Frequently Asked Questions
- How accurate are the speeds and hourly traffic volumes?
Traffic speeds are obtained by radar are very accurate down to about 5 mph. Speeds below that are not necessarily accurate, but for our purposes when speeds get that low, we already know there is significant delay. The speeds are averaged every few minutes, so there could be a momentary delay (turning vehicle, farm tractor backing traffic up, etc.) that would seem to indicate major delays – that is why visual confirmation with the web cams is made before a delay message is posted. Messages are posted when speed drop below 25 mph at the 50 mph monitering locations.
The hourly traffic volumes obtained by radar are not accurate and are not used. That is because they are obtained by the number of radar hits made over a 10 to 15 minute period. There is a possibility that some vehicles are “hit” by the radar more than once as they travel through the radar detection zone, for instance. We will use the permanent traffic counter numbers for data evaluation purposes. Both northbound and southbound traffic volume data are obtained from the permanent traffic counter located near Wiscasset Ford.
- When are the 511 system and variable message signs activated?
The 511 travel advisory system and the I-295 Freeport variable message sign are activated only when a major delay occurs. A major delay is symbolized by a red “I” on the web cams page. The system is not activated for minor delays, symbolized by a Yellow “I”. major delays are when speeds drop down 25 mph at the speed monitering locations.
- Can we obtain copies of web cam photos or video?
Photographic information is not stored, so it is not available.
- I want to analyze the data – how can I obtain it?
We are collecting a lot of data so the data files are very large. Data is available on request.
- Why does the web cam image appear to be frozen?
Due to bandwidth and security limitations of the state web site, the web cam images are refreshed every few minutes.
- Why is the southbound variable message sign in Edgecomb so close to Route 27?
The Edgecomb Variable Message Sign is a stand-alone system that informs southbound traffic that vehicles ahead are stopped.
- Will the Traveler Information System be expanded?
MaineDOT expects a more robust systemwill devlop over time.
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