Click for next page ( 61


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 60
60 basis has been accepted, then the existing vehicle-based war- One of the pedestrian characteristics collected during the rants can be used to derive comparable warrants for crossing field studies was the time for pedestrians to cross to the mid- pedestrians. The net effect of the proposed revisions is as fol- dle of the street or median and then to the other side of the lows: (1) the pedestrian warrant will be slightly easier to meet street. Using the distances being crossed, the walking speeds of with lower pedestrian volumes on streets with high vehicle the pedestrians were determined. To permit comparisons with volumes, and (2) the pedestrian warrant will be slightly more other studies, the data were grouped to reflect the following: difficult to meet on streets with low vehicle volumes. In addition to traffic signal warrant revisions, the research Younger--includes pedestrians between the ages of 13 and team identified two other MUTCD sections that could be 60 and revised. The first revision is a minor addition to an enumer- Older--includes pedestrians older than 60. ated list of alternatives to traffic control signals (MUTCD Section 4B.04). The recommended addition suggests the use The following conclusions were developed for walking of median refuge islands or curb extensions as alternatives to speed: traffic control signals that could improve pedestrian safety. This first revision was accepted by the NCUTCD in January The 15th percentile walking speed for younger pedestrians 2006 and could appear in future MUTCD versions (after is 3.77 ft/s (1.15 m/s) (sample size of 2,335), and the 15th additional reviews by others). The second recommended percentile walking speed for older pedestrians is 3.03 ft/s revision is the inclusion of a new type of highway traffic sig- (0.92 m/s) (sample size of 106). nal in the MUTCD called "pedestrian beacon." This revision The older pedestrian groups (male, female, and both) had was endorsed by the Signal Technical Committee in January 15th percentile walking speeds that differed statistically from 2006 and will go to sponsors during the Spring of 2006. The the 15th percentile walking speeds of the younger pedestrians. Signal Technical Committee will respond to sponsors' com- Two studies with databases that contain more than 2,000 ments during their Summer 2006 meeting. The pedestrian pedestrian crossings are the 1996 Knoblauch et al. study (14) beacon represents devices that this study found to be most (data collected in 1993) and this TCRP/NCHRP study. The effective on high-volume, high-speed roadways. data collected in 2003 for the TCRP/NCHRP study identified a slower walking speed for the younger group--(3.77 ft/s Recommendation [1.15 m/s] as compared with 4.02 ft/s [1.23 m/s])--than found in the 1993 data collected for the Knoblauch et al. study. The research team recommends a continuing dialog with the When both older pedestrians and younger pedestrians are appropriate NCUTCD technical committees in order to encour- considered using the Knoblauch et al. data (sample size of age adoption of these recommended revisions to the MUTCD. 4,459), the 15th percentile value of 3.53 ft/s (1.08 m/s) was To change the MUTCD, it may be necessary for such a dialog to determined. continue beyond the duration of this study. Members of the research team have already presented proposed MUTCD revi- sions, with some elements received favorably and other elements Recommendation requiring considerably more discussion and debate. Comparing the findings from this TCRP/NCHRP study with previous work resulted in the following recommendations: Walking Speed Summary 3.5 ft/s (1.1 m/s) walking speed for general population and 3.0 ft/s (0.9 m/s) walking speed for older or less able Pedestrians have a wide range of needs and abilities. The population. MUTCD includes a walking speed of 4.0 ft/s (1.2 m/s) for cal- culating pedestrian clearance intervals for traffic signals. It These values are being considered for the upcoming also includes a comment that, where pedestrians walk more revision to the MUTCD. slowly than normal or pedestrians in wheelchairs routinely use the crosswalk, a walking speed of less than 4.0 ft/s (1.2 m/s) should be considered in determining the pedestrian Motorist Compliance clearance times. Other research studies have identified pedes- Summary trian walking speeds ranging from 2.2 to 4.3 ft/s (0.6 to 1.3 m/s). In 2002, the U.S. Access Board used the guidelines pre- The research team chose motorist compliance (yielding or pared by the Public Rights-of-Way Access Advisory Commit- stopping where required) as the primary measure of effec- tee and recommended a universal maximum pedestrian tiveness for engineering treatments at unsignalized roadway walking speed of 3.0 ft/s (0.9 m/s) (57). crossings. Motorist compliance data were collected at 42

OCR for page 60
61 study sites that included nine different types of pedestrian The number of lanes being crossed influences the effec- crossing treatments. In addition to collecting motorist yield- tiveness of the crossing treatment. All but one of the treat- ing behavior for general population pedestrians, the data col- ments on the two-lane roadways performed at a better than lection personnel also staged street crossings to ensure 75-percent compliance rate. On four-lane roadways, com- consistency among all sites as well as adequate sample sizes. pliance ranged from below 30 percent to 100 percent. The research team analyzed motorist compliance thoroughly The posted speed limit influences the effectiveness of the and used the findings to support development of the Guide- crossing treatment. Flags, refuge islands, and high-visibility lines for Pedestrian Crossing Treatments. Conclusions about markings all have higher compliance rates on lower-speed motorist compliance are as follows: roadways. On a 35-mph (55-km/h) roadway, the best com- pliance rate observed for a treatment not showing a red The crossing treatment affects motorist compliance. Those indication to the motorist was about 58 percent. Compli- treatments that show a red indication to the motorist have ance rates for the devices on 25-mph (40-km/h) streets all a statistically significant different compliance rate from were above 60 percent. Compliance rates were as low as 15 devices that do not show a red indication. These red signal percent for streets with a 35-mph (55-km/h) speed limit. or beacon devices had compliance rates greater than 95 percent and included midblock signals, half signals, and Recommendation HAWK signal beacons. Nearly all the red signal or beacon treatments evaluated were used on busy, high-speed arte- The research team recommends the addition of red signal rial streets. Pedestrian crossing flags and in-street crossing or beacon devices to the engineer's alternative for pedestrian signs also were effective in prompting motorist yielding, crossings. The study results indicated that all red signal or achieving 65 and 87 percent compliance, respectively. beacon devices prompted high levels of motorist compliance However, most of these crossing treatments were installed on high-volume, high-speed streets; however, only a traffic on lower-volume, two-lane roadways. signal is currently recognized in the MUTCD, and the current The measured motorist compliance for many crossing pedestrian signal warrant is very difficult to meet. Thus, in the treatments varied considerably among sites. For example, current situation, engineers cannot easily use those traffic treatments in the "active when present" and "enhanced control devices that appear to be most effective for pedestri- and/or high-visibility" categories have a wide range of ans on wide, high-speed streets. As indicated previously in the compliance rates as shown in Figure 24. In fact, a statistical signal warrant recommendations, the research team recom- analysis could find no significant differences between many mends the inclusion of a new type of highway traffic signal (a of the crossing treatments, even though the difference in "pedestrian beacon") in the MUTCD. These pedestrian bea- average compliance rates appeared to be practically signif- cons would have different signal operation modes than tradi- icant (30 to 40 percent greater). The research team con- tional traffic control signals and would include the red signal cluded that other factors (such as, roadway width, speed or beacon devices that this study found to be most effective limit, and street environment) affected compliance rates. on high-volume, high-speed roadways.