Speed limit changes are looming for Rochester.

Signs on the edge of the city marking the shift from 30 mph to 25 mph for most of Rochester's residential streets are expected to be posted in May, which will spur the citywide change.

The change follows a December decision by the Rochester City Council, which was a compromise up from a 20 mph recommendation.

For city streets with a speed limit other than 25 mph, changes take effect as soon as signs are installed, which is expected to begin within weeks.

RELATED: 6 things to know about Rochester's speed limit change

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“We used the ‘Safe Systems’ approach to determining the speed limits on city streets,” said Rochester City Engineer Dillon Dombrovski. “This approach puts the safety of all road users as the top priority when making decisions related to our streets."

“Not only will this speed limit reduction make our streets safer, it will make our neighborhoods more livable and advance our efforts towards zero deaths,” he added.

Dombrovski said studies show vehicle speed at the time of impact directly correlates to whether a person will live or die, so reducing speed limits on streets where people walk, bike and play is expected to help prevent severe injuries and death.

A person hit by a car traveling at 40 mph is five times more likely to die than a person hit by a car traveling at 20 mph, according to a speed limit evaluation prepared by Rochester Public Works last year.

Additionally, city staff point to a growing body of research showing that speed limit changes can lead to measurable declines in speeds and crashes on city streets, even without increased enforcement or engineering changes.

Sam Budzyna, the city’s traffic and parking manager, has said Public Works isn’t suggesting added enforcement of speed limits on residential streets, noting that current enforcement is limited based on patrol availability and department priorities.

However, a 2018 Insurance Institute for Highway Safety study in Boston reportedly found the sole act of reducing the citywide speed limit from 30 mph to 25 mph reduced speeding overall and dramatically decreased the instances of vehicles traveling faster than 35 mph.

The city has approximately 345 miles of residential streets, which make up the largest portion of its 500 miles of city streets, but not every city-owned street in Rochester will see changes.

Roads such as Elton Hills Drive, 37th Street Northwest and Broadway Avenue outside of the business district will remain at their current posted speeds.

Additionally, speed limits on county- and state-owned roads, such as East Circle Drive, West Circle Drive and Marion Road, are not changing.

Full implementation of new signs and new speed limits is expected to take six months, and the city is ramping up an educational campaign as part of the change.

Speed Limit Evaluation by inforumdocs on Scribd