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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
This magazine is an archived publication and may contain dated technical, contact, and link information.
|Publication Number: FHWA-HRT-05-001 Vol. 69 No. 3 Date: November/December 2005|
Publication Number: FHWA-HRT-05-001 Vol. 69 No. 3
Date: November/December 2005
FHWA is evaluating new technologies and techniques to determine how well they improve safety.
|(Above) At test sites like this one in Miami, FL, FHWA is evaluating new safety treatments that may help motorists and pedestrians become more aware of each other. Although the intersection includes a pedestrian refuge area, the continuous right turn lane can prove hazardous for pedestrians. At this site, researchers will install a sign directing turning traffic to yield to pedestrians. Photo: Dan Nabors, BMI-SG.|
Every year in the United States nearly 5,000 pedestrians are killed and approximately 70,000 are injured. These pedestrian deaths represent nearly 11 percent of all roadway fatalities nationwide. Although the long-term trend indicates that pedestrian fatalities have decreased from a high of 8,096 in 1979 to a low of 4,749 in 2003, the Federal Highway Administration (FHWA) and State departments of transportation (DOTs) recognize that pedestrians are still being killed or seriously injured on the Nation's roadways.
To help further reduce the fatalities, FHWA set an ambitious goal of reducing pedestrian fatalities by 10 percent by 2008. To achieve this goal, FHWA is looking for new strategies and technologies to improve pedestrian safety and is evaluating some new options as part of a 6-year project known as the Pedestrian Safety Countermeasure Deployment Project.
The goal of the Pedestrian Safety Countermeasure Deployment Project, scheduled for completion in December 2006, is to evaluate the effectiveness of various pedestrian safety treatments, or countermeasures, in three cities: Las Vegas, NV; Miami, FL; and San Francisco, CA. The findings from these studies then could be applied to other cities across the country.
During phase one of the two-phase study, three teams of researchers documented the pedestrian incident problems in each of the cities to identify the optimal locations to install safety countermeasures. The researchers first collected data on all fatal and nonfatal crashes involving pedestrians and then mapped them using geographic information system (GIS) technology. "The 'zone analysis' method that we are using for this study was developed [by the National Highway Traffic Safety Administration] to identify high density collision locations," says Dr. David Ragland, director of the Traffic Safety Center (www.tsc.berkeley.edu/html/home.html) at the University of California-Berkeley (UC Berkeley). "This method helps us to focus resources on locations with a high promise for collision and injury reduction."
Phase two of the study is implementation, which is currently underway. During implementation, teams are deploying countermeasures at specific sites in the zones they identified during phase one. For the Miami and San Francisco studies, the researchers are treating one site at a time in a staged manner, so they can be sure that any change measured was caused by the countermeasure. Because the other sites along the corridor are untreated, they serve as controls for comparisons to the treated sites.
"We felt that conducting the study in this staged manner would provide better data than the usual before-and-after study," says Ron Van Houten, chair of the Transportation Research Board's Pedestrian Committee, who has been coordinating the Miami portion of the research through the University of Florida. "The problem with the typical before-and-after study is that in the after period other factors can change that affect results. In our case, we collected data at the other untreated sites as well, so we had these control sites to compare to the sites where we implemented treatments. We treated the control sites as well at a later time, which served to replicate the results obtained at the earlier sites."
|At locations with high volumes of pedestrians, like this one in San Francisco's Chinatown neighborhood, traffic signals may be programmed for an exclusive pedestrian phase, also known as a pedestrian scramble. All traffic is stopped, and pedestrians are given a walk phase on all four crosswalks, so they may cross the intersection in any direction, including diagonally. Targeted educational material is essential in advance if such a system is to work properly.|
The researchers are evaluating a wide range of countermeasures. "Some [measures] focus on clarifying rules for who has the right-of-way, [while others provide] pedestrians with more exclusive space by the use of medians and extended curbs," says Ragland from UC Berkeley. "Another approach is to increase the awareness of potential conflicts for both pedestrians and drivers, and for this, ITS [intelligent transportation system] technologies can be very helpful."
