management center TMC is a key source of information for that process. The prior patent application describes a functional architecture that includes the following modules:
       ALMAMC—ALMA Management Center Module   SD—Static Database   ODE—Operator Data Entry   GAVM—Guidance Assist Vehicle Module       
 
         [0009]    The prior patent application describes the overall ALMA functional architecture and provides the computational algorithms, procedures and requirements for the ALMAMC module. The prior patent application also describes the background leading to the need for ALMA and the benefits to be derived from it. Using the data output from the ALMAMC, ODE and SD, and the data structures described in the prior patent application, this patent application describes the computational algorithms, procedures and requirements for the GAVM module. 
         [0010]    The GAVM module combines information from the ALMAMC together with information from the vehicle and the driver. It provides information on appropriate lane changes and speed commands to the vehicle. Physically it may be a separate computer based unit, or alternatively the software may be incorporated into the vehicle&#39;s Navigation and Control System. “Cloud” computation, external to the vehicle may also be employed. A typical computer-based unit may include a processor or processing system, data and information storage, an input-output system, and a user interaction system. 
       SUMMARY 
       [0011]    It is an object of the present invention to achieve, provide, and facilitate:
       The collection and processing of real-time data from the ALMAMC, SD and ODE described above.   The further processing of this data to provide the vehicle&#39;s control system or the driver with information on the most appropriate lane to select and the desired speed for that lane.       
 
         [0014]    The vehicle control will be determined not only based on direct external parameters such as those provided by the vehicle sensors, but also the data collected and processed by the TMCs from its own vehicle detectors, cameras, incident reports, scheduled roadway closures and TMC operator input. Additionally, the vehicle&#39;s operator may put in some information about the vehicle&#39;s characteristics, passenger occupancy and willingness to take highways, pay tolls, and other driving preferences. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    These features, aspects and advantages of the novel Advanced Lane Management Assist for Automated Vehicles will become further understood with reference to the following description and accompanying drawings where 
           [0016]      FIG. 1  is the block diagram representation of the ALMA Relationships; 
           [0017]      FIG. 2  is the flowchart for the Zone and Sequence Identification Module; 
           [0018]      FIG. 3  shows the percentage of vehicles operating at a speed which is below a speed represented by the speed limit plus the difference between the actual motorist speed and the speed limit. 
       
    
    
     DESCRIPTION 
       [0019]    Introduction. The patent application titled “Management Center Module for Advanced Lane Management Assist for Automated Vehicles and Conventionally Driven Vehicles” describes a functional architecture for conventionally driven vehicles and for partially and fully automated vehicles to select the most appropriate freeway lane and the most appropriate speed for that lane. The architecture contains the functional module “Guidance Assist Vehicle Module”. This patent application provides the details for that module. The prior patent application also describes the emerging increased intensity in the use of traffic lane management controls by operating agencies and the need by motorists and automated vehicles for improved in-vehicle information on lane use. 
         [0020]    Basic Functions.  FIG. 1  (reproduced from the prior patent application with appropriate identification notation) provides a functional architecture and the basic data flow relationships for the entire process of transforming information developed by traffic management centers (TMCs) into information that drivers or automated vehicles may use to assist in lane selection and the development of a target speed for that lane. This patent application focuses on the details of the Guidance Assist Vehicle Module  205  (GAVM) in that figure. The basic function of the GAVM  205  is to obtain information from the ALMA Management Center  202 , (ALMAMC) and combine it with information from the vehicle operator and from the vehicle itself to provide the lane guidance information. ALMA provides information to vehicles to enable them to respond to information from the freeway traffic management center in a way that is similar or superior to the way that a human driver would respond to the commands. 
         [0021]    Inputs to the GAVM  205  from the ALMA Management Center  202  include the following:
       Lane speed and other lane based traffic parameters;   Vehicle class. Lanes may be restricted for use by certain vehicle classes*;   Vehicle overheight and overweight restrictions; Lane closure commands;   Lane closure commands*;   Permitted use of shoulders for travel*;   Availability of required vehicle occupancy*; and   Speed limits by lane*.       
 
         [0029]    *This information may vary by time-of-day or by traffic conditions. 
         [0030]    Information from the vehicle  101 ,  102  and the operator  204  includes:
       Vehicle location   Driver aggressiveness preferences;   Identification of desired freeway entry and exit locations   Availability of toll tag;   Willingness of vehicle operator to pay toll; and   Number of passengers.       
 
         [0037]    Vehicles using ALMA require a route development capability (navigation system). Using the information described above, the GAVM  205  provides information to select appropriate lanes and provide target speeds. If the GAVM  205  determines that restrictions on the freeway prevent the completion of the planned route, the GAVM  205  notifies the vehicle&#39;s navigation system that a different path is required. 
         [0038]    Functional Architecture.  FIG. 1 , reproduced from patent application titled “Management Center Module for Advanced Lane Management Assist for Automated Vehicles and Conventionally Driven Vehicles” shows the principal data flow relationships among ALMA modules and the freeway traffic management center  201  and the vehicle navigation and control system  101 ,  102 . The ALMA Vehicle Module  205  (ALMAVM) combines information from the ALMAMC  202  together with information from the vehicle navigation and control system  101 ,  102  and the driver  204 . It provides information on appropriate lane changes and speed recommendations to the vehicle control system  102  or to the driver. Physically it may be a separate computer based unit, or alternatively the software may be incorporated into the vehicle&#39;s Navigation and Control System  101 ,  102 . Cloud computing facilitates other physical arrangements. The prior patent application describes the relationship and function of the other modules. 
         [0039]    The ALMA concept utilizes a data structure (physical division of the freeway into information related segments.) This data structure, consisting essentially of barrels and zones is described in detail in the prior patent application. 
         [0040]    Data Inputs to the ALMAVM. Table 1 describes a number of the data inputs into the GAVM  205  from the functional modules in  FIG. 1 . 
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 ALMAVM 205 Data Inputs 
               
             
          
           
               
                   
                 DATA SOURCE 
               
             
          
           
               
                   
                   
                   
                 ODI 
                 VNC 
               
               
                   
                   
                   
                 Operator 
                 Vehicle 
               
               
                   
                   
                   
                 Data 
                 Navigation 
               
               
                   
                   
                 ALMAMC 
                 Entry 
                 and Control 
               
               
                 Symbol 
                 Parameter 
                 202 
                 204 
                 101, 102 
               
               
                   
               
             
          
           
               
                 AVL 
                 Average vehicle length 
                 √ 
                   
                   
               
               
                 AVSPD 
                 Average lane speed in  
                 √ 
                   
                   
               
               
                   
                 barrel 
                   
                   
                   
               
               
                 BARNORM 
                 Barrel incident status 
                 √ 
                   
                   
               
               
                 CURLANE 
                 Lane vehicle is  
                   
                   
                 √ 
               
               
                   
                 currently in 
                   
                   
                   
               
               
                 Distset 
                 Distance to begin  
                   
                 √ 
                   
               
               
                   
                 search for zone next  
                   
                   
                   
               
               
                   
                 to exit location 
                   
                   
                   
               
               
