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Road Signs

US-23 sign in northern lower Michigan.
Department of Transportation

Road Signs

Road signs are an important part of traffic safety. They provide important information to road users, create order on the roads, and they keep people safe. More than 1,120 people die in Michigan traffic-related crashes every year. Effective and safe road signs can save lives, prevent injuries and property damage, and can improve traffic flow.

Keeping a focus on safety, MDOT routinely replaces traffic signs on highway corridors as part of a 100 percent federally funded statewide sign replacement program. Supports for traffic signs, frequently placed close to the roadway, can become deadly hazards when struck by a vehicle if not designed, manufactured, and constructed to break away upon impact. That is why when MDOT replaces old traffic signs, crews also replace sign posts to ensure safety. Coordinating the replacement of sign posts with traffic sign replacement also minimizes costs.

Learn more below about MDOT sign safety and enhancements.

A Tourist Oriented Directional Sign along M-45 west of Allendale.

Advertising Signs

Businesses serving travelers and tourists can have signs placed along state trunklines.

Advertising Along State Trunklines
A memorial sign showing the designation of the Aretha L. Franklin Memorial Highway.

Memorial Highway Signs

Memorial Highway signs are dedicated to individuals or groups through state statute.

Memorial Highway Sign Guidelines
Political voting sign graphic.

Political Signs

Rules for placement of political signs on state roads (I, M and US routes).

Political Sign Guidelines

Sign Safety & Enhancements

It's all about SAFETY!

Road Sign Font

Research shows that Clearview font on guide signs reduces fatal and injury crashes by 5 percent on rural roads, 23 percent on urban non-freeways, and 3 percent on freeways compared to standard highway font. The greatest reductions were realized at night for all crash types. These reductions were 26 percent for urban non-freeways, 34 percent for rural non-freeways, and 31 percent for freeways. Additionally, a research survey found that drivers have a strong preference for Clearview font especially during inclement weather, at night and from a distance. Clearview font is especially beneficial to older drivers. By 2030, one in five drivers will be age 65 or older.

MDOT has adopted Clearview font as the standard for all newly upgraded guide signs.

A Lapeer County sign that shows Clearview font.

Wrong Way Warning Systems

A Wrong Way Warning System is designed to alert motorists that are driving the wrong way on freeways. Cameras detect when a vehicle is approaching; when that happens, high-intensity red LED flashing lights mounted on each of the wrong way signs are activated.

The Wrong Way Warning System is designed to prevent one of the most serious types of traffic crashes.

Wrong-Way Detection System on US-131 in Grand Rapids

Fluorescent Yellow Sheeting

MDOT has adopted fluorescent yellow sheeting as the standard reflective background sheeting for warning signs. This relatively inexpensive material increases the visibility of a traffic sign and provides greater contrast against the surroundings. Fluorescent yellow sheeting is used on warning signs as they are replaced on MDOT roads.

This safety enhancement means brighter, more visible signs.

Fluorescent yellow sheeting on a Bridge Ices Before Road sign.

Reflective Post Sheeting

MDOT has begun to require the installation of reflective post sheeting for several types of signs. It has been found that the use of reflective post sheeting has an added safety and operational benefit, particularly at night. The post sheeting gives users a clue as to the path of the road while bringing attention to the sign.

This addition to specific signs helps drivers at night.

Reflective post sheeting on a stop sign.


Retroreflectivity is a scientific term that describes the ability of an object to redirect light back to its source. Retroreflective traffic signs use small glass beads or microprismatic reflectors to return light from a vehicle’s headlights back to the driver’s eyes. The retroreflective properties of traffic signs deteriorate over time, due to severe weather, exposure to the sun and damage from other factors. Traffic signs must be replaced on a timely basis or they can become difficult to see and read at night.

Highly retroreflective signs are especially beneficial to older drivers. However, bright, more visible traffic signs help drivers of all ages to quickly read and react to the information which reduces nighttime crashes. 

Highly reflective directional sign.