Some countermeasures the researchers are evaluating include low-technology techniques, such as signs that are used in new ways, like in-roadway knockdown signs. "Sometimes technology isn't necessarily the only answer," says W. Scott Wainwright, a highway engineer at FHWA who helped to define the standards for traffic control devices in the most recent Manual on Uniform Traffic Control Devices (MUTCD). "Sometimes it's just a matter of applying existing technologies in a better way. But if new technologies come along that can help reduce crashes or even make mobility more convenient for pedestrians, then that's worth investigating."
Although the project is still underway, the researchers are finding that some of the more promising ITS technologies in the study include pedestrian signals that count down the time available for crossing, roadway signs that light up to warn motorists of the presence of pedestrians, and pedestrian-activated crosswalk illumination.
Researchers are evaluating smart nighttime lighting in Las Vegas and Miami to determine if using high-intensity light-emitting diode (LED) lighting above crosswalks helps alert motorists to the presence of pedestrians. The study has shown that a sudden increase in lighting intensity alerts motorists that pedestrians are in the crosswalk more effectively than lighting with a continuous intensity. The high-intensity lighting remains lit only while pedestrians are in the crosswalk.
The lighting is activated either when a pedestrian pushes the button to cross or when an automated device detects the pedestrian. "Special lighting that only comes on when a pedestrian is present provides an effective signal to the driver at night," says Van Houten, noting that nighttime crashes account for a high percentage of pedestrian fatalities. "It's also cost effective from an energy standpoint because you can use very bright lighting only when it is necessary."
|Countdown pedestrian signals like this one have proven popular with the public because they take the guesswork out of how much time a pedestrian has to cross or finish crossing the street.|
|Pedestrian countdown signals and animated eye displays are among the safety treatments incorporated into the latest edition of the MUTCD, shown here.|
In-roadway warning lights (IRWLs) also help increase awareness of pedestrians by illuminating the crosswalk from the pavement. "More IRWLs are being [installed] with LED technology to try to reduce the cost," says FHWA's Wainwright. "With LEDs, because they require less electrical power, there are systems being developed that are battery operated and use solar power that recharges the battery. This technology seems to get even better as time goes on, and it should bring the cost down so cities could use them at more crosswalks." FHWA is considering providing additional funding to Las Vegas to evaluate IRWLs as a part of the pedestrian safety countermeasures study. For more information on IRWLs, see "Seeing Crosswalks in a New Light" in the January/February 2004 issue of PUBLIC ROADS.
|A wirelessly activated solar-powered in-roadway warning light, like the one shown here, can provide energy-efficient, in-pavement lighting for crosswalks.|
Researchers in all three cities are evaluating pedestrian countdown signals, which show pedestrians exactly how much time they have to cross a street before the light will change. FHWA already has incorporated this technology into MUTCD standards. "The feedback from pedestrians has been really positive, and the studies show positive impacts as well," Wainwright says. "The studies have found that the percentage of pedestrians making what's called a 'successful crossing,' meaning they got to the far side of the crosswalk before the light changed, is considerably larger with countdown signals."
He adds that pedestrians also can make better decisions about whether to start crossing based on the time display. "Particularly, we found [that] someone who is halfway across the street and sees the time winding down will speed up to get across faster," Wainwright says.
These signals also may encourage more pedestrians to use the pushbutton rather than jaywalk. "For countdown timers, our study's preliminary data seems to be showing that when you put them in, more pedestrians push the button," says Van Houten. "The more information you give people, the more reason there is to push the button."
The same holds true for pushbuttons that provide feedback to pedestrians. "We know that if the button lights up like an elevator button or sounds a tone after it's pushed, then significantly more pedestrians will push the button, and significantly more will also wait to cross because they can see the pushbutton has been activated," Van Houten says. "So for a very little bit of cost, you get a modest improvement."
Animated or "roving" eye displays on pedestrian signals are being evaluated in Las Vegas and San Francisco to determine whether they encourage pedestrians to watch for vehicles turning into the crosswalk from another street. During the walk indication, the animated eyes scan from side to side, reminding pedestrians to look both ways. Animated eye displays for pedestrian signals also have been incorporated into MUTCD standards.
