Medians (access management)

What are medians?

A median is a barrier between opposing lanes of auto traffic (see Table 1). Gaps in the median allow people to drive onto and off of a street and to make U-turns. Engineers refer to medians as "access management," which also includes driveway design and placement.

Streets featuring medians in Portland include large segments of SW Macadam Avenue, NE Martin Luther King Jr. Boulevard, and SE Powell Boulevard.

Medians support safety and local businesses

When installed as part of a toolkit of street design elements, medians can improve safety and support nearby businesses. Portland crash data indicate that multilane streets with medians experience crash rates that are 40% lower relative to similar streets lacking medians. National data mirror these local safety benefits, and also indicate that businesses do as well or better following median installation.

Table 1. Illustrations of a street with no median (left) and a median and other safety tools (right). 

Example street: No median	Example street: Median with other safety tools

Safety impact

Medians make streets safer for all people

Street segments with medians in Portland experience significantly lower crash rates relative to similar streets lacking medians. As Figures 1 and 2 show, the rate of deadly and serious injury crashes is 38% lower on Portland street segments with medians, while the overall crash rate is 40% lower.

Portland’s experience with medians is backed by national findings. The Federal Highway Administration (FHWA) notes that medians may reduce crashes involving people walking by 46% and those involving people driving by 39%.

The Federal Highway Administration explains the crash reduction effect of medians by pointing to the following impacts:

• Reduce conflict points for people driving by helping people make turns safely
• Provide people walking with a safe place to stop at the midpoint of a street before crossing the remaining distance
• Enhance visibility of crosswalks, particularly at unsignalized crosswalks
• Can support safe driving speeds approaching crosswalks
• Provide space for safety signage

In addition to enhancing safety, medians can make streets more attractive by providing a place to plant trees or other vegetation. While visibility can be a concern when adding vegetation, a Washington Department of Transportation study of 13 major urban arterials found that the presence of small trees in medians had no significant effect on crash rates.

Economic results

Generally positive experiences from business owners and customers

Studies have found that medians generally have neutral to positive economic effects on local businesses. 

Federal Highway Administration report (2024)

A Federal Highway Administration report found that access management projects—like adding medians—typically do not harm businesses. In many cases, they help. Customers adapt to new travel patterns, and improved safety and street design can attract more shoppers. Most business owners say the impacts were less than expected and often limited to construction. Key takeaways include:

• Business closures do not increase after access changes. A multistate study found turnover rates stayed the same or were lower than surrounding areas.
• Sales often stay the same or improve. In Utah, sales rose by 32% after raised medians were added. In Iowa, 65% of businesses reported stable or increased sales.
• Some businesses report more customers and better access. In New York City, retail sales at one location doubled three years after adding bike lanes and a tree-lined median.
• Property values tend to hold steady or rise. Studies in Kansas, Minnesota, and Texas found no long-term decline in value.
• Customers and truck drivers report safer, smoother trips. In Iowa, Texas, and Florida, most customers said the projects made travel quicker, easier, and safer. 

Well-planned access project can benefit both businesses and travelers. 

Texas Transportation Institute report (2013)

Research indicates that the economic effects of medians vary but are largely positive. For example, a Texas Transportation Institute study found that gas stations and auto-repair shops experienced slight declines in gross sales, but concluded that “in almost all cases, employment increased in businesses surveyed” following installation of a raised median (see Table 2). 

Oregon Department of Transportation and Oregon Transportation Research and Education Consortium report (2013)

An Oregon Department of Transportation and Oregon Transportation Research and Education Consortium report summarized a number of studies examining the economic impact of medians. Among the findings:

• Ivey, Harris and Walls Inc. (1995) surveyed business operators following construction of medians, and found that more than half of the business owners reported no change or an increase in their sales after the median construction.
• Frawley and Eisele (1998) found that between 16 and 22% of business owners believed that their gross sales decreased following median construction. Eisele and Frawley (1999) later determined that those same corridors actually experienced an 18% increase in property values following median construction.
• Stover & Koepke (2000) found that 68% of business owners who participated in a survey reported little or no economic impact to their businesses following median construction, although 27% reported some type of loss following the closure of select median openings.