PC-ALAS User's Guide for Version 2.4 (September 1996)
Prepared by
Iowa Department of Transportation
Engineering Division
Office of Transportation Safety
(515) 239-1668
Table of Contents
List of Figures
List of Tables
Introduction
Accident Database
Program Setup
Types of PC-ALAS Locations
1. Link-Node Locations
2. Milepoint/Milepost Locations
Types of PC-ALAS Requests
1. Node Requests
2. Intersection or Interchange
Requests
3. Link Requests
4. Node String Requests
(Multiple Adjacent nodes)
5. Primary Route Milepoint
Requests
6. Primary Route Milepost
Requests
7. Beat Requests (a user defined
geographic area)
8. Jurisdiction Requests
(by city, county, or state)
Notes for PC-ALAS version 1.0 users
1. Starting the program
2. The desktop
3. Help utility
4. Running a locational search
5. County summaries
6. Selecting accidents by accident characteristics
7. Engineering and law enforcement
reports
8. Ranking reports
9. Specialty reports
10. Special features
Miscellaneous
1. Third party users
2. Reporting a program error
3. Making suggestions for
program improvement
Troubleshooting
Extra help and information
Appendices
A. Troubleshooting
B. Error Messages
C. Obtaining Node Maps and Traffic
Flow Maps
D. Selection Criteria for Accident
Isolation in PC-ALAS
E. Selection Criteria for Accident
Isolation in PC-ALAS
List of Figures 
List of Tables
Introduction
The Office of Transportation Safety at the Iowa Department of Transportation has been developing an easy-to-use, yet powerful traffic accident records system for the past several years. The program, known as PC-ALAS, was developed with both the needs of the state as well as the needs of local enforcement and engineering in minde.
PC-ALAS is available to district and local offices of the DOT as well as smaller government agencies. This reduces both the demand on the Office of Transportation Safety to fill data requests and the time required for a local entity to have access to tha t same information.
PC-ALAS provides a flexible accident query and reporting system. Accident histories can be queried by a variety of location types:
1. a single point (bridge, railroad crossing)
2. an intersection
3. a stretch of road
4. a geographic area
5. an entire jurisdiction
Once the accidents for a location have been selected, it is possible to further reduce the data set by selecting ranges of values found within the accident records.
Example: Pedestrian accidents for an entire city
could be isolated.
The number of search criteria is essentially unlimited.
- All accidents
- where drivers between 16 and 25 years of age
- ran a stop sign
- with a reported BAC greater than 0.08
- where an injured passenger
- was not wearing a seat belt
- etc.
Example:
While this is an unlikely combination of criteria (only a couple of accidents, if any, would qualify), it makes the point for the flexibility of the search criteria.
The beat is another powerful PC-ALAS tool. Using this feature, it is possible to define an entire area for repeated analysis.
Example:
A city's police department could create beats for special areas of enforcement (a downtown district, a college campus, etc.). Once a beat is created, you can save and recall the beat information for various studies involving that particular geographic ar ea.
This feature is excellent for "selective enforcement" as well as "problem identification".
Upon completion of the accident selection phase, several reporting options are available for either enforcement or engineering applications.
Accident Database
The Iowa accident database is compiled from accidents reported by:
1. investigating officers
2. drivers
All accidents occurring on public road systems in the State of Iowa that result in a fatality, a personal injury, or at least $500 property damage are included in the PC-ALAS database. Any personal information (name of driver, names of injured persons, e tc.) related to the involved parties has been removed.
Program Setup
1. Hardware configuration
- the beginning and ending years of accident data
available to PC-ALAS
Example: 89 to 93 (would indicate 1989 to 1993)
- the disk drive on which to find the PC-ALAS programs
and data
Example: C: (would indicate the C: drive)
- the beginning year for the summary .hyp files
Example: 85 (would indicate 1985)
- the maximum number of cases that can be processed
with selection criteria
Example: 50,000 (would indicate 50,000 cases)
PC-ALAS has the capability of running on any PC compatible machine with MS-DOS, PC-DOS, or the equivalent. The type of monitor, installed disk drives, and type of printer are a few differences that may exist from one computer to another. Through a progr am called SETUP.exe, PC-ALAS can be configured to run under the above system variables.
