Wayne State professor and chair of the department of Civil and Environmental Engineering says the city can remove thirty percent of its traffic signals

DETROIT- The chair of the department of Civil and Environmental Engineering at Wayne State University's College of Engineering recently conducted a study that resulted in the recommendation that the city of Detroit remove 30 percent of its traffic signals to save money and improve traffic flow.

Professor Joseph Hummer teamed up with doctoral student Michael Schrader to follow up on the city's recent effort to remove unnecessary traffic signals in the downtown and Midtown areas. Hummer explains, "We saw this as a way that the city could save thousands or millions of dollars in signal operation costs per year while also saving driver time and collisions."

The results from their study suggest that 30 percent - almost 500 - of the signals throughout the rest of the city "can be removed and replaced with either two-way or four-way stop control while still maintaining adequate levels of service for all approaches, resulting in savings of $460,000 to $3,700,000 annually in operating costs." Cities that, like Detroit, have lost population in recent years could also strengthen their efforts to 'right-size' their infrastructure by conducting their own signal removal studies.

According to the U.S. Department of Transportation, annual signal operating and maintenance costs can range from $1,000 to $8,000 per signal. Additionally, previous research has found a correlation between the removal of signals and a decrease in auto crashes.

One of the signals that Schrader and Hummer say the city should consider removing is located at the intersection of Charlevoix and Lakeview, on the city's east side. Noting that the intersection is devoid of activity, they suggest that replacing the signal with a two-way stop would likely save money and better manage traffic flow.

Interestingly, the study found a lack of correlation between the number of signals that should be considered for removal and the population drop in Detroit, which is 61 percent since 1950. Schrader and Hummer suggest that this is due to Detroit's high levels of "pass-through" traffic, where vehicles coming from outside of the city drive through city neighborhoods to get downtown or to another location outside of the city.

Schrader and Hummer have submitted their paper for publication to the journal of Public Works Management and Policy.

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Contact: Melissa Ellison
Voice: 313-577-3853
Email: melissa.ellison@wayne.edu