                 EC 
                 Exit open 
                 √ 
                   
                   
               
               
                 EXZ 
                 Zone vehicle exits  
                   
                   
                 √ 
               
               
                   
                 from path 
                   
                   
                   
               
               
                 H 
                 Overheight restriction 
                   
                 √ 
                   
               
               
                 INCZONE 
                 Closed lane(s) in this  
                 √ 
                   
                   
               
               
                   
                 zone 
                   
                   
                   
               
               
                 LC 
                 Lane commands 
                 √ 
                   
                   
               
               
                 LFD 
                 Lane flow direction 
                 √ 
                   
                   
               
               
                 LSS 
                 Lane control ATM  
                   
                   
                   
               
               
                   
                 command from TMC 
                   
                   
                   
               
               
                 LVR 
                 Lane vehicle  
                 √ 
                   
                   
               
               
                   
                 requirements 
                   
                   
                   
               
               
                 PO 
                 Number of vehicle  
                   
                 √ 
                   
               
               
                   
                 occupants 
                   
                   
                   
               
               
                 SPPUSH 
                 Incremental speed 
                   
                 √ 
                   
               
               
                 SPTMC 
                 Zone speed 
                 √ 
                   
                   
               
               
                 TRA 
                 Toll rate by lane 
                 √ 
                   
                   
               
               
                 TTA 
                 Set of types of toll tags  
                   
                 √ 
                   
               
               
                   
                 available to vehicle 
                   
                   
                   
               
               
                 TTU 
                 Does driver want to  
                   
                 √ 
                   
               
               
                   
                 use toll tag for trip 
                   
                   
                   
               
               
                 VC 
                 Vehicle class 
                   
                 √ 
                   
               
               
                 VH 
                 Vehicle height 
                   
                 √ 
                   
               
               
                 VS 
                 Vehicle speed 
                   
                   
                 √ 
               
               
                 VW 
                 Vehicle weight 
                   
                 √ 
                   
               
               
                 ZC 
                 Zone that vehicle is  
                   
                   
                 √ 
               
               
                   
                 currently in 
                   
                   
                   
               
               
                 ZE 
                 Entry zone to path 
                   
                   
                 √ 
               
               
                   
               
             
          
         
       
     
         [0041]    ALMAVM Top Level Module and Processes. ALMA executes its processes through software modules. The in-vehicle processes are computed in the following order: 
       Module 1—Sequence Identification 
       [0042]    Based on barrel and zone information from the vehicle, this module schedules the sequence of computations. 
       Module 2—Operator and Vehicle Constraints 
       [0043]    The lane selection process is influenced and constrained by vehicle characteristics and vehicle operator preferences with regard to the payment of tolls. These constraints include:
       The availability of an appropriate toll tag and the operators desire to elect a toll facility   Vehicle satisfaction of height restrictions   Vehicle satisfaction of weight restrictions   Vehicle satisfaction of lane use restrictions. These include adherence to the type of lane use (e.g. HOV) and satisfaction of passenger occupancy requirements       
 
       Module 3—Adjustment for Vehicle Exit 
       [0048]    Modules 3 and 4 provide the vehicle with instructions to select the most appropriate lane. The modules identify a “target” or recommended lane to which the vehicle should move. In some cases, the vehicle will traverse the entire portion of the path from the vehicle entry point until the last zone in the barrel. In other cases, the vehicle will exit the path prior to the last zone in the barrel. Module 3 develops the guidance instructions to accommodate vehicles that will exit the freeway shortly. Module 4 develops the guidance instructions for other vehicles. 
       Module 4—Lane Guidance 
       [0049]    Module 4 identifies the target lane. It first identifies allowable target lanes based on the presence of incidents, lane drops and vehicle exit requirements. Two alternative sets of lane selection rules are provided by Module 4.3.A and Module 4.3.B. 
         [0050]    Module 4.3.A provides a simple set of rules for selecting the target lane. These rules do not consider operator speed preferences, weather and roadway alignment. Module 5 is used in conjunction with this module to select target speed. 
         [0051]    Module 4.3.B considers vehicle operator speed preferences, weather and roadway alignment. It provides target lane and target speed. Other rule sets are possible. 
       Module 5—Speed Guidance for Module 4A 
       [0052]    For the lane selected in Module 4A, a rule set for the target or recommended speed for the target lane is described. Other rule sets are possible. If the current zone lane speed for the targeted lane exceeds the speed limit for that lane, the module targets the vehicle speed as the speed limit. If the lane speed is lower than the speed limit, the targeted speed is set to the current speed plus an increment. The increment is intended to push the vehicles speed into a vehicle following condition to avoid unnecessary gaps being developed in the traffic stream. 
         [0053]    ALMAVM Module Process Descriptions 
         [0054]    Module 1—Sequence Identification 
         [0055]      FIG. 2  shows the flow chart for this module. The data structures are described in the patent application titled  Management Center Module For Advanced Lane Management Assist for Automated Vehicles and Conventionally Driven Vehicles.    
         [0056]    Module 1.1  301  Inputs from Vehicle 
         [0057]    The vehicle&#39;s mapping function must correlate the vehicle map links with the ALMA barrel and zone structure. Thus when the vehicle is in an entry zone for the ALMA controlled roadway, the vehicle must identify the entry zone and barrel to ALMA. The vehicle must continue to identify the barrel and zone to ALMA. When the calculation is performed for Zone Z (the zone that is subsequent to the zone the vehicle is currently in) the module awaits a new input from the vehicle in order to start the next computational sequence. 
         [0058]    Module 1.2  302  Determine if Vehicle is on the Controlled Network or is in an Entry Zone for the Controlled Network 
         [0059]    Module 1.3  303  Select the Zone for which the Guidance Computation is to be Performed 
         [0060]    Guidance computations are to be performed for a zone (Z) that is downstream of the zone in which the vehicle is currently located (ZC). The downstream zone is identified from its position in the path set (identified as ZP in Section 4). 
         [0061]    Module 1.4  304  Perform Calculations for Zone Z for Modules 2, 3, 4, and 5 
         [0062]    This module transfers the sequence of computations to the modules that will develop the guidance information for Zone Z. 
         [0063]    Module 1.5  305  Test to Determine Whether Zone Z is the Last Zone in the Barrel that the Vehicle&#39;s Path will Traverse 
         [0064]    If the vehicle will traverse no additional zones in the barrel after Zone Z, no future computations need be performed for this barrel, and a search is instituted for an entry zone in the next barrel in the vehicle&#39;s projected route. The last zone that the vehicle will traverse in the barrel is identified as the last element in path set ZP. Note that Zone Z may also serve as an entry zone to the next barrel. 
         [0065]    Module 1.6  306  Reset Barrel Index 
         [0066]    If the vehicle will enter the last zone in barrel then reset the barrel index to indicate that vehicle will have left barrel after it has exited the zone (the next barrel must be re-identified by the inputs from the vehicle (Module 1.1). 
         [0067]    Module 2 Operator and Vehicle Constraints 
         [0068]    This module determines which lanes in a barrel may or may not be available based on the vehicles classification, characteristics, toll tag availability, and the operator&#39;s willingness to pay the toll. Barrels should be defined such that these characteristics are homogeneous throughout the barrel. Below is a representative listing of the pseudocode for these sub-modules. 
         [0069]    Module 2 Pseudocode 
         [0070]    ‘Module 2.1 Toll Tag and Vehicle Occupancy Clearance for Lane 
         [0000]    
       
