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Phase: Construction - Spring/Summer 2023

Purpose and Need: Improve network connectivity and integration with proposed Brunswick Circle Extension Roundabout, allow for safer turning movements and improve road safety for drivers, cyclists and pedestrians.

Background:  

This project is one of several planned projects for “Mercer Crossings” which is an area at the confluence of three municipalities (Ewing Township, City of Trenton and Lawrence Township). This is an area with a high density of local businesses, residences and aging roadways under County jurisdiction. As part of the County’s planned Mercer Crossings Improvements Program, Mercer County is making several improvements to the Princeton Avenue corridor as well as the intersection of Mulberry Street and Princeton Ave throughout 2023 and early 2024. Mercer County will also be undertaking future signal system upgrades at intersections near the project intersection including Princeton Avenue & Spruce Street (CR 613), Princeton Avenue & Olden Avenue, and Olden Avenue & Arctic Parkway (CR 639).

In collaboration with Ewing and Lawrence Townships and the City of Trenton, Mercer County has developed a phased conceptual plan for converting the intersection of Princeton Avenue (CR 583) and Brunswick Circle Extension (CR 645) into a single‐lane modern roundabout and implementing a road diet on Princeton Avenue from Brunswick Circle Extension to Olden Avenue (CR 622). The current Y-intersection of Princeton Ave and Brunswick Circle Extension has a significant amount of crashes and conflicting traffic operations. Crashes at this intersection are much higher than the statewide averages for similar intersections while pedestrian and cyclist crossings are currently difficult if not impossible.

The existing Mulberry signal currently operates with three-phase operation because of the 70-foot offset between Mulberry Street and Farmers Market driveway intersections with Princeton Avenue, where each side street has its own signal phase to accommodate traffic flow without conflicts between the various turning moves. Three-phase operation splits the total green time between the three roadway approaches, limiting the green time for each approach. This is an inefficient use of signal green time and leads to operational deficiencies.

Proposal:

The Mulberry signal will be completely reconstructed to operate in 2 phases, allowing a more efficient use of green time. The Trenton Farmers Market rear access will be redesigned to a right-in/left-out only. This will reduce the number of conflict movements and allow Mulberry Street’s major left-turn movement to act concurrently with the TFM access movements as well as pedestrian movements across Princeton Avenue.

Those who are driving Northbound on Princeton Ave and wish to access TFM may do so by utilizing the Two-Way-Left-Turn-Lane to turn into the stop-controlled driveway located between the Car Wash and Dunkin’ Donuts. As part of this project, the TFM rear access will be regraded and repaved to match Princeton Ave existing grades, providing for a more appropriate slope for vehicles to traverse. The current conflicting slopes prevent timely and inefficient operations in and out of that driveway. This results in longer wait times at the signal reducing the number of vehicles that enter and exit during each signal phase.

The County was awarded a federal Highway Safety Improvement Program (HSIP) grant for the roundabout conversion and is anticipating to bid for construction in late 2023. the Princeton Ave road diet and Mulberry signal upgrade continues through Spring into Summer of 2023. More information regarding the modern roundabout conversion can be found at the following link:

https://www.mercercounty.org/departments/planning/transportation-projects/bce-roundabout

Road Diets:

Overall, road diets can help create a safer and more welcoming street environment for all users, which can lead to improved quality of life for residents and visitors.

Four-lane undivided highways have a history of relatively high crash rates, especially as traffic volumes and turning movements increase. A principal cause is that the left, or inside lane is shared by higher-speed through traffic and left-turning vehicles. The Federal Highway Administration (FHWA) has recognized road diets as a proven safety countermeasure, as they have been shown to reduce the number of vehicle-to-vehicle conflict points that contribute to rear-end, left-turn and sideswipe crashes, provide safer facilities for bicyclists and pedestrians, manage speeds and improve a community's livability. Road diets are becoming standard practice across the country.

Communities in many states, including New Jersey, have implemented road diets and realized their benefits. Because most road diets can be installed on existing pavement within the right of way, they can be a low cost way for a community to achieve many goals. FHWA, NJDOT and Mercer County all support creating road diets where appropriate.

Road diets can offer several safety benefits, including:

• Reduced vehicle speeds: By reducing the number of travel lanes, road diets encourage drivers to slow down, reducing the severity of crashes and giving drivers more time to react to unexpected situations. These crashes result in less serious injuries and reduce number of fatalities.
• Fewer conflicts: Road diets can reduce the number of conflict points between vehicles, bicycles, trucks, buses, and pedestrians. This results in a reduction in the likelihood of collisions. Road diets can have a crash reduction of 19 to 47 percent and in certain circumstances can reduce crashes by up to 70%.
• Improved visibility: By creating a narrower street with better marked lanes, road diets can improve visibility for drivers and pedestrians, reducing the likelihood of crashes caused by obscured sightlines.
• Allow for safer turns: By creating a center turn lane, drivers have a dedicated space to pull in and out of local businesses which is difficult with four lanes of traffic and no center turn lane.
• Integration into modern roundabout: A road diet allows for a seamless transition into modern single lane roundabouts over a longer distance.
• Increased bicycle and pedestrian safety: Road diets can create space for dedicated bike lanes, bus pullouts and pedestrian crossings, improving safety for these users who are often vulnerable in multi-modal environments.
• Reduced crossing distances: By adding a center turn lane and crosswalks, road diets can reduce the distance that pedestrians need to cross the street, reducing exposure to traffic and improving safety.
• Provides safer and more efficient travel for emergency vehicles by providing better sight distance, less lanes to cross and a center turn lane that can be used to avoid traffic, leading to a positive effect on EMS response times.

                                            Please click on the video link above for more information about Road Diets.