:SIGNAL94 Ver 1.23 27AUG98
>TEAPAC Interface Ver 3.03 Changes Made.
A unique new licensing technique has been implemented in the Ver 3.03 Interface which will allow users to download free updates of TEAPAC programs from the Internet, without the need for pre-arranged passwords or download codes. When the demos found at the Strong Concepts homepage are run on the users system, the licensed Usage Level will be automatically enabled. The licensing also allows either Win16 or Win32 operation from the same license, both of which will be available along with the DOS-based version of each program on CD-ROM distribution.
The SaveAs function will now report that a selected file name already exists, asking if it should be overwritten. Also, the brief window giving feedback about the successful Save or SaveAs function has been lengthened from 3 to 5 seconds. The default location of user data files has been changed from '.\' to the installed TEAPAC folder location (usually C:\TEAPAC) for more consistency with normal Windows operations.
A new option for DOS TEAPAC programs in line five of the .CFG file allows the entry of 'HPLJx' to indicate that the printer attached to 'LPTx' is a Hewlett Packard LaserJet compatible printer. This complements the 'LPTx' option added in the Ver 3.01 interface so that required HPLJ printer codes are sent to the printer for each page, and are no longer required as a separate effort by the user. This is most significant in shared and networked printer environments. Note that when LPTx is used, the F6 key functions only when the printer is attached to LPT1 (or PRN).
When the '&' character is used in the Manual Mode of a Windows program, the next prompt received has been modified to include the '&' character to indicate that the entry to be made is a continuation of the previous entry, not a new command entry. This now behaves similarly to the DOS Manual Mode, in this regard.
:SIGNAL94 Ver 1.22 05MAR98
>TEAPAC Interface Ver 3.02 Changes Made.
Various support files which are used by the program are now closed after their use so that other TEAPAC applications which are running concurrently on the same or other networked computers have less opportunity to conflict with the use of these files.
In Win32 versions, the vertical scroll button of the Output window can now be clicked and dragged to scroll through the output from top to bottom. Previously, this button's position could only be clicked to change the view of the output.
In Win32 versions, the File-Open and File-SaveAs dialog boxes now display the last file used in the FileName field, as well as the dialog's caption, providing an easier way to retrieve and save files with variations of previous file names.
:SIGNAL94 Ver 1.21 17DEC97
>Minor Adjustments to Accommodate Unusual Conditions.
Under WindowsNT and sometimes other Windows platforms, certain conditions could produce division by zero errors in the Capacity Analysis Worksheet which could crash earlier versions of WinSIGNAL94. These conditions would not produce erroneous results when NT or any other platform did not detect the problem, so no prior SIGNAL94 results need to be checked. For example, when a protected-permitted left turn is made without an exclusive left turn lane, the HCM methodology might have trouble determining a critical movement involving that left turn, thus resulting in division by zero. This condition has been fixed.
Another condition which may have been encountered was the apparent need for a Help file which did not appear to exist. For example, pressing F2 within various dialogs might produce such an error. This error message was produced in error, and has been removed.
>TEAPAC Interface Ver 3.01 Changes Made.
Minor changes which are now incorporated into Ver 3.01 of the standard TEAPAC Interface have been implemented in SIGNAL94. These include the following changes and enhancements:
In Windows versions of SIGNAL94, data files can be dragged from other applications like Windows Explorer or File Manager and dropped on the main window of a running copy of WinSIGNAL94. This is equivalent to using the File-Open dialog of the program for the dragged file.
The maximum amount of output which can be viewed in the Results window of WinSIGNAL94 has been increased to 64,000 characters from the previous 20,000 characters to allow larger multiple-scenario analyses to be observed directly within the program.
When error messages are displayed during file open processes in WinSIGNAL94, the messages now more clearly depict the name of the file for which the errors have been generated.
The maximum size of file names (including the path defined in the .CFG file) has been increased to 64 characters. Under the Win32 version of WinSIGNAL94 the defined paths may now also have embedded blanks, although this is not recommended. Actual file names should still be 11 characters or less (including Win32 versions), and any embedded blanks for a SaveAs name will be replaced by the underscore character, since embedded blanks are still not permitted in file names. Note that if SAVEd files are renamed to include more than 11 characters or embedded blanks, the shortened (8.3) file name displayed by the DIR command of the Command Prompt may still be used, even in the Win32 version of the program.