         
               
             
           
               
                   
               
             
             
               
                 For L = LSTART(B) to LN 
               
               
                 TTC(B,L) = 0 
               
               
                 If TTL(B,L) = 0 ‘Chck for HOT lane 
               
               
                  then if LTYPE = HOT    ‘Indicates that lane is HOT 
               
               
                    then if PO ≧ ON  ‘Sufficient occupancy so toll not needed 
               
               
                          then TTC(B,L) = 1 
               
               
                    else ‘Check for other than HOT 
               
               
                 If TTL = Y 
               
               
                  and (A ε TTA)  ‘A is the type of toll tag. It is tested for membership in the set 
               
               
                 TTA 
               
               
                     and (TTU = Y) 
               
               
                        then TTC(B,L) =1 
               
               
                 else if 
               
               
                 TTL = N  ‘No toll tag required 
               
               
                  then TTC(B,L) = 1 
               
               
                 Next L 
               
               
                   
               
               
                 ‘Note: 
               
               
                 TTA and TTU must be entered by vehicle operator 
               
             
          
         
       
     
         [0071]    ‘Module 2.2 Overheight Clearance for Barrel 
         [0000]    
       
         
               
               
             
           
               
                   
               
             
             
               
                   
                 OC(B) = 0 
               
               
                   
                 If VC = A then OC(B) = 1 ‘Passenger cars are exempt from check 
               
               
                   
                  else if VH ≦ VHL(B) then OC(B) = 1 
               
               
                   
               
               
                 ‘Note: 
               
               
                 VH must be entered by vehicle operator 
               
             
          
         
       
     
         [0072]    ‘Module 2.3 Overweight Clearance for Barrel 
         [0000]    
       
         
               
               
             
           
               
                   
               
             
             
               
                   
                 OWC(B) = 0 
               
               
                   
                 If VC = A then OWC(B) = 1 ‘Passenger cars are exempt from check 
               
               
                   
                  else if VW ≦ VWL(B) then OWC(B) = 1 
               
               
                   
               
               
                 ‘Note: 
               
               
                 VW must be entered by vehicle operator 
               
             
          
         
       
     
         [0073]    ‘Module 2.4 Vehicle Classification Test 
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                   
                 For L = LSTART(B) to LN 
               
               
                   
                   
                 LA(B,L) = 0 
               
               
                   
                   
                 If VC = A then ‘passenger car guidance 
               
               
                   
                   
                  If (LVR(L) ≠ B) and (LVR(L) ≠ C) and (LVR(L) ≠ E) 
               
               
                   
                   
                   then LA(B,L) = 1 
               
               
                   
                   
                 If VC = B then ‘bus guidance 
               
               
                   
                   
                  If (LVR(L) ≠ A) and (LVR(L) ≠ C) 
               
               
                   
                   
                   then LA(B,L) = 1 
               
               
                   
                   
                 If VC = C then ‘bus guidance ‘truck guidance 
               
               
                   
                   
                  If (LVR(L) ≠ A) and (LVR(L) ≠ B) 
               
               
                   
                   
                   then LA(B,L) = 1 
               
               
                   
                   
                 Next L 
               
               
                   
                   
               
             
          
         
       
     
         [0074]    Module 2.5 Determine Allowable Lanes Based on Vehicle, Operator and Roadway Constraints 
         [0000]    
       
         
               
               
             
           
               
                   
               
             
             
               
                   
                 If ACT(B) =1 and Z = ZE(B) then ‘barrel is active 
               
               
                   
                 For L = LSTART(B) to LN 
               
               
                   
                 VOK(B,L) = 0 
               
               
                   
                 If (LOK(L) = 1) and (TTC(B,L) = 1) and (OC(B) = 1) and  
               
               
                   
                 (OWC(B) = 1) and (LA(B,L) =1) then VOK(B,L) = 1 
               
               
                   
                 Next L 
               
               
                   
               
             
          
         
       
     
         [0075]    Module 2.1 Toll Tag Clearance for Lane 
         [0076]    The module checks to see that the vehicle has an appropriate toll tag if required by the lane and that the operator is willing to pay the toll. 
         [0077]    Module 2.2 Overheight Clearance for Barrel 
         [0078]    For vehicles other than passenger cars, the module compares vehicle height with barrel requirements. 
         [0079]    Module 2.3 Overweight Clearance for Barrel 
         [0080]    For vehicles other than passenger cars, the module compares vehicle weight with barrel requirements. 
         [0081]    Module 2.4 Vehicle Classification Test 
         [0082]    The module compares the vehicle&#39;s classification (passenger car, bus, truck) with lane restrictions that may apply. 
         [0083]    Module 2.5 Determine Allowable Lanes Based on Vehicle, Operator and Roadway Constraints 
         [0084]    The module combines the results of modules 2.1, 2.2, 2.3 and 2.4 to determine the lanes that may be used by the vehicle. 
         [0085]    Module 3 Adjustment for Vehicle Exit 
         [0086]    If the vehicle is to exit the barrel prior to the last link in the barrel, this module develops the appropriate instruction for lane guidance. Below is a representative listing of the pseudocode for this module. 
         [0087]    Module 3 Pseudocode 
         [0088]    Module 3 provides guidance for vehicles that exit the barrel prior to the last zone in the barrel. It activates when the vehicle is sufficiently close to the exit to require preparation to access the exit ramp. 
         [0089]    Module 3.1 Check Exit Open 
         [0090]    The planned exit EXZ is the zone that services the exit ramp. This zone is identified by the vehicle. Information on exits that are closed (EC(B,Z)=0) are communicated to the vehicle from the ALMAMC. They are identified as zones in the barrel that access the exit ramp.
       If EXZ not ε{EC(B)} then go to Module 3.2 ‘exit is open Else EXC=True ‘EXC is the ID for the zone servicing the exit ramp ‘Notification must be sent to the vehicle that the ramp serviced by zone EXZ is closed.       
 
         [0092]    In that case, a new value for EXZ is expected from the vehicle. 
         [0093]    Module 3.2 Check Exit Proximity 
         [0000]    
       
         
               
             
               
               
             
               
             
               
               
             
           
               
                   
               
             
             
               
                 ‘Check to see if vehicle is within Distset of zone servicing exit ramp. Distset is in earth arc 
               
               
                 degrees, One degree is 0.0105 miles. 
               