The SETUP.exe program allows the user to specify certain options. Each of these options will "pop up" in a dialog box and ask you to type:
The SETUP.exe program produces a file called PCALAS.sys that should reside on the root directory of the C: disk drive (C:\). All settings are explained in the execution of the SETUP.exe program.
2. Initial installation
- each of the diskettes is inserted in the order
in which it is numbered
- the first diskette is installed before any other
program diskette
In most cases PC-ALAS installation is as easy as inserting a diskette and typing:
A:\INSTALL A: C:
Normally,
A: is the source drive of the installation diskette
and
C: is the target drive on which PC-ALAS is to reside.
The first diskette received with the PC-ALAS package includes a batch file called:
INSTALL.bat
This program is used in conjunction with other programs to install:
the entire System and
Data
onto the local hard disk drive. If multiple diskettes are required for installation, it is important that:
For the first diskette, follow this procedure:
1. Insert the diskette in the floppy disk drive
2. Type A:\INSTALL A: C:
3. Press the [RETURN] or [ENTER] key
4. Answer any questions that the installation program
asks.
3. Program and data updates
After the completion of each calendar year's accident data, each remote user will receive a diskette with the new year's accident data. In addition to the new data, any program upgrades since the last update will also be included.
Types of PC-ALAS
Locations
One of the frequently used abilities of PC-ALAS is its ability to retrieve the accident data for a specific location. In the system, there are several ways of defining a location. Careful considerations should be made when preparing to request data from the system. Following is a discussion of the different ways in which the location information is stored within Iowa's accident database.
1. Link-Node Locations
All accidents are coded to the location at which they occurred through the Link-Node system. The Link-Node system works from maps that have numbers assigned to all intersections, bridges, railroad crossings, etc. (For more information on the Link-Node s ystem and how node numbers are assigned, see Appendix A.) Iowa DOT's Office of Transportation Inventory produces node maps for all cities and counties.
Accidents that occur at a specific node number are assigned to that number. If an accident occurs between two nodes (mid-block), it is coded to both nodes on either side to form a link. In the case of link, there is also a distance in hundredths of a mi le from the first node to the second node.
Accidents that occur in a link but are considered to be intersection related (generally within 100 feet), are coded to the link in which they occurred and to the intersection. Complex intersections and interchanges contain several individual nodes and al so possess a unique intersection identifier.
2. Milepoint/Milepost Locations
In addition to the Link-Node locating scheme, PC-ALAS also uses milepoints and mileposts for locating accidents on the primary road system. This method uses the original link-node assignments to isolate equivalent milepoint and milepost values for all ac cidents that occur on the primary road system. This allows the user to simply supply a beginning and ending point on a specific route to run a section of road.
The milepoint/milepost locations are found by interfacing the link-node location with DOT's roadway inventory files. Since a particular route can change from year to year (cince route mileage and route numbering might fluctuate), care should be taken whe n running a request. A node string, however, should remain unchanged, and can be used for circumstances in which a route change has occurred.
Types of PC-ALAS
Location Requests
Using both milepoints/mileposts and the Link-Node system to store an accident's location, PC-ALAS has access to data through the following eight primary methods:
- Node Requests
- Intersection or Interchange
Requests
- Link Requests
- Node String Requests (Multiple
Adjacent nodes)
- Primary Route Milepoint
Requests
- Primary Route Milepost
Requests
- Beat Requests (a user defined
geographic area)
- Jurisdiction Requests
(by city, county, or state)
Descriptions of each of the several ways that PC-ALAS can retrieve accident data for a specific location or jurisdiction are discussed below. Prior to running a request with the system, it is important that the user understand the fundamental differences between each type of request.
