Crosswalks, Uncontrolled

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Crosswalks, Uncontrolled

Uncontrolled crosswalks are marked crosswalks where no traffic controls such as a stop sign or signal exist. Such markings have become much rarer since the early 1970's, as traffic engineers have systematically removed marked crosswalks from uncontrolled locations, believing the markings provide a "false sense of security." Recent studies suggest the story is far more complicated.

Background

Livable streets guru Dan Burden observes that able-bodied pedestrians will not generally walk more than approximately 150 feet to reach a controlled crosswalk. Along corridors where controlled intersections are farther apart than 300 feet, this means a lot of pedestrians will be crossing illegally mid-block, or at uncontrolled intersections, such as where a 2-lane residential street intersects with a 4-lane arterial.

Engineers are appropriately cautious about placing a crosswalk in any uncontrolled location, especially if the street is a multi-lane collector. Unfortunately, engineers have erred in the other direction, removing crosswalks and pronouncing pedestrians safer as a result.

"False Sense of Security" Theory
For many years, where and when to paint a crosswalk in the U.S. has been decided on the basis of popular assumptions from a single study, published in 1972. [1] The so-called "Herms Study" of crosswalks at uncontrolled intersections in San Diego, California, found there were more pedestrians struck (per person crossing) at uncontrolled intersections where a crosswalk was marked than in those left unmarked. However, Herms did not account for the fact that markings were probably provided at precisely htose locations where pedestrian;/vehicle conflicts were an issue.

But neither did the study conclude all marked crosswalks are unsafe. Yet, that is the common misinterpretation by the traffic engineering profession. Rather unfortunately, Herms also speculated that marked crosswalks at uncontrolled intersections may give a "false sense of security" to pedestrians using them. On the basis of this "theory," engineers have been removing marked crosswalks for decades, and failing to provide new ones in critical locations.

Debunking the "False Sense of Security" Theory

adamsxwalknw.jpgThe Herms Study's theory of pedestrian behavior has been debunked by more recent studies. Knoblach et al. [2] found that pedestrians exhibit more, not less caution, in a crossing location after a crosswalk has been marked. (The comparison was at the same location, before and after the crosswalk was marked.) For their part, drivers were found to slow down slightly when approaching the marked crosswalks. This does not mean it is safe to provide a crosswalk anywhere, some locations are too dangerous. Rather, it indicates that crosswalk markings, appropriate signage, and other safety measures aimed at warming motorists should not be avoided on the theory that they induce a"fase sense of security" in pedestrians. Advocates for pedestrian safety are justifiably weary of hearing this phrase, especially given its shaky empirical underpinnings.

To clarify once and for all where crosswalks may be marked, the Federal Department of Transportation conducted a study which examined thousands of pedestrian crashes in all 50 states and set guidelines for installing marked crosswalks. This so-called Zegeer Study [3] is the most thorough of its kind ever conducted. Importantly, it controlled for pedestrian volume and crosswalk location and has a more than adequate sample size, all serious flaws of earlier studies.

New Federal Guidelines for Crosswalks

The federal guidelines resulting from the Zegeer Study indicate that, as an example, a marked crosswalk is safe to provide for a 2-lane road if the speed limit does not exceed 40 mph and traffic volumes fall below 12,000 daily trips. This assumes there are no unusual circumstances, such as a blind curve, a visibility problem, or a high volume of large trucks. If any of these conditions occur, a marked crosswalk alone provides no safety advantage. The authors emphasize that, "in most cases, marked crosswalks are best used in combination with other treatments (e.g., curb extensions, raised crossing islands, traffic signals, roadway narrowing, enhanced overhead lighting, traffic calming measures, etc.). Think of marked crosswalks as one option in a progression of design treatments. If one treatment does not adequately accomplish the task, then move on to the next one. Failure of one particular treatment is not a license to give up and do nothing. In all cases, the final design must accomplish the goal of getting pedestrians across the road safely."

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REFERENCES

Each source is referred to by the same number every time it is cited. Please keep citation style consistent.
[1] Herms, Bruce. 1972. Pedestrian Crosswalk Study: Accidents in Painted and Unpainted Crosswalks,Transportation Research Record No. 406, Transportation Research Board, Washington, DC.
[2] Knoblauch, R.L., Nitzburg, M., and Seifert, R.F., 1999. Pedestrian Crosswalk Case Studies, Federal Highway Administration, Washington, DC.
[3] Zegeer, Charles, J. Richard Stewart, Herman H. Huang, and Peter A. Lagerwey. 2002. Safety Effects of Marked vs. Unmarked Crosswalks at Uncontrolled Locations, Federal Highway Administration, Washington, DC.

PICTURE REFERENCES

Pictures are cited in the order they appear above. Please keep citation style consistent.
[1] Courtesy of Dan Gallagher, WalkSanDiego
[2] Courtesy of Andy Hamilton, WalkSanDiego

FURTHER READING