LED animated eyes also may be used to warn motorists of crossing pedestrians. These displays are mounted overhead before a marked but unsignalized crosswalk to alert drivers that a pedestrian is crossing. Pedestrians may activate the sign using the pushbutton, or the system may be automated to detect pedestrians. The animated eye display either looks left, right, or both ways, depending on where pedestrians are crossing. The research teams in Las Vegas and Miami are evaluating whether these animated eye displays help alert motorists to the presence of pedestrians in crosswalks.
Lighting the Way to Pedestrian Safety
For more than a decade, California municipalities have been using in-roadway warning lights (IRWLs, also known as in-pavement flashers and up-lights) as an option to improve pedestrian safety at uncontrolled crosswalks. After San Francisco installed lighted crosswalks at selected school crossings, residents requested that they be put at all of them. As quoted in the San Francisco Examiner, former Mayor Willie Brown said, "[We'll] figure out some way to fund them."
IRWL systems offer a number of benefits. First, they activate when a pedestrian is crossing, enabling drivers to learn to associate them with a need to yield or slow down for pedestrians in crosswalks. Second, IRWLs delineate the crosswalk and draw the driver's attention to the roadway. Further, they provide a warning for drivers in the left lanes of a four-lane road, even when the driver's view of the curbside lane and crosswalk may be blocked by other vehicles. Finally, IRWLs can help minimize capital expenses compared to other safety measures that serve the same purpose.
A number of studies have shown that IRWL systems can improve safety for pedestrians. According to a recent study for the New Jersey Department of Transportation, Pedestrian Crosswalk Safety: Evaluating In-Pavement, Flashing Warning Lights, by the Lighting Research Center at the Rensselaer Polytechnic Institute, the use of IRWL systems increases vehicular yielding to pedestrians and decreases crosswalk approach speeds. A recent FHWA-sponsored study, The Effects on Safety of In-Roadway Warning Lights at Crosswalks: Novelty or Longevity?, reported similar results for driver yielding.
There are, however, some issues localities should consider before implementing IRWL systems. Some traffic engineers are concerned that the small IRWL lights may not create attention-getting visibility during the brightest part of the day, especially when backlit by a setting sun. Maintenance is another concern, especially given the lack of ongoing funding to support grant-based installations. The Intelligent Transportation System Unit Cost Database estimates annual maintenance costs at 10 percent of the initial system cost.
Nevertheless, many cities remain enthusiastic about IRWLs as one tool in the traffic engineer's toolbox for addressing pedestrian safety concerns at uncontrolled crosswalks. "I think you're going to continue to see more use of IRWLs," says Gerry Meis, chief of the Office of Signs, Markings, and Permits at the California Department of Transportation (Caltrans) and a longtime participant in IRWL discussions at Caltrans.
For more information, see Resource Guide, Regional Pedestrian Committee, Oakland, CA, Metropolitan Transportation Commission, www.mtc.ca.gov, or see www.spotdevices.net, or contact Thomas Burnham at 888-266-6728 or email@example.com.
by Thomas Burnham
In the arena of taking an existing device--a traffic sign--and using it in a new application, engineers are now installing what are known as "in-roadway knockdown signs" to alert drivers to pedestrian crossings. Recently added to the MUTCD, these signs remind approaching drivers that State law requires yielding to pedestrians.
In the past, placing signs in the middle of the road was not permitted because they represented fixed-object hazards. "But new technology has made it possible to fabricate signs from rubber-like material and mount them on flexible posts that bend over and bounce back into position if a vehicle accidentally hits them," Wainwright says. These signs are a direct and very visible reminder to motorists that they must yield to pedestrians in the crosswalk. All three cities are testing in-roadway knockdown signs.