1. Node Requests
- assigned to interchanges and other Multiple
Node Intersections
- The first two digits of the Node number correspond to the county in which the node is located. These two digits have been taken care of in PC-ALAS by allowing the user to enter the county number only once and then enter the last six digits in the Nod e entry field(s).
- The third digit represents the relationship of the township with other townships increasing from South to North.
- The fourth digit represents the relationship of the township with other townships increasing from West to East.
- The fifth and sixth digits correspond to the node's North-South location within the identified township. These digits increase by one for every sixteenth of a mile traveled from the South township line towards the North.
- The seventh and eighth digits are the same as the fifth and sixth digits, with the exception that they signal the node's East-West position, increasing from West to East.
- County
- Time period
- Last six digits of the eight digit Node number
- For summarizing
- For further limiting (using a criteria search)
A node number is an 8 digit number representing a specific location on a roadway.
For example: the intersection of Main Street and First Avenue
would have a specific Node number assigned to it. Any accidents that occurred at that intersection would also be assigned to that number. There are ten roadway elements that are assigned Node numbers:
1. All Intersections (except alleys)
2. Ramp Terminals
3. Railroad Crossings
4. Grade Separation Structures
5. Bridges
6. Road Ends
7. 90 degree Turns (when each leg is at least 1/4
mile long)
8. County Lines
9. Major Signalized Commercial Entrances
10. Complex Intersection Identifier Nodes
Each digit in the eight digit Node number has a certain significance:
When implementing a Node search, the user is required to enter:
With this information, PC-ALAS searches the accident database and stores these accidents in a file:
Node searches only return accidents that occur at that roadway element.
For example: searching for the accidents that occur at a Node number assigned to a bridge will only give you the accidents that have actually occurred at the bridge.
Note: For accidents that occur in-between roadway elements, use the Link search.
2. Intersection or Interchange
Requests
Intersection requests are quite valuable when studying simple intersections as well as complex interchanges. The Intersection request for a Single Node intersection returns the accidents that occur at the Node, as well as intersection related accidents a djacent to the Node.
In complex interchanges, the six digit interchange identifier can be used to return all accidents occurring at the Nodes or within the Links that comprise the complex intersection.
The entry of an Intersection request is essentially the same as for a Node request.
3. Link Requests
A Link describes the area of road between two adjacent Nodes. The Link request can be used to retrieve all accidents that occurred within a Link, but will not include the accidents that occurred at the end points of the Links.
For Link requests, two fields will be below the time period and county information. To define the location, enter the two nodes on each side of the desired Link. If the accidents at the end points are desired, use a two node string search.
To use this request, it is important that there are not any Nodes between the first and second entered.
If there are multiple Nodes in the road section, use a Node string request.
4. Node String Requests (Multiple
Adjacent nodes)
- the county
- the time period
- the various Nodes that are located in the String
A Node String request is very useful when studying a long stretch of road that is not a primary route. Running a Node String request requires the entry of:
When passing through a complex intersection, ignore the Intersection Identifier unless all of the intersection accidents are required.
Note: The Node String must be enter in order. Failure to list the Nodes in order will cause accidents to be omitted in included Links.
The Node String request will return all accidents associated with the desired section of road.
For example:
It will return all accidents related to the first
Node,
then all accidents between the first and second
Nodes,
then all accidents at the second Node,
and so on until all of the Nodes are processed.
Note: The Node String length may NOT be larger than 40 Nodes.
5 and 6. Primary Route Milepoint/Milepost
Requests
- The county
- The time period
- The direction of traffic
Note: The direction of traffic can be specified using a character that represents the direction of travel. Direction characters are:
B (Traffic Both Directions)
S (Southbound Traffic)
W (Westbound Traffic)
N (Northbound Traffic)
E (Eastbound Traffic)
O (Non-divided Traffic)
- The route number
- The beginning Milepoint(s) or Milepost(s)
- The ending Milepoint(s) or Milepost(s)
In addition to the Link Node location definitions, the user may also use the Milepoint or Milepost location scheme for accidents that occur on the primary road system (Interstate, US and State Highways).