               
                 ‘Compute distance between vehicle and zone serving planned exit (EXZ) 
               
               
                 DTE = ((PELAT−VLAT) 2  +((PELON − VLON)*cos(VLAT)) 2 ) 0.5   
               
             
          
           
               
                 If DTE &gt; Distset then go to Module 3.3 else  
                   ‘Vehicle too far from exit to require 
               
               
                   
                   proximity guidance 
               
             
          
           
               
                 If B = BEX then  ‘Number of lanes do not change before exit 
               
             
          
           
               
                 TARLANE = TAROFF(BEX,EXZ) 
                  ‘TAROFF is provided by static database. It 
               
               
                 is the 
                  lane in the zone that accesses the exit ramp 
               
               
                 Else ‘ Exit is close 
                   
               
               
                  If TAROFF(BEX,EXZ) &gt; 1 
                 ‘Right hand exit 
               
               
                  then if LN(BEX) &gt; LN(B) 
                 Lane add before vehicle exit 
               
               
                   then TARLANE = LN(B) 
                 ‘Vehicle will move to rightmost lane. If barrel 
               
               
                   
                 changes vehicle will move to rightmost lane again 
               
               
                   else TARLANE = 1 
                 ‘Left hand exit 
               
               
                   
               
             
          
         
       
     
         [0094]    Module 3.3 Check Entry Zone Open 
         [0095]    ‘Module receives information on closed entry zones from ALMAMC. If the planned path uses this entry zone, it sends information to the vehicle navigation system requesting a path re-computation. 
         [0096]    If ZE=ε{ZEX(B)} then EN=1 else EN=0 
         [0097]    ‘If EN=1 then planned entry zone is closed. Send signal to vehicle navigation module indicating that a route re-computation is required. 
         [0098]    Module 3.1 Check Exit Open 
         [0099]    Checks to see whether the exit ramp has been closed for any reason. 
         [0100]    Module 3.2 Check Exit Proximity 
         [0101]    Determines whether the vehicle is sufficiently close to the planned exit ramp to warrant guidance to access the ramp. If sufficiently close, guidance to reach the lane servicing the exit ramp is provided. The test distance (Distset) may be set by the operator. 
         [0102]    Module 3.3 Check Entry Zone Open 
         [0103]    Checks to see if entry zone is open 
         [0104]    Module 4 Identify Allowable Target Lanes and Select Guidance Algorithm 
         [0105]    Module 4 provides guidance for vehicles that are not located at a short distance from an exit which is before the end of the barrel. It provides guidance under various conditions that include the presence or absence of lane closure incidents, lane speed and whether or not speed limits are automatically enforced. Below is a representative listing of the pseudocode. 
         [0106]    Module 4 Pseudocode 
         [0107]    Module 4 provides guidance for vehicles that are not located at a short distance from and exit which is before the end of the barrel. 
         [0108]    Module 4.1 Identify Allowable Target Lanes and Select Guidance Algorithm 
         [0000]    
       
         
               
             
               
               
             
               
             
           
               
                   
               
             
             
               
                 ‘Identify allowable target lanes based on no incident 
               
               
                 For L = LSTART(B) to LN 
               
               
                  For Z = ZE to ZU 
               
               
                   If (VOK(B,L) =1) and(LSS(B,L,Z) = A 
               
               
                    then LOTV(B,Z,L) =1 
               
               
                     else LOTV(B,Z,L) = 0 
               
               
                  Next Z 
               
               
                 Next L 
               
               
                 If the vehicle is in the last zone of the barrel and is not exiting here and the first zone of the 
               
               
                 downstream barrel has a right lane drop and the vehicle is in the lane to be dropped the provide 
               
               
                 guidance to move the vehicle. 
               
               
                 If LN(B+1) = LN(B) −1 ‘Lane drop in next barrel 
               
               
                 and ZC = LZ(B) ‘Vehicle is in the last zone 
               
               
                 and ZC&lt;&gt; EXZ ‘Vehicle doesn‘t exit in this zone 
               
               
                 and CURLANE = LN ‘Vehicle is in the right lane 
               
               
                 then TARLANE(B+1,1) = LN(B+1) ‘Moves vehicle to right lane in first zone in next 
               
             
          
           
               
                   
                 barrel 
               
             
          
           
               
                 ‘Select guidance algorithm 
               
               
                 ‘BARNORM is barrel state (normal or incident) as obtained from ALMAMC. If any lane in a 
               
               
                 barrel is not fully open (down arrow), BARNORM(B) = 1. This information is transmitted from 
               
               
                 the ATMAMC to the vehicle. 
               
               
                 If BARNORM(B) = 0 then go to Module 4.3 else go to Module 4.2 
               
               
                   
               
             
          
         
       
     
         [0109]    Module 4.2 Guidance Under Incident Conditions 
         [0000]    
       
         
               
             
               
               
             
               
             
               
               
             
               
             
           
               
                   
               
             
             
               
                 ‘If a lane in a barrel is not fully open and if the vehicle is upstream of the closure point the 
               
               
                 strategy is to provide directions to the vehicle to comply with the lane control signals. 
               
               
                 If LSS(B,Z,CURLANE) =E then LC(B,Z,CURLANE) = E ‘Vehicle must change lane at earliest 
               
             
          
           
               
                   
                 possible time 
               
             
          
           
               
                  else if LSS(B,Z,CURLANE) =D then LC(B,Z,CURLANE) = D Vehicle must change 
               
             
          
           
               
                 lane at  
                 earliest possible time 
               
             
          
           
               
                   else if LSS(B,ZCURLANE,) =A then LC(B,Z,CURLANE) = A ‘Vehicle may 
               
               
                 continue in lane 
               
               
                    else LC(B,Z,CURLANE) = H  ‘vehicle must stop prior to entry into 
               
               
                 Zone Z 
               
               
                 ‘In the absence of lane control indications by the traffic management center, the ATMAMC will 
               
               
                 set LSS(B,Z,CURLANE) = A 
               
               
                   
               
             
          
         
       
     
         [0110]    Module 4.3A Normal Guidance (Speed Stays within Speed Limit) 
         [0000]    
       
         
               
             
               
               
             
               
             
           
               
                   
               
             
             
               
                 ‘Find average speed of lanes in anticipated vehicle route 
               
               
                 For L = LSTART(B) to LN 
               
               
                  For Z = ZE to EXZ 
               
               
                   SUMSPD(Z,L) = 0 
               
               
                   SUMSPD(Z,L) = SUMSPD(Z,L) + SPTMC(B,Z,L) + ‘SPTMC(B,Z,L) from 
               
               
                 ATMAMC 
               
               
                  Next Z 
               
               
                  AVSPD(B,L) = SUMSPD(Z,L)/LN 
               
               
                 Next L 
               
               
                 ‘Identify acceptable lanes above speed limit 
               
               
                 {LNASL} = {}  ‘{LNASL}is the set of lanes above the speed limit {}is an empty set 
               
               
                 For L = LSTART to LN 
               
               
                  LACC(B,L) = 0 
               
               
                  If (LOK(B,L) =1) and (AVSPD(L)) &gt; SL(B,L)) then LACC(B,L) = 1 
               
               
                  {LNASL} = {LNASL} + L ‘L is an element added to {LNASL} 
               
               
                  ‘LACC(B,L) = 0 represents lanes with vehicles below speed limit - use Module 4.4 
               
               
                 Next L 
               
               
                 ‘If there is no acceptable lane above the speed limit, go to Module 4.4 
               
               
                 ACCTEST = 0 
               
               
                 For L = LSTART to LN 
               
               
                 If LACC(B,L) = 1 then ACCTEST = 1 
               
               
                 Next L 
               
             
          
           
               
                 If ACCTEST = 0 then go to Module 4.4 else do  
                 ‘TARLANE is the recommended lane. 
               
