Once you’ve been given a traffic study to work on, you have two tasks to get done in short order – (1) order the traffic counts you’ll need and (2) visit the site to document the existing conditions. You may need to tweak your data collection plan based on your field visit, but I recommend you get the data collection on the schedule ASAP and adjust as needed. That parallel process has allowed me to get traffic studies done faster than doing the linear field visit then traffic count process.
To do your field check as efficiently as possible, I recommend you start with your favorite aerial online site or software (MapquestTM, Google EarthTM, BingTM, Google Street View, County/City/State GIS Maps, etc.). It's actually best to look at a few online aerials to find the most current one. I especially like the angled birds eye view Bing offers and Google's street view.
Draw a sketch of each study intersection based on the aerial (a quick and dirty pencil sketch by hand will work) with the following details:
- Exclusive left or right turn lanes (measure their storage lengths and include it on the sketch)
- Through lanes (and/or shared lanes if turn lanes aren’t provided)
- Stop sign locations
- Traffic signals
- On-street bike lanes
- Nearby parking lots
- On-street parking
- Street names
If time permits, I have my technician create a figure from my hand sketch that I can take in the field with me (such as the one below). Also print out a street map of the study area to take notes on. Make sure it is zoomed in enough so you can make notes of things that are between your study intersections.
I find I am more accurate correcting my sketches in the field than trying to draw them from scratch while I am on the side of the road. I always seem to miss something if I skip this first step in the office.
Next week I’ll post a checklist of what I look for when I'm out at the site.