One of the many uses of AI software is to examine traffic patterns to help plan construction projects. But how does the software work?
The environmental engineering firm Apex, which is consulting on the Envision Needham Center project, uses Vissim software. It conducted a traffic study on Sept. 9 to model future traffic flow along Great Plain Avenue to help guide consideration of the three proposed concepts for redesigning the downtown roadway.
“Vissim allows engineers to assess how proposed design changes, developments or policy scenarios will affect congestion, delay and safety performance,” said Amy Haelsen, Needham’s director of communications and community engagement, who noted the town itself is not using the software or another program, Placer ai.
The software analyzes roadway geometry, signal timing and driver behavior parameters to calculate various traffic scenarios, according to Haelsen. While phone data isn’t being used by Vissim to conduct an analysis, Replica, a similar traffic analysis AI program, does. Apex uses the software in conjunction with Vissim.
Replica receives data only from phones that have opted in through certain mobile apps that collect location information. These apps ask for permission to use cellphone users’ location for services such as weather and navigation. The only people included in the data are those who allow for these apps to have their location, according to information provided by Apex. The Replica software collects location pings that tell the company when a person is in a certain location, how long they’re there, and when they move. Personal content such as text messages, photos, contacts, or app usage is left out of the data collected, according to Apex.
In order to refrain from being a part of the collective data, cellphone users must turn off location services on their phone or opt out of location permissions for any apps that request it.
“Every time you link to a cell tower they can track and see who’s linking where,” said Select Board member Kevin Keane. “Your phone is a tracker, and they can just follow you.”
When asked how far the software can track you, Keane mentioned a case during COVID where the software tracked college students in Florida for spring break as they traveled back to their respective schools, mainly in the Midwest. The data was used to document a spike in COVID cases.
“It tracks every cell phone, and a lot of companies subscribe to it, and you can get a data dump. Pick a day and a location and they’ll go take a look,” said Keane. “It’s somewhat concerningly big brotherish, but the data and what you see and understand … is really amazing.”


