Medians and pedestrian crossing islands in urban and suburban areas

Midblock locations, where vehicle travel speeds are higher, account for more than 70% of pedestrian fatalities. More than 80% of pedestrians die when hit by vehicles traveling at 40 mph or faster while less than 10% die when hit at 20 mph or less (Federal Highway Administration, 2012).

Installing raised channelization or medians on approaches to multi‐lane intersections has been shown to an effective pedestrian safety countermeasure in areas where pedestrians access a transit stop or other clear origins/destinations across from each other. Raised medians (or refuge areas) should be considered in curbed sections of multi‐lane roadways in urban and suburban areas, particularly in areas where there are mixtures of significant pedestrian and vehicle traffic (more than 12,000 Average Daily Traffic) and intermediate or high travel speeds. Medians/refuge islands should be at least 4 feet wide (preferably 8 feet wide to accommodate pedestrian comfort and safety) and of adequate length to allow the anticipated number of pedestrians to stand and wait for gaps in traffic before crossing the second half of the street (Federal Highway Administration, 2012).

Shultz et al. (2011) used a hierarchical Bayesian model to analyze the effectiveness of raised median installations on overall and severe crash frequency in the state of Utah by determining the effect each has on crash and severe crash frequency. Several sites where raised medians have been installed in the last 10 years were evaluated using available crash data. The results of the study showed that the installation of a raised median is an effective technique to reduce the overall crash frequency and severe crash frequency on Utah roadways. Overall crash frequency decreased by 25% while severe crash frequency decreased by 36% along corridors where raised medians were installed.

Elvik and Vaa (2004) found that providing a raised median on principal arterial roads in urban areas reduced all crashes by 39%, reduced serious and minor injury crashes on principal arterial roads in urban areas by 22%, reduced serious and minor injury crashes on principal arterial roads in rural areas by 12%, and reduced property damage only crashes on principal arterial roads in rural areas by 18%.

Zegeer et al. (2005) conducted a study to determine whether marked crosswalks at uncontrolled locations were safer than unmarked crosswalks under various traffic and roadway conditions. The study involved an analysis of 5 years of pedestrian crashes at 1,000 marked crosswalks and 1,000 matched unmarked comparison sites. No sites in this study had traffic signal or stop signs on the approaches. Detailed data were collected on traffic volume, pedestrian exposure, number of lanes, median type, speed limit, and other site variables. The authors found that raised medians provided significantly lower pedestrian crash rates on multilane roads, compared to roads with no raised median.

Scope of the Problem

• U.S. Department of Transportation (2012). Proven Safety Countermeasures, Medians and Pedestrian Crossing Islands in Urban and Suburban Areas. U.S. Department of Transportation Federal Highway Administration. Report No. FHWA-SA-12-011. Retrieved from http://safety.fhwa.dot.gov/provencountermeasures/fhwa_sa_12_011.htm

Evidence

• Schultz, G., Thurgood, D., Olsen, A., Reese, C.S. (2011) Analyzing Raised Median Safety Impacts Using Bayesian Methods. Presented at the 90th Meeting of the Transportation Research Board, Washington, D.C. Retrieved from http://www.cmfclearinghouse.org/study_detail.cfm?stid=213
• Elvik, R. and Vaa, T. (2004), Handbook of Road Safety Measures. Oxford, United Kingdom, Elsevier.
• Zegeer, C. V., Stewart, J. R., Huang, H. H., Lagerwey, P.A., John Feaganes, J. & Campbell, B.J. (2005) Safety Effects of Marked versus Unmarked Crosswalks at Uncontrolled Locations: Final Report and Recommended Guidelines, University of North Carolina, Highway Safety Research Center, Chapel Hill, NC Report No. FHWA–HRT–04–100. Retrieved from http://www.fhwa.dot.gov/publications/research/safety/04100/04100.pdf