               
                   
                 Vehicle may move when convenient 
               
             
          
           
               
                 If OPT = 2 then Go to Module 4.3R else continue 
               
               
                 ‘Find target lane as the allowable lane with the lowest difference between the lane speed and the 
               
               
                 lane speed limit above speed limit 
               
               
                 TARLANE = −1 
               
               
                 For each element E in {NASL} do 
               
               
                    Begin 
               
               
                    SPDTEST = 100 ‘Seed value 
               
               
                    SPDDIF = AVSPD(B,L) − SL(B, E ε NASL) , 
               
               
                    If SPDDIF &lt; SPDTEST then 
               
               
                      Begin 
               
               
                         TARLANE(B) = E ε C NASL 
               
               
                         SPDTEST = SPDDIF 
               
               
                      End ‘If SPDDIF 
               
               
                 End ‘For each 
               
               
                   
               
             
          
         
       
     
         [0111]    Module 4.3R Guidance with Driver Attitude Input 
         [0112]    This module describes the functionality for achieving this when the vehicle may change only one lane at a time. The lateral control system should be provided with a request to change lanes when traffic flow is relatively unconstrained and when the following conditions are satisfied:
       1. The vehicle is following another vehicle and the following vehicle&#39;s driver desires to achieve a faster target speed (Module 4.3R.1).   2. Adjust the vehicle&#39;s speed to a stable following condition (Module 4.3R.2)   3. Determine whether the change to another lane will probably result in the achievement of a speed that is closer to the target speed by a meaningful amount. Select the appropriate lane (Module 4.3R.3)   4. If condition 3 is true, determine whether the target lane is likely to have a gap that is acceptable for vehicle merge purposes. If so, request a lane change (module 4.3R.4).       
 
         [0117]    Module 4.3R.1 Develop Target Speed 
         [0118]    ‘Switch to Module 4.5 if speed limits are automatically enforced 
         [0119]    If AUTOENF(B)=1 then go to Module 4.3A 
         [0120]    else ‘No automatic speed enforcement 
         [0121]    Module 4.3R.1 develops a target speed (TARSPD) as follows: 
         [0000]      TARSPD=TS1(AGR)*WE(B)*RWA*DN 
         [0122]    Values for the variables may be developed as follows: 
         [0123]    TS1(AGR) Baseline Speed Based on Driver Aggressiveness Factor 
         [0124]    TS1 is the base desired speed (desired speed with fair weather, a favorable roadway alignment and daytime visibility conditions), 
         [0125]      FIG. 3  plots data from Ahmed (Ahmed, K. I.,  Modeling Drivers&#39; Acceleration and Lane Changing Behavior,  Doctoral Thesis, MIT, February 1999) showing the fraction of drivers that drive above the speed limit as a function of the driving speed relative to the speed limit. This figure essentially provides the basis for identifying a target speed based on the aggressiveness of the driver. Table 4.3-1 shows representative values for TS1 and was constructed using this data. 
         [0000]    
       
         
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 4.3-1 
               
             
             
               
                   
               
               
                 Driver Aggressiveness Level 
               
             
          
           
               
                   
                 Aggressiveness 
                 Cumulative 
                 TS1(AGR)  
               
               
                 Aggressiveness 
                 Level 
                 probability 
                 MPH above 
               
               
                 Descriptor 
                 (AGR) 
                 Level 
                 Speed Limit 
               
               
                   
               
             
          
           
               
                 Aggressive 
                 1 
                 90% 
                 +7.5 
               
               
                 Mildly Aggressive 
                 2 
                 75% 
                 +5.0 
               
               
                 Average 
                 3 
                 55% 
                 +3.0 
               
               
                 Mildly Conservative 
                 4 
                 25% 
                 0 
               
               
                 Conservative 
                 5 
                 10% 
                 −3.0 
               
               
                   
               
             
          
         
       
     
         [0126]    WE(B) Weather Factor 
         [0127]    This factor describes the fraction of fair weather speed that is usually achieved when inclement weather is encountered. An example of the factors that may be employed is provided in Table 4.3-2 (Chin, S. M., Franzese, O., Green, D. L., and H. L. Hwang,  Temporary Loss of Highway Capacity and Impacts on Performance,  Oak Ridge National Laboratory, November, 2004.) 
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 4.3-2 
               
             
             
               
                   
               
               
                 Reduction in Speed and Capacity 
               
             
          
           
               
                   
                 Highway type 
               
             
          
           
               
                 Weather 
                 Urban freeway 
                 Rural freeway 
                 Urban arterial 
                 Rural arterial 
               
             
          
           
               
                 condition 
                 Capacity 
                 Speed 
                 Capacity 
                 Speed 
                 Capacity 
                 Speed 
                 Capacity 
                 Speed 
               
               
                   
               
             
          
           
               
                 Liht rain 
                   4% 
                 10% 
                   4% 
                 10% 
                  6% 
                 10% 
                  6% 
                 10% 
               
               
                 Heav rain 
                   8% 
                 16% 
                   10% 
                 25% 
                  6% 
                 10% 
                  6% 
                 10% 
               
               
                 Light snow 
                  7.5% 
                 15% 
                  7.5% 
                 15% 
                 11% 
                 13% 
                 11% 
                 13% 
               
               
                 Heavy snow 
                 27.5% 
                 38% 
                 27.5% 
                 38% 
                 18% 
                 25% 
                 18% 
                 25% 
               
               
                 Fog 
                   6% 
                 13% 
                   6% 
                 13% 
                  6% 
                 13% 
                  6% 
                 13% 
               
               
                 Ice 
                 27.5% 
                 38% 
                 27.5% 
                 38% 
                 18% 
                 25% 
                 18% 
                 25% 
               
               
                   
               
             
          
         
       
     
         [0128]    It is not recommended that this factor be applied to short roadway sections, but rather to reflect general conditions in a longer roadway section such as a barrel. 
         [0129]    RWA(B) Roadway Alignment Factor 
         [0130]    This factor provides an adjustment for target speed reduction when design characteristics for major sections of the roadway (such as a barrel) that feature characteristics that are below interstate standards. These characteristics may include lane width below 12 feet, lack of paved shoulders and tighter horizontal alignments. Estimates of the operating speed for roadway sections with substandard alignments are provided by Table 4.3-3 (University of Southern Queensland on line 07/02/13 http://www.usq.edu.au/course/material/SVY2301/CIV2701/Lectures/Lectures%207-%20CIV2701-%20Design%20Factors%20-%20Speed.pdf) 
         [0000]    
       
         
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 4.3-3 
               
             
             
               
                   
               
               
                 Operating Speeds with Substandard Alignment 
               
             
          
           
               
                   
                 Range of 
                   
                 Section 
               
               
                   
                 Radii in 
                 Single Curve 
                 Operating 
               
               
                   
