For passenger vehicles the new speed limit will be 70 mph from east of Veterans Memorial Parkway north to Shattuck Road.
The new speed limit will be in effect once the new signs are installed.
North of Shattuck Road was already 70 mph.
The speed limit increase came about after the Michigan Department Of Transportation (MDOT) and the Michigan State Police (MSP) conducted a speed and traffic study over a multi-year period.
Both setting realistic speed rules and the 85th Percentile Rule were factors in the decision.
The 85th Percentile Rule is a nationally accepted guideline that uses speed studies to help determine speed limits.
The rule states that the appropriate speed limit is one that is not exceeded by 85 percent of drivers along a corridor.
"Setting realistic speed limits is a major factor in preventing crashes on Michigan highways," said Jack Hofweber, MDOT Bay City Transportation Service Center manager.
Additionally, Hofweber points out that there have been improvements made along I-675 the last few years that were meant to increase safety.