Summary of the FSP Project, Database, and Software

Description of the database.
Description of the support software.

I-880 Database

The study:

In order to estimate the delay savings attributable to the FSP, data was collected over two time periods: once when the FSP was not in operation (the ``before'' period) and once when the FSP was in operation (the ``after'' period). The before study took place from February 16 through March 19, 1993 with the after study taking place from September 27 through October 29, 1993. All of the data was collected on a section of the I-880 freeway in Hayward, California. The study section was 9.2 miles long and varied from 3 to 5 lanes. An HOV lane covered approximately 3.5 miles of the study section. There were several sections that lacked right-hand shoulders and/or left-hand shoulders. Call boxes were installed at approximately 1/4 mile intervals but that data was not used for the evaluation project. Probe vehicle data was collected on the weekdays during the peak periods (6:30 - 9:30 am and 3:30 - 6:30 pm). And loop detector data was collected from 5:00 - 10:00 am and then again from 2:00 - 8:00 pm. For each study period we collected three different types of data: loop detector data, probe vehicle data and an incident characteristics database.

Probe vehicle data:

During the course of the experiment there were four or five probe vehicles that were driven around the study section for approximately 2.5 hours in the morning and 2.5 hours in the evening. These vehicles were equipped with computers that recorded the car's movement and the driver's key presses and then saved these to various files on a PC floppy disk. We get a total of four files from each car for each run. They are currently named: key.dat, fsp.dat, nav.dat, and gsp.dat.

Loop data:

The loop data is pretty straight forward in that there is only one file per cabinet per day and it isn't even in ascii text so we can't read it. The loop data consists of the output from different loop detectors. A loop detector is just an inductive loop that is buried under the freeway that picks up the presence of a vehicle traveling over it. On the main line lanes the detectors are placed in pairs, but on the on and off ramps they are single detectors. From this data the program calculates the number of cars that pass over the detectors their average speed and the average occupancy per period.

Incident database:

The incident data is one database file with approximately 80 columns of information per incident. The database was collected during the experiment by the drivers of the probe vehicles. When they were driving around the freeway and they passed an incident they would radio it in to the command center (a person sitting at Denny's). Their report would go something like, ``There's a stalled green passenger car, southbound, about 1/2 mile before 92. They are getting assistance from the FSP guy now. There is also a CHP on the scene.'' All of this would be written down by someone at the command center on a standard form. This form was then coded into a database with numerical entries in each column so that a computer could process it later. The database format was devised by Hisham Noeimi and Dan Rydzewski.

Support Software

Note that the latest version of the support software is fsp 1.1.

The FSP Program

The fsp program is a software tool used to interrogate the data that was collected during the Freeway Service Patrol Evaluation Project. This program will perform diagnostics on the data, generate error reports, and make plots of various pieces of data. The program takes as it's input arguments a file called a runfile, an incident filter file, and an incident run number. The runfile contains all of the commands that the fsp program needs to run. The incident filter tells the program which incidents to filter out of the incident database and the incident run number is just an index for the output files.

The XFSP Program

The xfsp program is a graphical user interface to the fsp program that was written in Tcl/Tk and Expect. This program allows the user to generate the runfile and the incident filter by clicking on various buttons and widgets with the mouse. This program requires that you have the xfsp support programs installed on your machine.