These Milepoint/Milepost locations are derived from the Link Node location and are added to each accident in a process that occurs prior to receipt of the data by a PC-ALAS users.
Always keep in mind that the Milepoint/Milepost locations are conversions from the Link Node system. Therefore the Link Node method should be used for routes that have changed in the study time period. Since these values are conversions from the origina l Link Node location, it is possible for other types of errors to arise (although this is an infrequent occurrence).
In cases where a road is a shared route between two routes, the accidents are always coded to the route with the highest precedence.
By road system, the order of precedence starts with:
the Interstates
then US Routes
followed by State Routes
If two routes are of the same class, then the lower numbered route has precedence. Intersections of two Primary Routes should be viewed the same as Shared Routes.
Milepoints are 4 digit numbers that correspond to the distance from the western or southern county line, increasing as travel proceeds to the north or east.
The distance is given in hundredths of a mile. Milepoints can either be entered with an implicit decimal point (2424 = 24.24) or with a decimal point.
For example:
On a west to east Primary Road 24.24 would correspond to 24.24 miles east of the west county border.
The Milepost of an accident represents the location (in miles and hundredths of a mile) from the State Line. These values should directly correspond to the Mileposts that can be seen on the side of the road as one travels down each of the highways.
Milepoint and Milepost requests require the user to input:
7. Beat Requests (a user defined
geographic area)
- Quadrilateral (squares, rectangles, parallelograms,
or any other four-sided shape)
- Triangular (with two defining Nodes equal to each
other)
- Linear (with two pairs of equal Nodes)
- the user selects the desired "Beat file"
- then enters the desired time period
A Beat is designed for easy specification of geographic areas. It is defined through the use of 4 Nodes. These 4 Nodes define the corners of the desired area.
An area can be:
PC-ALAS simply figures the borders of the area through trigonometric calculations and decides which accidents were indeed inside the given area.
Running a Beat request is a two step process:
1. the Beat is defined for a particular area.
(This information is saved in a "Beat file" for later use)
2. when the actual request is desired:
8. Jurisdiction Requests
(by city, county, or state)
- By city (within a specific city's limits) - Use
a specific city number.
- By county (within a specific county's limits)
- Use a specific county number.
- In a specific county but outside all city limits
- Use city number: 00
- Statewide - use county number: 00
- Selecting View Old Reports option from the Report
menu
- Choosing CLIST.txt as the report to view
Accident histories are isolated by legal jurisdiction boundaries:
Note: City and county numbers can be found by:
Using the PC-ALAS Program
Notes for PC-ALAS
version 1.0 users
1. Starting the program
2. The desktop
The Desktop is the visual framework of PC-ALAS. It consists of the:
Menu Bar
Work Area (found in between the Menu Bar and the
Status Line)
Status Line
Windows, dialog boxes, and expanded menus share the Work Area. This Desktop area becomes the user's workspace.
The Menu Bar contains several menus containing PC-ALAS commands. These menus can be accessed by:
1. using the Mouse (clicking on a Menu's name causes
a "shade" of commands to appear)
2. using "shortcut keys" (ALT-F to open
the File menu)
3. pushing the F10 key
Once a menu has been opened, the user can move through
the rest of the menus with the keyboard's right and
left arrow keys. Individual commands can be selected
by using the up and down arrow keys. Pressing the
The Status Line contains various hot keys and special hints. The Status Line can be acced either by:
1. selecting it with the mouse or
2. by hitting the Hot Key that is show in red next
to the function
As processing proceeds in PC-ALAS, the user periodically has to supply information to the PC-ALAS system. One common medium for communication to the system is the Dialog Box. A Dialog Box is essentially a window that has:
1. entry fields
2. radio buttons or
3. check boxes in which to supply information.
