Case Study No. 36
Salt Lake City, Utah
Prepared by Laurie Actman, Patrick McMahon, and Henry Renski, University of North Carolina Highway Safety Research Center, and Kevin Young, Salt Lake City, UT Division of Transportation. 2012 updates by Dan Bergenthal, Salt Lake City Transportation Division.
The Salt Lake City Division of Transportation frequently received calls from pedestrians concerned about ladder style crosswalks being slippery on wet and icy days. The marked surfaces of ladder crosswalks can be slippery when wet, especially as the crosswalk surface wears smooth. Complaints about the crosswalks often came from school crossing guards because many of the ladder crosswalks were near schools.
The double-ladder crosswalk up close.
After listening to the concerns raised by the crossing guards, Salt Lake City Division of Transportation engineers brainstormed and then tried an experiment with an alternate design. This new design eliminates the markings from the middle third of the crosswalk. For example, if the crosswalk is 12 ft wide, the dimensions would be 4 ft of white crossbar, 4 ft of smooth pavement, then 4 ft of additional crossbar. This design is called a "double ladder" crosswalk. The double ladder crosswalk maintains the same visual appearance of the single ladder crosswalk from the driver's point of view, but allows pedestrians to walk in the paved surface between the two ladders of the crosswalk. It is used only at mid-block locations and around schools.
The double-ladder crosswalk from a distance.
The separation between the longitudinal lines does not decrease the advance visibility of the crosswalk for motorists. Salt Lake City tests have shown that the double ladder crosswalk appears the same to a motorist as a standard ladder crosswalk until the motorist is within 150 ft of the crosswalk. By the time the motorist notices the difference, they are already aware of the existence of the crosswalk.
The separation between the longitudinal lines of the double ladder crosswalk provides pedestrians an unmarked area to walk during those times when the crosswalk is wet and the potential for a pedestrian to slip is increased. The separation removes the hazard of the slippery surface at the crosswalk and improves the safety for pedestrians using the crosswalk.
Salt Lake City has had great success with the use of double ladder crosswalks. The new marking process is less expensive and does not take more time than previous crosswalk installations. Use of the double ladder design began in the mid-1990s. Since their initial test and adoption, city crews have been routinely replacing worn crosswalks of the old style with the new design at appropriate locations on repaving projects and newly constructed roads. The majority of double ladder crosswalks can be found in the downtown area and in school zones.
Comments received from the traveling public regarding double ladder crosswalks have been universally favorable. School crossing guards like the new crosswalk design and have reported feeling that they are less likely to slip during wet and icy weather.
Through the use of double-ladder crosswalks, Salt Lake City's Division of Transportation found a creative way to successfully maintain pedestrian safety at intersections without compromising the ability of pedestrians to cross safely in wet pavement conditions.
Transportation Planning Engineer
Salt Lake City Division of Transportation
349 S. 200 East, Suite 450
Salt Lake City, UT 84114-5502
Phone: (801) 535-6630