COLUMBIA — The City Council voted unanimously Monday night to prepare an ordinance that would reduce residential speed limits from 30 to 25 mph throughout Columbia.
Previous studies conducted by the city, which looked at communities similar to Columbia, concluded that lowering residential speed limits has little to no effect on the speed at which people drive.
In contrast, a study conducted earlier this year by MU associate engineering professor Carlos Sun found significant reductions in speed on the streets of the Shepard and Rothwell neighborhoods.
"You can teach an old dog a new tricks," Public Works Director John Glascock said during a discussion of the MU study that the report notes recorded average speed reductions of up to 6.21 mph after the limits were reduced from 30 to 25 mph.
The Public Works Department is unsure at this point how much it will cost to replace the city's residential speed limit signs, although a 2007 Public Works report estimated that there are 1,700 residential street segments that would need to have their signs replaced.
To keep costs down, Glascock said the city would most likely repaint signs with the new limits.
Supervising Traffic Engineer Scott Bitterman said the city would need to seek outside help if it wished to repaint all residential speed limit signs at once. He said if the city opts to phase in the signs, city workers will be able to handle the work.
"My thought is that we should phase it in because of current budget concerns," Sixth Ward Councilwoman Barbara Hoppe said.
Part of Sun's research for the residential speed limit study analyzed past literature on speed limits and their effectiveness, including a 1995 report by the European Transport Safety Council.
According to the ETSC study, there is a 45 percent fatality rate in situations where a pedestrian is hit by a car traveling 30 mph, but at 20 mph, the fatality rate is reduced to 5 percent.
"If you want to prevent a child from being hit by a car, a 20 mph speed limit is more effective," First Ward Councilman Paul Sturtz said.
It is not clear at this point whether the city will consider placing 20 mph speed limits in some residential zones, but officials plan to conduct further studies on higher volume streets.