On Tuesday 4/26, the team presented their finalized poster highlighting the design process at COSA (the Celebration of Student Achievement). The team fielded questions from curious students and professors regarding their design. The team also had discussions with school faculty members regarding what a potential real-life implementation of the proposed design would look like.

Following the conclusion of the exhibition, the team submitted their completed poster to the Department of Civil Engineering.

4/29/2022

For use in the final report and presentation, the vertical profile alignments for the project were creating using AutoCAD. These alignments were done in accordance with the NJDOT Roadway Design Manual and the American Association of State Highway and Transportation Officials. Seen below is an example of the vertical profiles created for the southernmost diverging diamond intersection.

4/20/2022

The roadway alignments for the proposed interchange have been completed in accordance with the NJDOT Roadway Design Manual and The American Association of State Highway and Transportation Officials. Lane and shoulder widths and sidewalks have been designed in accordance with the minimums specified in the NJDOT Design Manual, while the minimum curve radii have been designed in accordance with The American Association of State Highway and Transportation Officials.

This finalized plan will be supplemented by including the surrounding existing conditions and placing the design onto a finalized sheet with a title block. A signage and striping plan, as well as a plan with roadway dimensions and radii have also been prepared, but are not being placed on the team's design poster for purposes of space.

3/29/2022

The pavement design for the proposed interchange has been calculated using values obtained from field observations, NJDOT traffic data and engineering judgement. The values were used in Formula 4.1 from Mannering & Washburn's Principles of Highway Engineering and Traffic Analysis to obtain the pavement's structural number. Structural coefficients from the same textbook were then utilized to create a final pavement design which would satisfy the calculated structural number. The final pavement design consisted of 2" of hot mix asphalt wearing surface, 5" hot mix asphalt base, and 11" crushed stone subbase.

Using this pavement design, normal sections were created to show a cross-section of the proposed roadway at selected segments. The normal sections were created in accordance with the examples provided in the New Jersey Department of Transportation's 2015 Roadway Design Manual.

3/10/2022

Normal Section for Northern Approach of US Route 202

A simulation of the proposed design's key elements was completed, including the roundabout, the diverging diamond interchange, and changes to volumes moving throughout the system. With the simulation complete, the level of service could be analyzed, and the design could be adjusted to improve the level of service wherever possible. Along with this, the signal timings between the northern and southern intersections of the diverging diamond interchange could be adjusted to fine tune traffic flow through the key aspects of the system.

The future steps in terms of the simulation are to produce level of service analysis reports for the different parts of the infrastructure in place, implement changes in signal timings to simulate pedestrian interactions, and finally fine tune the simulation to better replicate real life conditions wherever possible.

2/28/2022

VisSim Simulation Overview

Distinct project areas were drawn out as well as a baseline stationing system to determine where each group member's work ended and the next began. These station boundaries will be used to allow the team to work separately and simultaneously to compile the end results into a singular file. A completion date for the proposed design plan was set at March 1st. This will not include construction plans and will only be used for the general site overview for layout, striping, typical cross-sections, and signage.

Traffic counts were increased based on 1.0% compounding population growth over 10 years in order to simulate conditions for the near future of the project, rather than exisiting conditions that will be removed. A VisSim model for this purpose is in progress.

2/15/2022

Updated Traffic Count Graphic

Using peak volumes found from NJTMS traffic counts along with traffic counts taken during site visits, a VisSim model of the existing conditions was found. The NJTMS peak volume was taken from the WB on ramp to US Route 202, and was the basis for all other counts used in the volumes. The individual counts were converted to weighted percentages where the weight was derived from the site visit traffic counts. The phasing for the signalized intersection north of the Somerville Circle was based on the traffic volumes taken, as well as anecdotal evidence from the site visit. Yield and stop signs were placed based on google maps and google street view. After all inputs were accounted for in VisSim, the simulation was ran, and the level of service at several major intersections at the site were determined. Level of service varied from A to F, with F being at several of the potential routes along the circle drivers could take. A visualization of the model can be seen in the attached picture. Eventually the level of service for these routes can be compared to the proposed alternative in the future.

11/27/2021

Parking study data has been compiled, and processing has begun to evaluate the feasibility of the team's design. Peak hours and peak volumes were estimated for each parking section based on the collected data. For the Petco-Burlington parking area, the peak hour was 12:00 pm, with 172 vehicles. The P.C. Richard and Son parking lot had a peak of 20 vehicles at 12:45pm, and the BuyBuy Baby parking lot had a peak of 16 vehicles at 12:45pm. In the Somerset Shopping Center lot, the peak was 201 vehicles at 12:30pm. Current calculations show that the Petco-Burlington lot and the BuyBuy Baby lot are using under 31% of their capacities. This gives plenty of open space for construction to occur without disrupting normal business patterns.

The team also made progress on the work breakdown and pay chart for each member and faculty advisor. Tasks were categorized and hours were distributed based on each member's contribution to the project. All tasks for the Fall semester have been accounted for. Each task for the Spring semester has been given a rough estimate, which will be revised in the future.