Movement through each of the input media within a Dialog Box can be accomplished by either:
1. using the Mouse (to click on the desired input
element) or
2. using the Tab key.
An Entry Field, when highlighted, allows the user to supply text to the system. This can be:
a. a Node Number
b. a County Number
c. a Title or
d. other appropriate information.
Additional features allow the user to highlight a section of text with the Mouse and delete (with a single keystroke) or replace the highlighted text (by typing new text).
Radio Buttons allow the user to make a selection from a list of items.
For example: the user may select the output destination for a report.
With Radio Buttons it is only possible to select one element at a time. To make a Radio Button selection:
1. simply click on the desired list item with the
Mouse or
2. highlight the list with the Tab key (and use
the arrow keys to select the appropriate item)
The Space Bar is used to select or deselect items
within the list.
Check Boxes are used for lists in which more than one item can be selected simultaneously.
For example: a search based on vehicle type should accommodate multiple vehicle types.
To make a selection within a Check Box:
1. either click on the desired list element (to
select or to deselect it) or
2. use the Tab key to highlight the list (then use
the arrow keys to move within the list).
The Space Bar is used to select or deselect items
within the list.
A Dialog Box can be closed by:
1. using the Tab key to highlight either the OK
or the CANCEL button,
then either pressing the ENTER key or
using the Mouse to click on the desired button.
If CANCEL is selected,
no action on the contents of the Dialog Box will
be taken.
Note: A mouse user can also click on the small box in the upper left corner of the Dialog box to close it. This has the same effect as selecting a CANCEL button.
If OK is selected, the information within the box
will be processed.
Report Windows are used to display text. Usually this will be in the form of a report produced by PC-ALAS. This window can be resized by:
1. using the drag icons in the lower right corner
of the Report Window or
2. using the zoom command (Alt-F4).
Information can be scrolled with:
1. the scroll bars on the right and lower sides
of the window or
2. the arrows keys.
The Report Window can be closed with the Close command (Alt-F3).
3. Help utility
PC-ALAS also has a context-sensitive help utility function that has been integrated into the environment. This function allows the user to press the F1 key and get help for the part of the program being used.
For example:
if the user were entering the county field for a Location Request and was unsure of the exact county number,
the F1 key could be pressed for help in entering the county number as well as seeing a list of all the county numbers in Iowa.
A user can also jump between help screens by means of highlighted keywords that index other help screens via:
1. the Tab key or
2. the Mouse
The help function is an invaluable tool for a new user.
4. Running a locational search
The first step in any PC-ALAS request is to run one type of Location Search. This includes:
1. Specific locations
2. Beats
3. Jurisdiction requests
All three types of requests can be initiated from the Request Menu within the Menu Bar. Once the reqest is defined, the search will proceed. A message should appear at the bottom of the screen that says, "PC-ALAS is searching the accident database...Ple ase Wait."
After the data search is done, a Dialog Box will display the number of accidents for this location and you may:
1. Summarize the Locational search or
2. Further limit the accidents by some accident
characteristic.
5. County summaries
A new feature with PC-ALAS Version 2.2 was the ability to generate county summaries as far back as ten years (regardless of what data years your system currently had). This is possible by using the .hyp files which are located in the data directores. Hy p files are records that contain monthly summary information for the past ten years. These .hyp files can be used to generate:
1. The Summary Page and
2. The Age Summary Options
on your engineering and enforcement reports.
Note: Although summary information is available to you, the actual data is needed for other options such as:
a) Selecting accidents by accident characteristics
b) Producing case by case listings
c) Running ranking reports
d) Running specialy reports
6. Selecting accidents by accident characteristics
A powerful feature of PC-ALAS is the ability to select accidents based upon different criteria.
