Casey Overpass Planning & Concept Design
Traffic Highlights
Data Collection: • Extensive local study area includes 17 intersections (11 signalized & 6 unsignalized). • Regional modeling performed by the Central Transportation Planning Staff (CTPS) • Traffic data collection: In June 2010 manual turning movement counts (MTMCs) were collected during peak periods for vehicles, pedestrians, and bicycles and seven‐day automatic traffic recordings (ATRs) were collected. • Accident data was collected for each of the study area intersections for the most recent three year period available (2006‐2008). • License plate data on Casey Overpass and at 5 parking lots was collected in November of 2010 and was used to identify vehicle origins and validate the regional model. Existing Traffic Volume Facts: • The average daily traffic (ADT) volume on Casey Overpass is approximately 24,000 vehicles per day. There are approximately 12,000 vehicles per day on New Washington Street. Detailed volumes are depicted in the Existing Conditions: Traffic Highlights document on the project website ‐ http://www.massdot.state.ma.us/caseyoverpass/traffic.html • High pedestrian crossing activity occurs at a number of locations with 11 crossing locations having more than 50 pedestrians in the peak hour. • Moderate bicycle activity occurs at a number of locations with 10 crossing locations having more than 20 bicycles in the peak hour. • The weekday morning peak hour occurs from 7:15AM to 8:15AM. • The weekday evening peak hour occurs from 5:00PM to 6:00PM. • The midday peak hour is lower than both AM and PM peaks. • Accident rates are below MassDOT averages, except Shea Circle. • Existing conditions analysis has been completed and calibrated based on extensive field observations. Existing operations are hindered by roadway geometry and the effect of queue spillback between intersections. Future 2035 Traffic Volume Facts: • Future 2035 traffic volume projections assume no change to local roadway infrastructure and are intended for initial planning use only. Updated volume projections will be developed for the individual design alternatives. • Future 2035 traffic volumes have been projected using the CTPS regional model and incorporating specific local development parcels identified by the Boston Redevelopment Authority (BRA). • The initial projections for the year 2035 show an approximately 5% increase in traffic volume on the Casey Overpass and an average increase of approximately 14% for traffic volumes on the local surface roadways, assuming no change to the Overpass or the local roadway network. • Pedestrian and bicycle volumes are initially shown to grow by 13%. • Transit usage is projected to increase by 10%. May 13, 2011 Next Steps: • Future‐year 2035 Traffic Analysis of existing roadway network to establish a baseline condition. • Conceptual Idea Screening of potential designs. • Detailed traffic analysis of Design Alternatives. • Regional modeling of design alternatives to project alternative specific 2035 traffic volumes. • Refined analysis of Design Alternatives using alternative specific updated future year projections. May 13, 2011