Walking through some ideas for improved pedestrian safety

  • 13-May-2014 09:33 EDT
aei-pedsafety5.jpg

Creating a yellow-line-marked lane for turns also results in a safe standing area for crossing pedestrians. The design shown incorporates raised "islands."

"Everyone is a pedestrian" is a traffic safety dictum of NHTSA (National Highway Traffic Safety Administration). That's pretty obvious, but America's pedestrian safety record is not one that reflects any sign of improvement. Nationwide, the many mandated vehicle safety improvements have reduced the total number of fatalities, but only in the area of drivers and passengers. Pedestrian fatalities are virtually unchanged.

The numbers: 43,005 fatalities in 2002, including 4851 pedestrians; drops to 33,561 in 2012, including 4743 pedestrians. So although pedestrian fatalities were 11% of the total in 2002, they're now 14%.

A conference on pedestrian safety held at the recent New York Auto Show focused on where and when pedestrian accidents occur. It considered the pros and cons of possible solutions, featuring speakers from local, state, and federal agencies. And for "thinking out of the box," it added a contest in which college students exhibited models of hardware solutions.

Encouraging 'yield'

There is no one answer and no one program, the speakers emphasized.

"It's a marathon," with some specific approaches for each of the many causes, explained Arnold Anderson, police detective with the Essex County (NJ) Community Traffic Safety Program. He cited a Montclair, NJ, program that encourages drivers to yield to pedestrians and asks pedestrians to indicate thanks to the drivers who do. The campaign was accompanied by signs with the measured results (using police "decoys" to secretly monitor the crosswalks) at key locations in town.

A New York City study of fatalities in 2008-12 said 53% were caused by driver choices, 30% by pedestrian actions, and 17% by both. Further, 73% of the fatalities occur in urban areas and 77% at locations other than intersections. Injuries to pedestrians were not  precisely classified.

The solutions fall into three categories: changing the road configurations, educating driver and pedestrian, and making improvements to the cars.

There are many, proven ways to reconfigure roads and intersections to improve their safety for pedestrians, the conference was told by Emmett McDevitt, transportation safety engineer in the New York Division of the Federal Highway Administration. Some of them have been installed in New York City, as part of the city's efforts to reduce pedestrian accidents.

Roundabout success

The roundabout has shown it can reduce severe crashes at four-way, four-lane intersections up to 80%, McDevitt said, because it forces all traffic into a counterclockwise pattern with established exit points.

The "road diet" creates a center lane with yellow lines on each side, which sets up safer turns off a three-to-four-lane road, and at crosswalks provides "safe havens" for pedestrians. This does reduce the number of driving lanes by one, however.

Sharp right angles at intersections (vs. gently curved roadway that cars can drive through at higher speeds) not only slow the turning vehicles but shorten the length of pedestrian crosswalks.

What if the driver and pedestrian are out of sight of each other? A student at Monclair (NJ) State University, Aviv Butvinik, took first place in the contest, for his proposal covering a pedestrian crossing at the top of a hill, where an approaching car was out of pedestrian sight. A pole-mounted sensor aimed downhill would identify the car and flash a warning signal to pedestrians about to cross. The inspiration was an actual accident, he said.

Lighting the crosswalks, changing signaling, and building lights into the pavement were among the trials. But a clear understanding of when to stop and when to cross meant education was necessary, as they were not totally intuitive.

One alternative traffic signal that was successful with knowledgeable pedestrians and drivers has two side-by-side lights on top, one underneath. No-lights-on means drivers go. Lower light flashes yellow, then turns steady yellow to indicate cars should be stopping. Both upper lights then turn steady red to indicate cars should be stopped, and they are accompanied by a "walk" signal for pedestrians. Red lights wig-wag (flash alternately) to indicate walk period is ending, and they extinguish—no lights—for driving to resume. 

Additional signals that have been successful are a numerical countdown for the pedestrian's walk period (when it reaches "1," the walk interval is just about to end), and "wig-wag" beacons (pedestrian-activated) with yield signs.

Despite the fact that most fatalities occur at locations other than intersections, there is a significant percentage of fatalities, along with injuries, at intersections. So changes in signaling also can contribute to safety, McDevitt said. Another of the more successful were "pedestrian lead" systems, in which the pedestrian gets a head start of at least three seconds before turning drivers can go. This lead time puts the pedestrians in plain view of the turning drivers, so they can give the pedestrians a clear path.

NYC walk rate high

In New York City, 67% of people get to work by walking, cycling, taking public transportation, or using some combination of those modes. And about 52% of the approximately 250-300 auto traffic deaths per year are pedestrian fatalities. That's not surprising in a city with cars and trucks clogging streets and pedestrians in some areas crossing mid-street almost as often as at marked crosswalks.

The city has adopted Vision Zero, the multi-step national program operated locally, to reduce all auto accidents and pedestrian injuries—and fatalities in particular. Vision Zero includes legislation—headed by lowered vehicular speed limits—and enforcement to save pedestrian lives.

"But we can't 'summons' our way out" of the problem", said Thomas Chan, Chief of the NYC Police Department's Transportation Bureau, who is responsible for Vision Zero enforcement. He said public education is key, ranging from work with school administrators, senior centers, and other community organization.

Street design is another important part of NYC's Vision Zero picture, and because so many pedestrians cross mid-block the city is putting some crosswalks at seemingly more convenient locations—not necessarily at intersections.

Pedestrian-detection improvements

Vehicle engineering has helped reduce the number of driver and passenger fatalities dramatically, but when "soft tissue collides with steel," that means that accident avoidance may be the only way to prevent fatalities and/or severe injuries.

Volvo's Adam Kopstein, Manager North American Safety and Compliance, told the conference that the company's pre-collision detection with full auto-braking, uses LIDAR (laser enhanced radar) and for confirmation, a high-resolution camera with computer analysis of the image. The system was introduced to detect pedestrians in 2010, and in 2012 an upgrade for detection in darkness became available. A new version for detecting cyclists was introduced late last year, also with full auto-braking.

The detection/confirmation range should mean a full stop at speeds of up to 50 km/h (30 mph) and injury mitigation from higher speeds. The 2015 Hyundai Genesis has a less-defined detection system, using the adaptive cruise control radar sensor and the lane-departure-warning camera. But it is engineered to provide full auto-braking from speeds as high as 80 km/h (50 mph).

Kopstein pointed out that although an auto-braking system can reduce the damage and in some cases prevent it, the pre-collision warning, lane-keep assist, blind spot identification, automatic high beams, etc. are all part of the Volvo package for normal driving. Rearview cameras, although widely available already, are required by NHTSA in all new cars by 2018.

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