Because many pedestrians do not push the crosswalk button, which both provides pedestrians with adequate time to cross and also can trigger a warning sign for motorists, engineers are evaluating technologies that can detect pedestrians automatically. "Pedestrian detection is an emerging technology," UC Berkeley's Ragland says. "If it works well, it can be used to activate pedestrian crossing signals for pedestrians and also to extend signal timing for a pedestrian who may be delayed in crossing. It also could warn drivers that a pedestrian is crossing, either through electronic signs, or possibly in the future, directly to the driver in a vehicle."
|This photo shows a pedestrian signal with animated or "roving" eyes. The eyes serve as a reminder to pedestrians to look out for traffic while they are crossing the street. FHWA's partners are installing animated eye signals like this one as part of its study of countermeasures to improve pedestrian safety.|
|This photo shows a pedestrian "roving" eyes display that is intended for drivers. The signal is hung over a pedestrian crossing, and when it turns on, the "roving" eyes remind drivers to watch out for pedestrians. The signal is activated by a pedestrian and indicates, by placement of the pedestrian on the sign (right or left), which direction the pedestrian is crossing from.|
Researchers in Las Vegas and San Francisco are evaluating whether the current technologies are reliable enough. "With respect to having pedestrians detected without having to push a button, there are some very promising technologies that aren't yet quite reliable enough," FHWA's Wainwright says. "In some cases you have to detect every pedestrian, and you have to be 100-percent reliable. At the same time, you don't want false calls when pedestrians aren't there."
Another concern is whether they are affordable. "The big thing we're hoping to see in the future is a cost-effective way of reliably detecting pedestrians without pushbuttons," says Van Houten. One way of doing that is through cameras, but those are typically expensive. "If we can automatically detect pedestrians crossing, not those passing by and not mistaking a vehicle for a pedestrian, then we're becoming more intelligent in monitoring pedestrians so we can alert the motorists."
An additional benefit of automated detection is that if a pedestrian leaves the area and decides to cross elsewhere, the pedestrian signal crossing time can be shortened so vehicular traffic is not delayed unnecessarily.
Until this study is complete at the end of 2006, the researchers will not be able to provide detailed evidence on the most promising techniques to improve pedestrian safety. In the meantime, however, local and State governments can begin to consider whether some of these treatments may be appropriate in their own cities and communities. The researchers selected the various countermeasures for use in the study based on a complete analysis of the safety problem, including the crash data for the location, the factors leading up to each crash, observed "unsafe" behavior of pedestrians and motorists, and assumptions made about each countermeasure and the impact they would likely have on the specific locations.
|In-roadway knockdown signs, such as this one installed near the Golden Gate Bridge in San Francisco, are placed in the crosswalk as a highly visible reminder to motorists to yield to pedestrians in the crosswalk. Made from flexible materials, the signs bounce back up if knocked down by a vehicle.|
As with any new traffic control device, engineers should carefully consider their road users and facilities before deciding on a particular treatment. "What works at one site may not work in another, because the roads and other characteristics are different," says Van Houten. "For example, Las Vegas has some very wide roads, while in Miami the roads tend to be narrower. This can be an issue because some pedestrian signs or signals are currently made in only a certain size, so they could be hard to read across a very wide road. "
|This photo of one of the test sites illustrates a typical problem for pedestrian crossings in Las Vegas, where roads tend to be wide, with little or no median, making it difficult and dangerous for pedestrians to cross.|
Local engineers must first evaluate the characteristics of a particular intersection or crossing area before selecting a treatment. "For any kind of traffic control device, you can't make generalizations that it will work well in any urban location, because in reality every place and every intersection is different," Wainwright says. "Traffic control devices have to be deployed based on engineering studies of individual locations. Every situation is different, and the engineer makes an assessment of the problems and alternatives for those traffic conditions." Also, because not all of the devices being evaluated are currently approved under the MUTCD, localities must obtain permission from FHWA to experiment before installing any unapproved devices.
Finally, pedestrians and motorists may initially be confused by a new treatment, so localities should make a special effort to educate community members about the use of any new treatments.
Tamara Redmon is manager of the pedestrian and bicyclist safety program for the FHWA Office of Safety. Redmon has worked for FHWA for more than 14 years, and she develops products and programs to help reduce pedestrian and bicyclist crashes, fatalities, and injuries. She holds a bachelor of science degree from Virginia Polytechnic Institute and State University and a master of science degree from Marymount University.
For more information on pedestrian safety, please visit http://safety.fhwa.dot.gov/ped_bike/.