Case Study No. 25
Prepared by Mike Dannemiller, RBA Group.
The New Jersey Department of Transportation (NJDOT) needed to improve pedestrian safety adjacent to State Route (SR) 46 in Denville, New Jersey. In Denville, SR 46 is a major highway that includes a jug-handle style intersection adjacent to the entrance of a large recreation facility. NJDOT needed concepts that were easy to install in a short timeframe, to mitigate this high vehicle/pedestrian crash location.
As part of an on-call planning assignment with NJDOT, The RBA Group was asked to develop methods to improve pedestrian crossing accommodations at the Savage Road/SR 46 jug-handle and Franklin Road. Near this location, SR 46 carries over 40,000 vehicles per day along its four- to six-lane cross-section. The posted speed limit on SR 46 is 80 km/h (50 mi/h). The posted speed limits on Savage and Franklin Roads are 56 km/h (35 mi/h). The surrounding area has residential and commercial land uses, public and private schools, as well as the recreation facility mentioned above.
There are signalized intersections along the highway, including a signal at one of the subject intersections. Westbound left turns off of the highway are accommodated via a jug-handle that connects to Savage Road, a local street. Savage Road and Franklin Road form a three-legged, or “T- intersection” adjacent to the recreation facility, which generates a large volume of pedestrian traffic. This intersection is just a half a block from the four-legged, signalized intersection of Franklin Road and SR 46.
A field inventory of the site revealed that westbound traffic on SR 46 seeking to turn south (left) onto Frank-lin Road, first exits SR 46 to the right onto the jug-handle, which uses a short one-way portion of Savage Road to access the Savage/Franklin intersection. This westbound approach has two travel lanes, one for left turns headed south on Franklin and one for through traffic onto Savage Road and other local destinations. East of the Franklin/Savage T-intersection, Savage Road is one-way westbound; west of the intersection, Savage Road is two-way. ADT on Savage Road is 7,000.
This creates a multiple threat situation for pedestrians attempting to cross the jug-handle leg of the intersection to the recreation facility (northbound), because the left turning traffic on the jug-handle is often backed-up at this intersection (from the Franklin/SR 46 intersection back through this intersection), blocking the pedestrian’s view of the fast-moving traffic on the jug-handle. Interviews reported that motorists traveling through the intersection along the jug handle were not likely to yield to pedestrians, due to poor visibility and a lack of awareness to pedestrians crossing the road. The frequency of pedestrians crossing Savage Road is estimated at approximately 25 per hour.
In-pavement lighting at crosswalk.
Illuminated crosswalk at night.
To better inform motorists when pedestrians are attempting to cross this multiple threat intersection, an illuminated crosswalk treatment was proposed. Public participation included a presentation before the Town Council, which passed a resolution in support of the proposal.
The proposed design was installed as a test location for NJDOT to determine if this treatment would generate a more appropriate sharing of the roadway, over more traditional high-visibility crosswalk striping. This system is extremely useful at stop controlled or mid-block crossing locations, but it is not appropriate at signalized intersections because of the potential for conflicting messages being presented to the motorists, such as a green traffic light instructing the motorist to proceed, and yellow flashing pavement lights instructing the motorists to yield.
The chosen system uses ultrasonic passive actuation, which does not require pedestrian users to take any action for the system to understand that they are there. This ensures that the pedestrians are detected by the system without having to push a signal activator. When the signal detects the presence of a pedestrian, the pavement-mounted lights illuminate. The lights stay on for 10 sec, flashing at a frequency of about 4 pulses/sec. These lights are similar in size to the typical highway pavement mounted reflectors, and are directed towards the oncoming motorists.
When the system is illuminated, motorists are presented with a series of flashing amber lights spaced several feet apart along either side of the crosswalk. These lights are easy to see, even in direct sunlight, and inform motorists that a pedestrian is actively crossing the roadway at that moment.
Project costs are estimated at $20,000 for materials, and $12,000 for installation equipment (labor is excluded from this estimate, as installation was done in-house by NJDOT).
While a full conflict analysis has not yet been completed, personal experience has shown that conflicts between motorists and pedestrians have been greatly reduced at the two crosswalks retrofitted with the illuminated crosswalk systems. Research conducted by the University of North Carolina Highway Safety Research Center in 1999 on a Florida DOT installation showed motorists yielding or stopping for pedestrians staged to cross the roadway increased from 13 percent to 35 percent after a flashing crosswalk was installed.
It is expected that illuminated crosswalks will be used to encourage motorists to more appropriately share the road with pedestrians by improving awareness for motorists that they are, indeed, sharing the roadway with non-motorized users.
After installation, feedback gathered from the local transportation agency suggested that Denville residents are very pleased with the improved “high-tech” crosswalk.
One Evergreen Place
Morristown, NJ 07962
Phone: (800) 722-9524
Huang, Herman; Hughes, Ronald; Charles Zegeer and Marsha Nitzburg. “An Evaluation of the LightGuard™ Pedestrian Crosswalk Warning System.” Prepared by University of North Carolina Highway Safety Research Center and Center for Applied Research for Florida Department of Transportation Safety Office, June 1999.