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OBD2LT & OBD2PDA  are the software programs you use to collect the field data to be processed in the office with PC-Travel or PC-LOS. The OBD2LT software runs on a laptop. The OBD2PDA software runs on commonly available Palm PDAs as well as on Pocket-PC type PDAs (iPaqs or Dells).

AutoLink__300_Instead of a GPS receiver you use an OBD Interface device. One end connects to a special connector in your car. The other connects to the serial port of a laptop or PDA. Shown here is the AutoLink from Northline Canada, which is the OBD interface we recommend. It is used to find the current speed of the vehicle as you drive the vehicle. The speed data is pretty accurate, generally around 1 MPH, which is fine for travel time studies or Level of Service studies.

To learn more about OBD interfaces in general and the AutoLink in particular click on the image or here.


These are the main screens you see when you are collecting data. The software is continually requesting the current speed from the OBD interface. This speed information, which is generated from 2 to 10 times per second depending on the type of vehicle, is summarized into one second averages and stored in the data file on the laptop or PDA. This data file is then processed in PC-Travel or PC-LOS to find the various statistics.

The advantage of an OBD interface is that is works in all conditions. There are times when it isn’t possible to use a GPS receiver. For example your route may include one or morel tunnels or large bridges where GPS reception is not good. In these cases an OBD interface can allow you to collect your data.

The disadvantage of an OBD interface is that it doesn’t collect positional information like GPS receivers so you can’t map the data and use the new mapping features in PC-Travel to edit the runs. The OBD interfaces are also considerably more expensive than GPS receivers.

The OBD software was developed for PC-Travel ver 1 when GPS receivers were more expensive and not as good in certain conditions. There also was no mapping option in PC-Travel so the data collected with GPS receivers and OBD interfaces was comparable. Now, GPS receivers are very inexpensive (less than $50), they work in almost all conditions, and the new mapping features of PC-Travel are very useful. You get the OBD software free with the PC-Travel Software Suite but it should be considered an option to use only when GPS doesn’t work.