11/15/2021

Alternative designs were refined further in CAD so that a better idea of what alternatives may look like were made. Alternatives for the parking lot entrances were also refined within designs. In each design, parking lot entrances close to the Somerville Circle were removed on Easton Road. The signalized intersection connecting to parking lots was kept in some way shape or form in each design. In one variation, the entrance is not modified, in another, the entrance is shifted back further, and in the last, a roundabout was used in place of the intersection. This roundabout was not centered on the current center of the intersection, but was shifted to the side somewhat so that the curve into the BuyBuy Baby parking lot was not as sharp. In addition to these potential changes, the idea of a frontage road was also presented. This road would connect all parking lots on one side of the road so that cars could travel quickly between parking lots and exit these parking lots with a reduced number of entrances and exits to Easton Road.

After creating a weighted decision matrix, the best alternative design was chosen. The matrix criteria included: aesthetic, service life, maintenance, time for construction, cost, constraints, introduction to new traffic patterns, and safety. The weights per metric increased by 1 in that order, starting from 1, ending at 8. Each design was assigned a unique value for each criteria ranging from 1 to 3. The score assigned multiplied by the weight of the criteria gave the value earned for that criteria. Summing all the scores per design showed that Alternative Design 2 was the best, with a score of 91. This design used a diverging diamond interchange in place of the Somerville Circle, while partially keeping NJ Route 28 (West End Avenue) by converting a segment of it to a one way, so traffic could still flow out of the interchange. Traffic that previously went northbound on West End Avenue into the Somerville Circle would be diverted onto Frelinghuysen Avenue. Frelinghuysen Avenue would be widened, potentially adding a lane depending on traffic volumes. For the parking lots north of the Somerville Circle, entrances would be removed, while the signalized intersection connected to entrances would be converted into a roundabout allowing traffic to flow constantly, but slowly, allowing for pedestrians to be able to safely cross still with crosswalks. A frontage road would also be incorporated, so that people using the parking lots would not be hindered by the removal of parking lots.

10/29/2021

The final site visit was complete on 10/14/2021. Out of the four site visits, 3 were for traffic counts, and 1 was for parking studies. The two most recent site visits were completed on 10/7/2021, and 10/14/2021. The first of the two completed traffic counts on the intersection of Frelinghuysen Avenue and US route 206, along with the intersections of West End Avenue with Frelinghuysen Avenue and Cornell Boulevard. This allows for the group to decide if changing these intersections to divert traffic potentially from West End Avenue onto US-206 was a viable option. The second site visit completed parking studies to understand the required max capacity the parking lots may have and to check if downsizing parking lot spaces may be a vallid option. This played into the alternative designs that were thought up as potential solutions. Alternative 1 would potentially remove the roundabout by creating new roadway for a diverging diamond interchange with new ramps in its place. This design would also remove the current West End Avenue approach to reduce the number of approaches. This would require a redesign of the two intersections of US-206 and Frelinghuysen as well as West End and Frelinghuysen to take in diverting traffic. Alternative 2 is similar to alternative 1 with the major difference being that the West End Avenue approach is kept as a one way out of the circle, allowing for better flow potentially. This would require less change on the two intersections alternative 1 would have required. Alternative 3 aims to be somewhat more cost effective then alternative 1 and 2 by using the preexisting roundabout roadway as part of the new diverging diamond interchange, while still keeping the idea of a one way on West End Avenue. As constraints are further finalized, the potential alternative designs would also be completed.

In addition to the site visits and alternative design ideas, speed data was also analyzed for the various approaches to the roundabout wherever existing anonymous probe vehicle data. Data was used from the whole of 2019, so that cumulative frequency diagrams could be made showing the spread of speeds. This would work as a potential constraint as new ramps and curves could be designed with current speeds in mind to make the transition to a diverging diamond interchange from a roundabout easier for users.

10/14/2021

The team has fully completed analysis of available traffic counts through excel of the available traffic count stations around the project area. This would allow for traffic volumes during peak hours to modeled in synchro later, as well as understanding the capacity that any proposed designs may need to satisfy. Site visits to be conducted on the weeks of 9/27/2021, and 10/4/2021 would show percentage of vehicles using specific turns. This percentage combined with known volumes would allow for more accurate Synchro modeling of traffic flow. Stations that were used and their locations are shown in an attached figure.

The team has also completed acquiring elevation points for the site, creating a contour map the potentially affected region. This would allow for vertical and horizontal alignments to be completed based on the CAD drawing of preexisting conditions.

For the upcoming site visits, parking study graphics were prepared so that the number of necessary parking spaces could be analyzed in case a proposed design may need to reduce the number of spaces.

9/29/2021

The team has completed CAD drawings on Civil 3D of the preexisting conditions of the Somerville Circle and applicable surrounding roadway infrastructure. This drawing was completed through the use of a scale map of the location available through Civil 3D, originating from Microsoft Bing. The key points of the project were included in the CAD drawing. This included road approaches to the Somerville circle roundabout, as well as intersections south of the roundabout that would potentially be changed. This included Frelinghuysen Ave, Bell Ave, and Sherman Ave, at their intersections between each other, and with US Route 206, and NJ Route 28. Parking lots north of the roundabout that may potentially be changed were also included within the CAD drawing. Examples of the CAD drawings are shown.

Traffic volumes were also collected from available stations on impacted roadways through NJDOT's Traffic Count Stations, available on njtms.org. 7 day and 2 day counts were used, providing Annual Average Daily Traffic counts giving an estimate of daily traffic volumes, and as well as hour by hour counts. This would allow for a better understanding of the required roadway capacities, providing volume constraints, as well as hinting at the potential peak hours of the roadways. An hour by hour average of weekdays for each of the data sources was conducting to understand peak hour volumes to design around. An example of US Route 202 northbound is shown.

9/21/2021