Intersection of Cherry Hill Road, Mt Lucas Road, and US-206 in Princeton. (click to expand)

Earlier this year, the town of Princeton closed part of Terhune Road to provide space for a parking lot for a new PFARS ambulance station. The town did not have a workable traffic management plan in place at the time of the road closure, and drivers who formerly used Terhune Road to access Route 206 have mostly detoured to the intersection with Cherry Hill Road. Neighboring residents have found that the intersection of Cherry Hill Road and Route 206 is now subject to serious delays, and drivers struggle to safely turn onto Route 206. To try to resolve these issues, the town hired consultants to attempt to find ways to speed traffic through the intersection. In a report to Council in July, they suggested design changes for the intersection that might improve the flow of car traffic.

The problem area: Closure of Terhune Road at US-206 has worsened back-ups at the intersection of Cherry Hill Road and US-206. (click to expand)

The consultants, from the ‘WSP’ firm, were hired by Council in January, for $70,000, without competitive bidding. At the Council meeting on July 8, lead consultant Peter Kremer and his team reported findings from their traffic study. The consultants found that drivers on Cherry Hill Road entering the intersection at Route 206 in an east-bound direction can face lengthy delays, and that delays are worst during the morning rush hour. On a grade scale where ‘A’ is free-flowing traffic and ‘F’ is ‘total congestion’, this route scores an ‘F’. For drivers on Cherry Hill Road heading west toward the US-206 intersection, things are also bad. This trip scores an ‘E’ overall, and an ‘F’ for drivers trying to turn left onto US-206.

The consultants recommendations are:

• Alter the timing of the traffic signal at Cherry Hill Road and US-206, so that 2 seconds” per light cycle will be added to the green phase for drivers entering the intersection from Cherry Hill Road.
• Re-strip the approaches to US-206 on Cherry Hill Road. East-bound, drivers will have a dedicated left-turn lane, and another lane for drivers continuing straight ahead or turning right. West-bound, the road will be split into three lanes: one for drivers turning left, another for drivers going straight ahead, and another for drivers turning right.

These changes are expected to improve conditions for drivers on Cherry Hill Road, but only up to a point. Drivers heading east on Cherry Hill Road will see an improvement in conditions from an ‘F’ grade to an ‘E’ grade during the morning rush hour. Drivers heading west on Cherry Hill Road into the US-206 intersection will see an improvement from an ‘E’ grade to a ‘D’ grade – except for drivers trying to turn left from Cherry Hill Road onto US-206, who will still be at an ‘F’. As some of the green signal time is being re-allocated, drivers trying to go south on US-206 during the morning rush hour will see increased delays. However, the delays will only reach a ‘D’ grade, which the consultants believe will not be a deal-breaker in trying to persuade the state Department of Transportation, which operates US-206.

Summary of consultants’ recommendations. (click to expand)

Members of Council and local residents wondered if other options had been considered, but most alternatives are unworkable for one reason or another. The idea of re-opening the closed section of Terhune Road was dismissed by Council Member Eve Niedergang, who pointed out that the Princeton First Aid and Rescue Squad wanted the space, and Council had already agreed to give it to them.

The option of allowing left turns onto US-206 from Valley Road was also discussed. This would take the pressure off the Cherry Hill Road intersection, but the consultants concluded that it is unsafe, because of the volume of traffic and restarted sight-lines. Left turns could be made safely if a traffic signal was added, but the state Department of Transportation will not allow it, because the traffic signal would be too close to the traffic signal at Cherry Hill Road. They are willing to allow an emergency traffic signal for occasional use by the ambulance station, but it turns out that there is not even enough space to build an emergency signal. The land on the west side of US-206 is protected by the state “Green Acres” program, therefore it is either difficult or impossible to build any traffic signal at this intersection to the appropriate standards.

Local residents also complained that the intersection is dangerous for pedestrians, especially since the town built a gas station for municipal vehicles next to the site of the new ambulance station. The consultants said that their plan involved adding sidewalks at three places near the intersection with Cherry Hill Road and US-206, although sidewalks already exist in each of these places. The consultants agreed that the geometry of the intersection of Terhune Road and Mt Lucas road is dangerous for pedestrians crossing, but had no specific suggestions about how to improve this. The needs of cyclists using the intersection were not even discussed, although the town notionally subscribes to a ‘Complete Streets’ policy, under which requires all roadway projects to “safely
accommodate travel by pedestrians, bicyclists, public transit, and motorized vehicles.”

Newly-built municipal gas station and under-construction ambulance station on Mt Lucas Road. (click to expand)

Although Council did not specifically pass a resolution endorsing the recommendations of the consultants, there was a consensus that the process should move forward. If the intersection modifications are approved by New Jersey Department of Transportation, drivers may see the changes happen as soon as this fall,

The slides from the presentation are available at the municipal website at this link (archived here). The presentation of the consultants to Council, and subsequent discussion, can be viewed below, running from  0:27:34 – 2:04:50.