I need to scope out a traffic shortcutting study for a client and don’t have too much experience on this. Thought I may have seen a ‘how-to’ reference in one in your blog posts or emails. I don’t seem to find it so wondering if you would be kind enough to share any reference material on the matter.
Basically, I’m thinking on surveying plate numbers at both entry and exit points of the perceived shortcutting issue and matching up the plates from both ends. Essentially if a plate is registered at both entry and exit (within a certain time span) thus it is a shortcutting vehicle. Am I reasonably correct on my approach?
Here’s my response –
It’s been four or five years since I’ve done one of these, but I’ve done about a dozen of these types of studies in my career. I don’t know of any references on how to do this type of study.
It should be possible to use automatic license plate reading technology for this, but I don’t know of any portable systems on the market (and there doesn’t seem to be a big enough market to make it worth someone’s while to figure out). You could consider using a bluetooth matching system, like Traffax or BlueToad, but I think the sample size is too small inside a neighborhood to get accurate results.
You are on the right track. For neighborhood studies we manually record the license plates at the entry/exit points in 5 minute time intervals. That helps you match up someone cutting through vs. someone who parked at their home for a few hours. Our license plates are six digits long in Minnesota. If it’s a busier road (more than a 1,000 vehicles per day), we’ll tell our field people to just get the first four digits of the plate. You may also need to put two people at each entry/exit point, so a person can focus on a single direction. Binoculars might be helpful too.
I used to have an old DOS based program that did the matching, but we’ve just sorted using a spreadsheet of late. You could get into using a database if you have more than two access points.
On busier roads, we’ve used digital voice recorders with headsets and done the transcription back in the office (recording license plate, time, and direction) instead of writing things down in the field. Cell phones with voice recognition might be a good option now.
I typically put a few tube counters out along the route too. That way you can get a percentage of the total traffic that is cutting through. Most of the studies we’ve done have focused on a two hour window in the a.m. rush period and a two hour window in the p.m. rush period. You can obviously do more time, but be sure to give your field staff reasonable breaks.
For budgeting, you just need to add up all of the hours your field staff will be out and guess on your processing time. I don’t even have any rules of thumb to help you on that one.