For example, you could:
1. First, run a Locational Search
2. Then, take those accidents and pick out only
the ones where one of the drivers was:
a. Between 19 and 25 years old and
b. Had a blood alcohol level greater than .08
Making this selection is as easy as:
1. Pulling down the Search Menu
2. Selecting one of the search categories
3. Pick the characteristics that you want to include
in the search
When all of the criteria have been selected:
4. Pull down the Search Menu
5. Select the option labeled, "Select Accidents"
This will:
a. search the accidents already isolated through
a Locational Search and
b. select accidents that meet the criteria
Once this is done, the user can either:
1) Select further using more criteria or
2) Generate a report
Logical Operators (And/Or):
When multiple criteria are used to isolate specific types of accidents, the logical operator AND is used by DEFAULT. In other words, for an accident to meet the supplied criteria, it must meet the conditions of every selection criteria.
Alternately, the logical OR operator may be chosen from the "Select Logic" option in the Select Menu. This would permit requests of the type where an accident qualifies if Condition A OR Condition B applied instead of Condition A AND Condition B.
7. Engineering and law enforcement
reports
PC-ALAS has a report format designed to meet more of the needs of the law enforcement community. This report format is similar to the old PC-ALAS report format. The main difference is that:
1. The night/day ratio
2. The surface condition summary
3. The accident rate
have been replaced by:
1. A time of day/day of week table and
2. A blood alcohol summary table
In addition, the case by case information has been expanded to include more information used by enforcement.
The Version 1 PC-ALAS report format is still maintained in the "Engineering Report". Both of these reports can be found in the Report Menu.
Once a report has been selected, the user has the option of generating any part of a report or the whole report. Also, the user can either:
1. Save the report to a file
2. Print the report or
3. View the report on the screen.
Report Headers (Generic/Custom):
When processing a report, the user fill be asked to input a Header Line or Lines depending on the Locational Request type. This function inserts a Custom Heading on the Summary Report. If a Header is not entered, a generic Header is used by the Summary Report.
Parameter/Search Criteria Sheet:
For verification of selection criteria and documentation of the parameters that were entered, it is suggested that the Parameter Sheet be printed for any report. This provides all of the information that generated the accidents included in the Current Re port.
In addition to the Header, the "Engineering Report" requires either:
1. The Daily Vehicle Miles (DVM = Average Daily
Vehicle x Mileage) or
2. The Daily Entering Vehicles (DEV)
to calculate the accident rate. These numbers can be calculated from traffic flow maps...available for every county by contacting:
the Office of Transportation Inventory
IDOT at (515) 239-1289
These maps have the ADT displayed for every section of road.
Calculating the DEV (Daily Entering Vehicles) is done by:
1. adding up all of the traffic around the intersection
and
2. dividing by 2 so that only the entering vehicles
are counted
These numbers will be used by PC-ALAS to calculate an accident rate for the requested study.
PC-ALAS also has the ability to save reports in a text file format. This allows the user to call up an old report to:
1. View it,
2. Print it, or
3. Import the report into a word processor
For accessing old report, utilities are available within the Reports Menu. These utilities can be used with any text file, not just PC-ALAS reports.
8. Ranking reports
The Ranking Report option is a new feature that forms intersection, nodal, and linkage reports based on three thresholds entered by the user. The three thresholds are:
1. Total number of accidents,
2. Total number of fatal accidents, and
3. Total number of personal injury accidents
The Ranking Report will then separate and list (in decreasing order) the various intersections, nodes, and links that meet at least one of these user thresholds.
The Ranking Report option can run out of memory if large data sets are being sorted (over 10,000 accidents). If this happens, simply:
1. Quit PC-ALAS and
2. Immediately type FULLRANK at the DOS prompt.
This should free up enough memory to produce the Ranking Report which will now be stored in the Rank.Dat file in the ALASDAT directory.
9. Specialty reports
Specialty Reports are reports that were originally made for individual users for specific circumstances. These reports were then incorporated into the PC-ALAS system.
When selecting the Specialty Reports option:
1. a file list will appear (with a list of the
current reports available)
2. clicking on the report name (will cause PC-ALAS
to produce the desired report)
To get an explanation of what each of these reports does, press the F1 key for the help utility.
