An analysis (of traffic or anything else) is only as good as its data: Part 1 
          

Heather is lead researcher on Cherenzia's traffic analysis. Her post on trip generation will appear shortly. 

           On December 15, 2010, Bryant Associates of Lincoln, Rhode Island, submitted a “Preliminary Traffic Analysis” to Cherenzia Excavation, Ltd. A traffic analysis generally has three sections: a study of average daily traffic counts in an area; a study of the number of trips generated by residents of a new development; a distribution report that details the choices of routes to be taken by residents.

        It is standard procedure to use traffic data generated by the Connecticut Department of Transportation in the first section of such a report. Average Daily Traffic (ADT) counts throughout the state are available at The Traffic Count Locator on the DOT website. 

        Bryant Associates chose two sites in the Loop to capture neighborhood traffic counts.  The first is at the corner of Greenhaven just south of Sunrise.  It shows Average Daily Traffic as 400 vehicles. The second site is on Mary Hall Road close to the intersection of River Road. The ADT there is 1,200 vehicles. (At another level of DOT detail, these counts appear without rounding:  407 and 1,286.)

These sites seem to be odd choices.  The Greenhaven site is a half mile south of our Mary Hall Road intersection, a corner which will carry a lot more cars if this proposed development is approved.  A count at Sunrise does not correctly describe the amount of traffic flowing in and out of our neighborhood. The second site is also an oddity.  It counts the traffic on Mary Hall rather than the more important road into which it flows, River Road.  

          To better understand the ADT situation and how it could be used to accurately represent the traffic situation, I called the State Department of Transportation and spoke with Jackie Henry-Rafiq, supervisor of the Traffic Monitoring Section. She offered her professional opinion.

         “ I don’t think the count of 400 on Greenhaven Road is justified.  It’s too far away. There’s nothing below Mary Hall Road.  The road doesn’t go anywhere. In my opinion, the traffic count on Greenhaven north of the Mary Hall intersection more accurately represents the flow of traffic for the area.”

        She also supports the use of a site on River Road north of Rivercrest Drive as more “justified” than the site on Mary Hall Road. The ADT at Rivercrest is 2,300 and more correctly represents traffic flow in the area.

        We ended our conversation with an explanation of her job at DOT. “My function is to collect, analyze and report traffic data, not to say how the data should be used.”

       It appears that Bryant Associates has severely underestimated local traffic.  The ADT on Greenhaven is more correctly reported as 1,300, more than triple the 400 vehicles per day reported by Bryant. River Road traffic is more accurately reported at 2,300 versus 1,200.  

       To those of us who live in the Loop, traffic is a public safety issue.  We have only two roads out in a crisis.  The flood in March 2010 showed us our vulnerability. River Road flooded, the bridge on Greenhaven at Wequetequock Cove was compromised by a rising stream and backed-up tidal water.  

        When a developer proposes adding new members to our neighborhood, and potentially puts more residents in peril, I would hope they would use the most accurate traffic count possible. Thankfully, this is only a preliminary traffic analysis.  Perhaps Bryant Associates will step forward with corrections.




        
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