We have used CarTel to monitor urban WiFi connectivity. In a 2006 paper, we report on the results of about 290 total ``drive hours'' from a few cars under typical driving conditions, in and around the Boston metropolitan area. The study was done over a 1-year duration.

500 access points randomly selected from a set of over 13,000 found during the study are shown below.

* Wi-Fi Map (link takes you to a page showing just the map overlay)

Some graphs from this study are shown below. The full paper is here (Mobicom 2006).

The median connection duration is 13 seconds, the mean is 24 seconds.

The median number of bytes transferred per connection is 200 KBytes, the mean is 600 KBytes.

We're able to successfully associate at a good range of urban speeds.