                 Section 
                 Section Radius 
                 Speed  
               
               
                   
                 (m) 
                 (m) 
                 (km/h) 
               
               
                   
                   
               
             
          
           
               
                   
                  45-65 
                 55 
                 50 
               
               
                   
                  50-70 
                 60 
                 52 
               
               
                   
                  55-75 
                 65 
                 54 
               
               
                   
                  60-85 
                 70 
                 56 
               
               
                   
                  70-90 
                 80 
                 58 
               
               
                   
                  75-100 
                 85 
                 60 
               
               
                   
                  80-105 
                 95 
                 62 
               
               
                   
                  85-115  
                 100 
                 64 
               
               
                   
                  90-125  
                 110 
                 66 
               
               
                   
                 100-140 
                 120 
                 68 
               
               
                   
                 105-150 
                 130 
                 71 
               
               
                   
                 110-170 
                 140 
                 73 
               
               
                   
                 120-190 
                 160 
                 75 
               
               
                   
                 130-215 
                 175 
                 77 
               
               
                   
                 145-240 
                 190 
                 79 
               
               
                   
                 160-260 
                 210 
                 82 
               
               
                   
                 180-285 
                 235 
                 84 
               
               
                   
                 200-310 
                 260 
                 86 
               
               
                   
                 225-335 
                 280 
                 89 
               
               
                   
                 245-360 
                 305 
                 91 
               
               
                   
                 270-390 
                 330 
                 93 
               
               
                   
                 295-415 
                 355 
                 96 
               
               
                   
                 320-445 
                 385 
                 98 
               
               
                   
                 350-475 
                 410 
                 100 
               
               
                   
                 370-500 
                 440 
                 103 
               
               
                   
                 400-530 
                 465 
                 105 
               
               
                   
                 425-560 
                 490 
                 106 
               
               
                   
                 450-585 
                 520 
                 107 
               
               
                   
                 480-610 
                 545 
                 108 
               
               
                   
                 500-640 
                 570 
                 109 
               
               
                   
                 530+ 
                 600 
                 110 
               
               
                   
                   
               
             
          
         
       
     
         [0131]    DN Nighttime Factor 
         [0132]    This factor provides for the situation where roadways may experience speed reduction under darkness conditions. 
         [0133]    Module 4.3R.2—Select Lane to Consider for Transfer 
         [0134]    The average distance between freeway lane changes is approximately 2.8 miles (Lee, S. E, Olsen, E. C. B. and W. W. Wierwille, A Comprehensive Examination of Naturalistic lane Changes, USDOT Report No. DOT HS 809702), March 2004). The objective of the module is to identify lane changes that will lengthen this distance (saving fuel, reducing crashes and providing a smoother ride) while still maintaining the driver&#39;s preferences. 
         [0135]    The module identifies candidate lanes in which to merge, compares the current speed with the speed ahead in the candidate lanes and recommends the lane to consider further. Sub-module descriptions are provided below. 
         [0136]    Module 4.3R.2.1 Comparison of Vehicle Speed to Target Speed 
         [0137]    If the current vehicle speed is within an acceptable threshold relative to the target speed no further action is required. Otherwise the Module 4.3R.2 module processes will continue. 
         [0138]    Module 4.3R.2.2 Delay Action 
         [0139]    Vehicle is traveling at an acceptable speed, take no further action for a period equal to T1, then return to Module 4.3R.1. 
         [0140]    Module 4.3R.2.3 Test for Stable Following 
         [0141]    Module 4.3R.2 is based on the assumption that the vehicle is following a preceding vehicle with a speed difference that does not vary by more than a preset threshold. Otherwise the gap relative to the preceding vehicle is changing and following is not stable. It is assumed that the vehicle&#39;s ACC will provide the difference in the vehicle&#39;s speed and the speed of the preceding vehicle (SPPRE). Two tests, at time differences of T2 seconds will be required. Each will be required to show a SPDIF within STTH5 before the remainder of the module is executed. 
         [0142]    If SPPRE(T) and SPPRE(T+T2)&lt;|STTH5| then SF=True else SF=False 
         [0143]    If SF=True then go to Module 4.3R.2.5 else goto Module 4.3R.2.4 
         [0144]    Module 4.3R.2.4 Delay Action 
         [0145]    If following is not stable, the driver or ACC must take action to provide stable following before lane changing criteria can be further tested. 
         [0146]    Module 4.3R.2.5 Number of Look-Ahead Zones 
         [0147]    Zone lengths vary. To provide a basis for examining the region ahead of the vehicle a conversion between the desired look-ahead distance and the number of zones required to achieve this distance must be developed and rounded. This module computes the number of look-ahead zones required to approximately satisfy the desired look-ahead distance DLA. 
         [0148]    ‘Find last look ahead zone (ZLA) based on current zone (Z6). ZLA may temporarily exceed number of zones in barrel (will be corrected later) 
         [0000]      ZLA=ZC+1 
         [0149]    While LAD&lt;DLA do 
         [0150]    Begin 
         [0151]    LAD=LAD+LEN(ZLA+1) 
         [0152]    Next ZLA 
         [0153]    End 
         [0154]    End ‘While 
         [0155]    ‘Select last zone for look-ahead computation 
         [0156]    If ZLA&gt;ZL(B) then LASTZONE(B+1)=ZLA−ZL(B) else LASTZONE(B)=ZLA(B) 
         [0157]    Module 4.3R.2.6 Look-Ahead Speed using Current Zone Speeds 
         [0158]    A length weighed average of zone speeds is computed for the look-ahead distance according to the following expression: 
         [0000]    
       
         
           
             
               Look 
                
               
                   
               
                
               ahead 
                
               
                   
               
                
               speed 
                
               
                   
               
                
               for 
                
               
                   
               
                
               each 
                
               
                   
               
                
               lane 
             
             = 
             
               
                 
                   Σ 
                   
                     Z 
                     + 
                     1 
                   
                   
                     Last 
                      
                     
                         
                     
                      
                     zone 
                   
                 
                  
                 Zone 
                  
                 
                     
                 
                  
                 speed 
                 * 
                 zone 
                  
                 
                     
                 
                  
                 length 
               
               
                 
                   Σ 
                   
                     Z 
                     + 
                     1 
                   
                   
                     Last 
                      
                     
                         
                     
                      
                     zone 
                   
                 
                  
                 
                     
                 
                  
                 Zone 
                  
                 
                     
                 
                  
                 length 
               
             
           
         
       
     
         [0159]    The algorithm is as follows: 
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                   
                 SPLEN =0 
               
               
                   
                   
                 LENSUM =0 
               
               
                   
                   
                 For L = 1 to LN 
               
               
                   
                   
                 For ZZ = Z + 1 to LASTZONE 
               
               
                   
                   
                  SPLEN = SPTMC(B,ZZ,L) * ZLEN(B,ZZ) 
               
               
                   
                   
                  LENSUM = ZLEN(B,ZZ) 
               
               
                   
                   
                 Next ZZ 
               
               
                   
                   
                 ZWAS(L) = SPLEN/LENSUM 
               
               
                   
                   
                 Next L 
               
               
                   
                   
               
             
          
         
       
     
         [0160]    Module 4.3R.2.7 Identify Speed for Adjacent Lanes 
         [0000]    
       
         
               
             
               
               
             
               
               
             
               
             
               
               
             
               
               
             
           
               
                   
               
             
             
               
                 ‘CURLANE obtained from vehicle 
               
               
                 ‘Algorithm is based on no use of shoulders as a travel lane. Must be altered if this is not the 
               
               
                 case. 
               