These Speciality Reports will act on the current data set to produce the desired report. This report can be:
1. Viewed,
2. Saved as a text file, or
3. Printed
just like the "Engineering Report" or the "Enforcement Report".
Note: Although Special.Exe is listed under the
Specialty Reports,
it is not a report format.
It is only a file that stores the other reports
for backup purposes.
10. Special features
PC-ALAS has some features built into it that are worth mentioning. The first is the ability to exit to the DOS shell to:
1. Run another program or
2. Execute DOS commands
To reenter the PC-ALAS program, type EXIT at the DOS prompt.
In addition to the DOS shell function, PC-ALAS also has a built-in Screen Saver that has a user defined time delay. This function prevents the same image from being displayed for long periods of time and potentially damaging the computer's monitor.
PC-ALAS has features that can be customize for each user's taste. These include:
1. The location parameters,
2. The report option, and
3. The screen saver delay.
These default options are located in the Default Menu.
1. After setting the options as desired
2. Select the Save Options function from the Default
Menu.
The defaults are used:
1. whenever the program is started or
2. whenever you select the Retrieve Defaults from
the Default Menu.
The options retain their default values until you change them.
Miscellaneous
1. Third party users
If an outside agency or individual requests data from your system, considerations need to be made prior to releasing the data. Questions frequently come from:
1. concerned citizens and
2. persons involved in motor vehicle accident litigation
We will refer to these people as "third party users".
Prior to having PC-ALAS, you were probably asked for information about:
1. Accident rates at various intersections,
2. The safety of specific school crossings, or
3. The ages of drunk drivers involved in accidents.
Having PC-ALAS should permit you to respond to these questions asked by "third party users" to the extent you desire to respond. In most instances, you will be responding to them as a member of your own agency and following your own agency's policies gov erning the release of information.
For the following situations, contact:
Iowa Department of Transportation
Office of Transportation Safety
1. The hard copy PC-ALAS report is requested by
the "third party",
2. The "third party" wants information
specifically about driver reports,
(driver reports become the confidential property
of the DOT)
3. The "third party" is, or may become,
involved in litigation, or
4. The "third party" wants IDOT to vouch
for the data.
In addition, all such requests should be forwarded to the IDOT's Office of Transportation Safety.
If an error is ever discovered during the operation of PC-ALAS, it is important that the programmer be notified as soon as possible! This will permit:
1. timely correction and
2. notification of other users that an error has
been found
This notification should be given directly to:
the PC-ALAS programmer or
the Office of Transportation Safety
When reporting a program error, please take the time to:
1. document everything that led up to the program
failure
(so the programmer can quickly diagnose the problem)
2. send any printed reports or screen prints that
might help explain the situation
If the program error results in a program failure, or run time error:
1. Note all of the parameters used in defining
the request as well as
2. The sequence of steps used for the failing run
This information could prove invaluable in providing a timely diagnosis.
3. Making suggestions for program
improvement
For each agency, the users and uses of PC-ALAS may be vastly different. Many times, an agency using PC-ALAS has a good idea for making the program even better (easier to use, handling the data differently, etc.).
The PC-ALAS programmer welcomes any and all suggestions that advance the usefulness of this program. Some of the features that are currently a part of PC-ALAS, and many more that are under development, are the results of suggestions from accident data an d PC-ALAS users.
Your suggestions might also save time for others or supply them with additional information. So, please, send us your ideas.
To report program errors or make suggestions for improving PC-ALAS, direct all correspondence to the PC-ALAS programmer.
Troubleshooting
YOU ARE HERE!!! (Formatting decisions to be made!)
Extra help and information
Appendices
A. Troubleshooting
B. Error Messages
C. Obtaining Node Maps and Traffic Flow
Maps
D. Selection Criteria for Accident
Isolation in PC-ALAS
E. Selection Criteria for Accident
Isolation in PC-ALAS
Glossary
Index
last modified on January 9, 1997 by Michael D. Pawlovich (ISU/CTRE)