In the DOS version of SIGNAL94, a new entry has been added to the end of the SIGNAL94.CFG file which can be used to define the destination of printed output. The default has been changed from the "PRN" value previously used to "LPT1". This can be changed to any valid DOS printer device name. A file name may also be used for this entry to direct all "printed" output to an ASCII file (in lieu of the IODEVICES option which requires use of the Manual Mode).
New versions of the TEAPAC.BAT and WinTEAPAC shell programs (Ver 3.01) have also been produced, primarily to handle the new CORSIM program. CORSIM is now the default option of each shell. WinTEAPAC also allows running the DOS version (NETSIM) by first selecting a DOS check box. The DOS check box can also be used to over-ride the presence of a Windows version of a TEAPAC program such as SIGNAL94, PREPASSR, PRETRANSYT or PRENETSIM by forcing the running of the DOS version instead. The normal mode is now to search for and run the Windows version of any TEAPAC program before a DOS version is attempted. The newest version of WinTEAPAC also fixes a problem sometimes encountered on WinNT (and some Win95 systems) when trying to run DOS programs from the WinTEAPAC shell. Improved error message have been created as well, and long path names are also supported, although not encouraged, in the WTEAPAC.CFG file.
:SIGNAL94 Ver 1.20 25DEC96
>First Release of Windows Version of SIGNAL94.
This version of SIGNAL94 marks the first release of a Windows version of SIGNAL94, featuring the new Visual Mode of operation. SIGNAL94 for Windows is available in a 16-bit version which runs on Windows 3.x and Windows 95, as well as a 32-bit version which runs on Windows 95 and Windows NT.
>One-lane Approach Methodology Changed.
Previous versions of SIGNAL94 were making an unnecessary (and inappropriate) check for a single-lane approach condition when evaluating the permitted left turn model. This check was based on the same check made in the 1985 HCM, and thus in SIGNAL85, but was removed in the 1994 update to the HCM. This was previously known as Case 7 in Table 9-12. This erroneous check may have caused overly conservative results for these conditions in previous versions of SIGNAL94.
:SIGNAL94 V1 L1.4 17JUN95
>New Limit on Opposing Queue Ratio Used for Permitted Left Turns.
A new limit on the opposing queue ratio for permitted left turns has been implemented which prevents erroneous results for extreme cases. In cases when an opposing movement has a very high green time and very favorable progression, the computation for the opposing queue ratio can become negative. This is not a valid result, and will create negative green time calculations in subsequent calculations. Imposing a lower limit of zero on the opposing queue ratio calculation eliminates this problem. This limit is not currently in the Highway Capacity Manual, but will more than likely appear as an addendum at a later date.
:SIGNAL94 V1 L1.3 02JUN95
>Export to HCS-Signals Release 2.4 Now Directly Supported.
Now that HCS-SIGNALS Release 2.4 is available, SIGNAL94's EXPORT function uses the new data file format which this version of HCS uses. The main difference from the user's perspective is that GREENTIMES and YELLOWTIMES from SIGNAL94 no longer need to be rounded to the nearest integer value, so more precise comparisons between SIGNAL94 and HCS can be achieved. In fact, with this change there are now virtually no known differences between the two analyses except for insignificant rounding adjustments. Another improvement is the addition of PVG-entry support as an alternative to ARRIVALTYPE. This has always been supported in SIGNAL85 and SIGNAL94, but now these inputs are exported to HCS as well when used. A change to the PARKINGVOLS export has also been made to better represent parking conditions which include left side parking (which HCS does not explicitly support).
It is important to note that SIGNAL94 exports will now not be able to be read by earlier versions of HCS Release 2 since the new HCS file format is not downwards compatible. This is not expected to be an issue in most cases, but if it is required, an earlier version of SIGNAL94 or SIGNAL85 should be used. Release 1 versions of HCS are still supported by SIGNAL94 by using the .SIG extension, and this can be used as an alternate for inputting to earlier versions of HCS Release 2.
>More Flags in Output Used to Identify Oversaturated Conditions.