               
                 If CURLANE =1 then LAL = X else if CURLANE − 1 not an opposite flow lane then LAL = 
               
             
          
           
               
                 CURLANE −1 else LAL = X  
                 ‘Identifies left look-ahead lane 
               
             
          
           
               
                 If LAL ≠ X then SLAL = ZWAS(LAL) 
                 ‘ Speed for left look-ahead lane 
               
             
          
           
               
                 If CURLANE = LN then RAL = X else if CURLANE − 1 not an opposite flow lane then RAL = 
               
             
          
           
               
                 CURLANE + 1 else RAL = X 
                 ‘Identifies right look-ahead lane 
               
             
          
           
               
                 If RAL ≠ X then SRAL = ZWAS(RAL)  
                 ‘ Speed for right look-ahead lane 
               
               
                   
               
             
          
         
       
     
         [0161]    Module 4.3R.2.10 Establish Criteria for Lane Change 
         [0162]    To this point, it has been determined that the vehicle is not close to the desired speed, look-ahead zones have been established and look-ahead speeds have been developed for these zones. This module establishes the criteria for determining whether a lane change is worthwhile. This criteria could be the subject of future research, therefore this module has been established as a placeholder for the results of such research. 
         [0163]    The current criterion is the establishment of a threshold STH4 defined as the speed improvement in look-ahead speeds required to justify the move to an adjacent lane. 
         [0164]    Module 4.3R.2.11 Select Lane for Merge Consideration 
         [0165]    The module tests look-ahead speeds in the current lane and lanes to the left and right of current lane relative to the desired speed. The module selects the highest speed lane that does not exceed the desired speed, provided the speed difference exceeds a threshold STH4. 
         [0000]    
       
         
               
             
           
               
                   
               
             
             
               
                 If (SLAL − ZWAS(L)) &gt; STH4 and SLAL &lt; TARSPD then MLAR = OK else MLAL = NOK 
               
               
                 ‘tests left lane indifference to move and target speed compliance 
               
               
                 If (SLAR − ZWAS(L)) &gt; STH4 and SLAR &lt; TARSPD then MLAL = OK else MLAR = NOK 
               
               
                 ‘tests right lane indifference to move and target speed compliance 
               
               
                 If MLAL ≠ OK and MLAR ≠ OK then go to Module 4.3.1 ‘No lane change 
               
               
                  Else if MLAL = OK and MLAR ≠ OK then MOVELEFT ‘consider left lane for gap 
               
               
                 criteria 
               
               
                   Else if MLAR = OK and MLAL ≠ OK then MOVERIGHT ‘consider right lane 
               
               
                 for gap    criteria 
               
               
                    Else if MLAL = OK and MLAR = OK then ‘select faster lane 
               
               
                    If SLAL &gt; SLAR then MOVELEFFT else MOVERIGHT 
               
               
                 Go to Module 4.3R.2.12 
               
               
                   
               
             
          
         
       
     
         [0166]    Module 4.3R.2.12 Request Move if Gap is Sufficient 
         [0167]    The preceding sub-modules of Module 4.3 have quantified driver preferences and have constrained the adjacent lane change possibilities by various factors. Some of these constraints are oriented to retaining existing traffic flow conditions and motorists&#39; driving habits as developed for conventional vehicles. This assumption was made for the following reasons:
       When market penetration is low, non-conformance with existing traffic patterns will result in modifications to these patterns. While strategies exist that may be acceptable to automated vehicles, they may be discomforting to drivers of conventional vehicles. Initial introductions of this technology should probably avoid these issues.   Strategies that result in roadway capacity changes may have unintended traffic redistribution effects.       
 
         [0170]    Module 4.4 Guidance when Lane Speed is Below the Speed Limit 
         [0000]    
       
         
               
             
               
               
             
               
             
               
               
             
               
             
               
               
             
           
               
                   
               
             
             
               
                 Begin 
               
               
                 ‘Direct vehicle to fastest lane when no lanes above the speed limit are  
               
               
                 available 
               
             
          
           
               
                   
                 DVAR2 = 0 ‘DVAR2 is temporary parameter 
               
             
          
           
               
                 For L = 1 to LN 
               
             
          
           
               
                   
                 If VOK(B,L) = 1 and AVSPD(B,L) &gt; DVAR2 then TARLANE = L 
               
               
                   
                 If AVSPD(B,L) &gt; DVAR2 then DVAR2 = AVSPD(B,L) 
               
             
          
           
               
                 Next L 
               
             
          
           
               
                 End 
                 ‘Module 4.4 
               
               
                   
               
             
          
         
       
     
         [0171]    Module 4.1 Identify Allowable Target Lanes and Select Guidance Algorithm 
         [0172]    Module 4.1 identifies lanes available based on vehicle characteristics, tolling and operator preferences. Based on closure information from the ALMAMC, if lane in the barrel is not fully open, module 4.2 is selected. Module 4.3 is selected in the event of no lane closures 
         [0173]    Module 4.2 Guidance Under Incident Conditions 
         [0174]    If all lanes in the barrel are not fully open (down arrow) the directions provided to the vehicle emulate the lane control signals. 
         [0175]    Module 4.3A Normal Guidance if Speed Limits are not Automatically Enforced 
         [0176]    The module switches to Module 5 if there is automatic speed enforcement. The module determines which lanes have speeds above the speed limit and directs the vehicle to the lane with the lowest speed above the speed limit. When the control speed is set to the speed limit in Module 5, this will result in the least disruption to traffic in the barrel. 
         [0177]    Module 4.3R Guidance with Driver Attitudinal Input 
         [0178]    This module provides guidance when driver attitude input is considered along with roadway alignment and weather factors. 
         [0179]    Module 4.4 Guidance when Lane Speed is Below the Speed Limit 
         [0180]    When all lanes are fully open but the speed in all lanes is below the speed limit, the vehicle is directed to the fastest lane. 
         [0181]    Module 5 Lane Speed Guidance 
         [0182]    Used in conjunction with Module 4A, this module sets a target speed for the target lane. The target speed is the speed limit or lower. 
         [0000]    
       
         
               
             
               
               
             
               
               
             
               
               
             
           
               
                   
               
             
             
               
                 ‘Compare current zone speed for target lane with current speed limit 
               
               
                 If (SPTMC(B,Z,L) = −1 then TARSPD(B,Z,L) = −1 ‘Speed data not accurate, can&#39;t set target 
               
               
                 speed 
               
               
                 If SPTCM(B,Z,L) = −1 then Go to [A]   ‘Eliminates next statement if speed is not accurate 
               
