City Improves Pedestrian Safety with Promising Technology

How do we improve pedestrian safety in our increasingly multimodal transportation landscape? Traffic engineer Tom Sohrweide is counting his way to the bottom of it.

When a hospital expansion pushed employee parking to the opposing side of a busy four-lane roadway, the City of Burnsville, Minnesota, wanted to determine the safest, most effective way to get employees across the roadway. The project is now completed. The results are positive.

Stepping toward safer intersections

Initiatives all over the country have emerged looking to improve pedestrian safety. Among them are New York City’s Vision Zero, the National Complete Streets Coalition, America Walks and many others. Local or national, these initiatives arise out of a serious concern: approximately 10 people die each week in accidents on crosswalks in the United States.

After a hospital expansion, employee parking was relocated to the other side of Nicollet Avenue. Employees now cross at one of two crosswalks across a four-lane roadway. (Image: Google)

Officials in the City of Burnsville, Minnesota, share this rising attentiveness for pedestrian safety. Knowing that hospital employees would need to cross a busy four-lane roadway, the city examined a variety of crosswalk alternatives to find the safest option.

They considered alternatives including a standard crosswalk treatment, a signalized traffic system and a system that uses Rectangular Rapid Flashing Beacons (RRFBs), which feature attention-getting lights that flash in an irregular pattern, similar to emergency flashers on police vehicles.

After working with SEH to identify the safest option, the City selected and installed an innovative two-crosswalk system that uses RRFBs. The system also includes:

  • Advance pedestrian crossing signs
  • Pedestrian crossing signs on right side of roadway and median
  • “STOP HERE FOR PEDESTRIANS” signs in advance of crosswalk
  • Stop bars
  • In-pavement flashers

Once the system was installed, Sohrweide conducted a study to see if and how the system was influencing driver and pedestrian behavior.

In addition to other enhancements, the Nicollet Boulevard traffic control system includes RRFBs, a dual flasher that uses an irregular flash pattern that is similar to emergency flashers on police vehicles.

How safe is the solution?

Do pedestrians push the crossing button? Do drivers stop for them? How well do the RRFBs work?

These questions guided Sohrweide as he investigated how drivers and pedestrians interacted at the intersection. He conducted traffic counts and analysis on two different work days a week apart, strategically choosing to complete his counts during two of the intersection’s busiest times — lunch hour and shift change.

In his study, Sohrweide observed 185 pedestrian crossings, with vehicles present for 72 percent of them. He found that:

82% pedestrians pushed the RRFB button

16% didn’t push the button

2% crossed mid-block and didn’t use crosswalk.

Previous data collected by the Federal Highway Administration (FHWA) from intersections in a  variety of major U.S. cities shows that RRFBs improve compliance of vehicles yielding to pedestrians from 18 percent (before the installation) to 81 percent (afterwards). In other words, RRFBs are compelling drivers to put on the brakes. Sohrweide's study supports this, but his findings take safety even further.

Intersection safety surpasses expectations

What are people saying about pedestrian safety?

Sohrweide found that an impressive 96 percent of vehicles stopped for pedestrians at the busy Nicollet Boulevard crosswalks. His findings suggest that in certain circumstances a well-designed traffic safety system that incorporates RRFBs can outperform FHWA predictions.

“Pedestrians still need to exercise caution,” says Sohrweide. “But this technology is helping make great strides toward increased pedestrian safety.”

This is not the first time that Sohrweide and SEH traffic engineers have been at the forefront of innovative technology.  SEH won the 2011 Best New Innovative Product Application Award for its work on an intersection warning systems. Sohrweide’s traffic study and analysis on Nicollet Boulevard was recently featured in ITS International.

About the Expert

Tom Sohrweide

Tom Sohrweide, PE, PTOE, is an SEH traffic engineer and project manager dedicated to building safer transportation projects. His work includes traffic studies, traffic signal designs, traffic control, traffic signing and pavement marking design, roadway designs, Intelligent Transportation Systems (ITS) and more. Contact Tom

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