Additional flags in the outputs of the Level of Service Worksheet and the Capacity Analysis Summary have been added to alert the user of conditions where v/c values have exceeded allowable limits for the accurate computation of delay values. These flags are indicated with the "@ " character next to delay values and the additional note to "expect more delay due to extreme v/c's (see EVALUATE)". As before, the delay calculations are made using the limiting value of v/c so that the user gets a numeric result which can be perceived as a lower bound of the expected delay. We believe this is more helpful that just outputting "*" instead of any delay value at all. The reference to EVALUATE is to further induce the user to view the EVALUATE results which are much more appropriate calculations for oversaturated conditions, since they use a formula similar to that used in TRANSYT-7F.
>Time Period for Cumulative Calculations Reduced from 60 Minutes to 15.
For better consistency with the intent of the Highway Capacity Manual, the analysis time period for the cumulative calculations of the EVALUATE report has been set to 15 minutes rather than the previous value of 60 minutes. The Manual states that the conditions being analyzed by the HCM procedures are expected to exist for a period of at least 15 minutes, and it thus follows that these cumulative values should be for the same amount of time. The values affected include Average Delay (when oversaturated), Total Delay, Number of Stops, Maximum Queue (when oversaturated), Fuel Consumption and CO Emissions. Units of output have been adjusted accordingly. If the analysis period is actually longer than the 15 minute period used, these results should be adjusted to reflect the actual time period.
>Division by Zero Error Trapped in Protected+Permitted Delay Calculations.
Certain rare situations may lead to division by zero problems in the protected+permitted supplemental delay calculations. These conditions have been trapped and now deliver appropriate results rather than aborting out of the SIGNAL94 program.
:SIGNAL94 V1 L1.2 08APR95
>Improved Optimization Method Produces Better Optimums than Before.
Two changes have been made to SIGNAL94's optimization techniques which will result in better optimizations in many cases. The first change finds a better answer in a single DESIGN optimization pass whereas before users may have noticed a slight improvement in the optimization if it was re-DESIGNed after an initial DESIGN 1 optimization. This result is now achieved in a single pass and any subsequent DESIGN 1 optimizations will yield the same results.
Another change has been made to limit the occasions where SIGNAL94 will produce an optimal phasing which has zero time assigned to any given phases. In many of these cases, a simpler phasing, if allowed, will now be identified as optimal which simply omits the zero phase rather than setting its time to zero. This condition was frequently observed, for example, when a right turn was a critical movement in a phasing which produced zero time for an overlap phase.
With these two changes, it is recommended that any optimizations done with previous versions of SIGNAL94 be re-executed to verify the slightly better optimization results.
>Modifications Made to Progression Factor Inputs and Calculations.
Several changes have been made to the inputs and calculations related to progression factors which may in certain cases result in considerably different results than before.
The g/C value used in the progression factor (PF) equation is now limited to a value of 0.999 or less to avoid division by zero errors which can occur, particularly in highly saturated circumstances. This could have occurred with either the ANALYZE or DESIGN commands where SIGNAL94 attempts to determine the g/C requirements to operate a given movement at a certain level of service. The proportion arrival on green (PVG) calculation has also been limited to its theoretical maximum of 1.0 in supporting calculations -- this could change results when a high arrival type or platoon ratio was used in conjunction with a large g/C value. In conjunction with this change, platoon ratios as high as 300% are now allowed on input and the help line for ARRIVALTYPES now indicates the ability to enter the platoon ratio or PVG in place of the arrival type.
Under certain conditions, an improper selection criteria may have been applied in the top half of Table 9-13 of the HCM which determines where the Delay Factor DF should be obtained. Now, any time any movements at the intersection have an arrival type other than 3 the signal is deemed coordinated and the right-hand column is used. The row selected is based on the actuated status of the specific movement under consideration.
In light of these changes and the improved optimization described above, re-runs of all SIGNAL94 runs made with previous versions are suggested.
>New Maximum Queue Calculations for Protected+Permitted Left Turns.
Due to the new procedures for calculating delay for protected+permitted left turns, a change has been made in how queues are calculated for these movements. The Supplemental Worksheet for Delay includes queue calculations which are consistent with the 90% maximum queues calculated for other movements in SIGNAL94, but which take into account the irregular shape of the queue accumulation graph as depicted in Figure 9-12 of the HCM. These queue calculations have been substituted into the equations for queues shown in Appendix C of the SIGNAL94 manual to obtain a better estimate of queue for protected+permitted left turns. These values will be generally less than those computed previously.