               
                 If SPTMC(B,Z,L) &gt; SL(B,Z,L) then TARSPD(B,Z,L) = SL(B,Z,L)   ‘sets to speed limit 
               
             
          
           
               
                   
                 else TARSPD(B,Z,L) = SPTMC(B,Z,L) + SPPUSH ‘sets to current lane speed with 
               
             
          
           
               
                   
                 push to close gaps 
               
             
          
           
               
                 [A] 
                 ‘branch to bypass previous statement when necessary 
               
               
                   
               
             
          
         
       
     
         [0183]    Module 5 Speed Guidance 
         [0184]    For the target lane selected in Module 4, if the if the current zone lane speed for the targeted lane exceeds the speed limit for that lane, the module targets the vehicle speed as the speed limit. If the lane speed is lower than the speed limit, the targeted speed is set to the current speed plus an increment. The increment is intended to push the vehicles speed into a vehicle following condition to avoid unnecessary gaps being developed in the traffic stream. 
       Appendix A 
     Symbols and Abbreviations 
       [0185]    Refer to process descriptions for index referencing
       A—Type of toll tag (e.g. EZ Pass)   ACCTEST—Temporary parameter   ACT—Currently relevant barrel activation limits   AGR—Driver aggressiveness level   AUTOENF—Automatic enforcement of speed limit in barrel   AVL—Average vehicle length   AVSPD—Average lane speed in barrel   B—Barrel number—a barrel is a homogeneous section of roadway (number and static or time of day use of lanes remains constant). Barrels may be separated by physical or functional separation. Barrel number must include a reference direction (N or E). E.g. E4   BARNORM—Barrel incident status (0 if normal, 1 if abnormal)   BC—Downstream barrel when vehicle path continues past current barrel   BEX—Barrel containing exit zone   CURLANE—Lane in which vehicle is currently located   DI—Test zone width   Distset—Distance to begin search for exit location prior to end of barrel   DLA—Look-ahead distance threshold   DN—Nighttime factor   DTE—distance to exit   DVAR—Temporary parameter   E—Element in NASL   EC—Set of in barrel that access closed entry ramps   EN—Indicated entry zone state   EXC—Required exit closed (true, false)   EXL—Lane to access exit ramp   EXZ(BEX)—Zone vehicle exits from path (Last zone in path that vehicle traverses prior to exit from barrel)   INCZONE—Set of closed lane(s) in this zone   INTESTZONE—Vehicle in test zone   ITS—Intelligent Transportation Systems   L—Lane ID. Relative to reference direction for barrel even when major or complete flow is in opposite direction. Designate full left shoulder as L=0 (denote as X if shoulder doesn&#39;t exist, designate full right shoulder as RS if present. The leftmost normal travel lane is designated as L=1. With opposite flow lanes, add the designator R after the lane ID   LA—Lanes available in entire barrel for vehicle   LACC—Lane with speed above speed limit. L is the ID number of the lane with speed above the speed limit that is acceptable (LACC(B,L)=1) including the other vehicle constraints. LACC(B,L)=0 is below the speed limit   LAD—Look-ahead distance   LAL—Left look-ahead lane   LASTZONE—Last zone for look-ahead averaging   Lat—Latitude   LC—Lane commands. Define as follows
           A—Left or right merge or straight permitted   B—Prohibited merge to left   C—Prohibited merge to right   D—Required merge to left   E—Required merge to right   F—Required merge to left or right   G—Vehicle not qualified to use lane   H—Stop vehicle   J—Notify vehicle that lane guidance is terminated   K—Straight permitted   
           LEN—Look-ahead distance   LFD—Lane flow direction   LN—Number of lanes in barrel   LNASL—Set of lanes in barrel with speeds above speed limit   LOK—Certain static lane closure requirements   Long—Longitude   LOTV—Lanes open to vehicle (0=No, 1=Yes)   LSS—Lane control command from ALMAMC
           A—Straight permitted   D—Move to left   E—Move to right   F—Lane closed   J—No guidance provided   
           LSTART—Dynamic lane index (0 indicates open running shoulder, 1 indicates restricted use)   LTEMP—Intermediate parameter   LTYPE—Lane type (LTYPE=HOT for hot lanes else LTYPE=C)   LVR—Lane vehicle requirements. May be dynamic. Define as follows:
           A—Passenger cars only   B—Buses only   C—Trucks only   D—No trucks   E—Buses and trucks only   F—No restrictions   
           LZ—Last zone in barrel   MLAL—Identifies whether OK to move left   MLAR—Identifies whether OK to move right   MOVELEFT—Recommendation to vehicle controls to move left   MOVERIGHT—Recommendation to vehicle controls to move right   NEXTZONE—The subsequent zone in the path set   OC—Overheight clearance   ON—Number of vehicle occupants required for of HOV lane or toll free on HOT lane. This is provided in the static database as a function of time-of-day   OPT—Driver selected option for selection of algorithm incorporating motorist preferences
           OPT=1—No incorporation of motorist preferences   OPT=2—Incorporation of motorist preferences   
           OWC—Overweight clearance   P—Path in barrel   PELAT—Latitude of planned exit   PELON—Longitude of planned exit   RAL—Right look-ahead lane   RWA—Roadway alignment factor   PO—Number of vehicle occupants (data from ODE)   SF—Stable following condition   SL—Speed limit   SLAL—Speed for left look-ahead lane   SLAR—Speed for right look-ahead lane   SPDDIF—Difference between average lane speed and speed limit   SPDTEST—Temporary parameter   SPPRE—Difference in vehicle&#39;s speed and speed of preceding vehicle   SPPUSH—Incremental speed   SPTMC—Zone speed from ATMAMC   STH4—Speed improvement in look-ahead speeds required to justify the move to an adjacent lane   STTH5—Threshold for vehicle following test   SUMSPD—Sum of zone speeds (intermediate computation)   T2—Time difference for stable car following test   TARLANE—Target lane   TAROFF—Lane next to exit ramp or lane for connector ramp (static database)   TARSPD—Target speed for lane in zone, −1 indicates that data is not available   TRA—Toll rate by lane   TS1—Miles per hour above speed limit   TTA—Set of types of toll tags available to vehicle
           A—E-ZPass   
           TTC—Vehicle cleared for toll tag use   TTL—Toll tag requirement for lane (Y/N)   TTU—Does driver want to use toll tag for trip (Y/N)   VC—Vehicle class
           A—Passenger car   B—Bus   C—Truck   
           VH—Vehicle height—Ft   VHL—Vehicle height limit   VLAT—Vehicle latitude (from GPS)   VLON—Vehicle longitude (from GPS)   VOK—Vehicle &amp; toll characteristics OK for lane   VS—Vehicle speed   VW—Vehicle weight—Wt   VWL—Vehicle weight limit   WE—Weather factor   Z—Zone ID in barrel for which computation is to be performed   ZC—Zone that vehicle is currently in   ZE—Entry zone to path   ZEX—Set of closed entry zones in barrel   ZL—Last zone in barrel   ZLA—Last look-ahead zone   ZLEN—Zone length   ZP—Zone path (set)   ZU—Number of zones in path   ZWAS—Look ahead speed for each lane