>New Warning Message for Combined Use of Actuations and Coordination.
Several users of previous versions of SIGNAL94 have stumbled over what is apparently a less-than-fully-understood aspect of the 1994 HCM. This is that if a signal has a coordinated movement on any approach and is therefore declared a coordinated intersection in Table 9-13 of the HCM, any improvement effects of actuations at the intersection are lost. This is because the "background cycle" at the coordinated signal effectively eliminates the signal's ability to by fully responsive to actuated demands as compared to an uncoordinated condition. This is fully documented in the text supporting Table 9-13. However, if a user inputs an arrival type other than 3 in addition to actuated control for a given movement, this suggests the user's expectation for some type of benefit to accrue from either or both of these conditions, when in fact none will occur. To avoid this misconception, a new warning message has been added that identifies this condition and warns the user of the pending result. The proper input is to either have an ACTUATION input OR an ARRIVALTYPE other than 3 for a given movement, but not both. A particular case of this problem is where a "fully-actuated" signal is coordinated and the user is inclined to set ACTUATIONS to YES for all movements. Technically, however, the proper method of input to the HCM method is to declare the coordinated movements as non-actuated and therefore enter NO for ACTUATIONS for any of these movements. Hopefully this new warning message will help avoid this potential input error. The warning can be turned off with the OUTPUT command, like other such warnings.
>Minor Changes to Output Reports.
The total g/C used for protected+permitted phasings is now shown in the Capacity Analysis and Level-of-Service Worksheets. Although not explicitly a part of these worksheets, it was felt that this information could be useful and appropriate in these outputs. A small glitch in the display of arrivaltypes has also been fixed, as well as a proper display of the sequence code when the optimal sequence is not selected, both in the Input Worksheet. Lastly, all previous calculations for the Supplemental Delay Worksheet are now zeroed out so they do not appear in subsequent worksheets. None of these changes have any impact on the results calculated.
:SIGNAL94 V1 L1.1 20MAR95
>Division by Zero Errors Prevented for Certain Left Turn Conditions.
A condition has been detected in the permitted left turn equations of Figure 9-18 of the HCM which can produce unexpected division by zero errors in rare but possible circumstances. This condition has now been trapped to avoid the error and a proper result is delivered for the left turn factor.
>Improved Response to Full-Actuated, Coordinated Signal Condition.
According to Table 9-13 of the HCM, a user should not enter a condition which depicts a fully-actuated signal which also has coordinated approaches. Such a condition should be entered as a semi-actuated signal. This is because the benefits of coordination and actuation are intended to be mutually exclusive, thus the coordinated phase should be entered as non-actuated so it can get the benefits of the coordination. This condition was not coded this way in SIGNAL94, resulting in an obvious incorrect result using a DF of -1 when a fully-actuated signal had an arrival type other than 3. The proper solution to this condition is still to enter NO for the ACTUATIONS of the coordinated movement, but a change has been made in SIGNAL94 that now processes the data as specified -- that is, all phases of a fully-actuated signal will get the DF of 0.85, regardless of the arrival type used, rather than the -1 value used before. The correct input should still be used, however (NO for the ACTUATIONS entry of the coordinated movements) if the proper progression factor is to be determined for that movement.
:SIGNAL94 V1 L1.0 19DEC94
>First Version of SIGNAL94 Hits the Street.
SIGNAL94 is the first piece of software available which implements the procedures of Chapter 9 of the 1994 update to the 1985 Highway Capacity Manual. Over two years in the making and based on its popular predecessor, SIGNAL85, SIGNAL94 was used by the TRB Capacity Committee to help fine tune the new 1994 methods, and particularly in validating the worked sample problems which appear in the publication. Going one major step further than the procedures of Chapter 9, SIGNAL94 also optimizes the phasings and timings of an intersection to produce the best possible capacity analysis, like SIGNAL85 has done for the last 10 years.
>Special Notes for Prior Users of SIGNAL85.
For prior users of SIGNAL85, a special set of notes have been prepared to discuss some of the important differences between using SIGNAL85 and SIGNAL94, as well as how best to use SIGNAL85 data files with SIGNAL94. These notes appear in Appendix C of the new SIGNAL94 manual, and are highly recommended for prior users of SIGNAL85 before using SIGNAL94.
this page last updated October 01, 2005