Driving safety guide · Ford of Peoria · Peoria, IL
Mile Markers Explained
Those small signs with a number along the highway are more useful than they look. Here is what the federal Manual on Uniform Traffic Control Devices (MUTCD) says about mile markers, which it calls reference location signs, and how they tie in to exit numbers.
The short answer
Mile markers show your distance point along a route. Numbering starts at zero at the south or west state line and counts up, and freeway exit numbers correspond to the posted mile markers. They also help you tell emergency responders where you are.
What mile markers are
The MUTCD calls mile markers reference location signs. They show a distance point along a highway, and they exist to help road users estimate their progress, to provide a way to identify the location of emergency incidents and traffic crashes, and to aid highway maintenance and servicing.
Where they are required: on all freeways, and on expressways that are on a route with reference location sign continuity, unless enhanced reference location signs are used instead. They may also be installed on any section of a highway route or ramp.
If you ever need to report a crash or a breakdown, the nearest mile marker and your direction of travel help describe where you are. See also what to do if you hit a deer and our guide to speed limits.
From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Section 2H.11, read November 4, 2026.
Types of mile markers
The MUTCD describes four kinds:
| Sign | What it shows |
|---|---|
| Reference Location (D10-1 to D10-3) | A whole-number distance point along the highway. |
| Intermediate Reference Location (D10-1a to D10-3a) | The same information plus a tenth-of-a-mile decimal, for placement between whole-number points. |
| Enhanced Reference Location (D10-4) | A vertical green sign with a white legend: the cardinal direction for the roadway, the route shield and the mile number. |
| Intermediate Enhanced Reference Location (D10-5) | The enhanced design with a bottom line giving the tenth of a mile after a decimal point. |
From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Sections 2H.11 and 2H.12, read November 4, 2026. Intermediate signs may be placed every tenth, two tenths or half mile. When they are used, the whole-mile sign shows a decimal point and a zero.
How the numbering works
Where zero is: zero distance begins at the south and west state lines, or at the south and west ends of routes that begin within a state.
Continuous within a state: distance numbering is continuous for each route within a state. Where routes overlap, only one keeps continuous numbering, and if one of them is an Interstate, the Interstate is chosen.
After an overlap: on the route that lost continuity, the first marker past the overlap should show the total distance traveled on the route, so drivers can compare it with their odometer.
Divided highways: distances are measured on the northbound and eastbound roadways, and the southbound or westbound markers are set directly opposite them.
From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Section 2H.11, read November 4, 2026.
Mile markers and exit numbers
The MUTCD requires interchange exit numbering to use the reference location sign method, and says the consecutive exit numbering method shall not be used. Exit numbers correspond to the posted mile markers.
The MUTCD explains that this helps drivers work out destination distances and travel mileage, helps them report their location after an incident or breakdown, helps responders, and means exit numbers do not have to change when new interchanges are added.
Suffix letters: letters such as A and B are only used where more than one exit is tied to the same mile point, and they are assigned in alphabetical order starting with A.
From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Section 2E.22, read November 4, 2026.
Where mile markers go
Side of the road: mile markers are installed on the right-hand side of the roadway. Where conditions limit that, they may go in the median, and on two-lane conventional roads they may be on one side only and back to back.
Distance from the road: they may be placed up to 30 feet from the edge of the pavement, with a minimum mounting height of 4 feet.
Close enough: a marker that cannot go in the correct location may be moved up to 50 feet either way. If it cannot be placed within 50 feet, it should be left out.
From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Section 2H.11, read November 4, 2026.
Get your vehicle ready for highway miles
The Works® at Ford of Peoria includes a synthetic blend oil change, tire rotation and pressure check, brake inspection, Multi-Point Inspection, fluid top-off, battery test, and a filter, belts and hoses check.
Schedule service online and see our service specials first. Ford of Peoria is at 2211 W. Pioneer Pkwy. in Peoria. Get directions.
Ford of Peoria service hours
| Days | Hours |
|---|---|
| Mon-Fri | 7 a.m.-5:30 p.m. |
| Sat | 8 a.m.-noon |
| Sun | closed |
From Ford of Peoria's website, November 4, 2026. Holiday hours can differ.
Mile marker FAQ
What is a mile marker?
Mile markers are what the MUTCD calls reference location signs. They show a distance point along a highway to help drivers estimate their progress, identify the location of emergency incidents and traffic crashes, and aid highway maintenance and servicing.
Where does mile marker 0 start?
The MUTCD says zero distance begins at the south and west state lines, or at the south and west ends of routes that begin within a state. The numbers count up from there.
Why do exit numbers match the mile markers?
The MUTCD requires interchange exits to be numbered by the reference location method, so each exit number corresponds to the posted mile markers. Consecutive exit numbering (1, 2, 3...) is not allowed under the MUTCD.
What do mile markers with a decimal mean?
Those are intermediate reference location signs. They show the tenth of a mile and may be placed every tenth, two tenths or half mile between the whole-number markers.
What is a green mile marker with a route shield?
That is an enhanced reference location sign. It has a green background with a white legend, the direction of travel on top, the route shield, and the mile number.
Do mile markers start over at a state line?
Under the MUTCD, yes. The MUTCD says distance numbering is continuous for each route within a state and that zero begins at the south and west state lines, so each state numbers its own section of a route. Where routes overlap, only one route keeps continuous numbering, and an Interstate is chosen if it is one of them.
Which side of the road are mile markers on?
Normally the right-hand side. Where conditions limit that, they may be placed in the median, and on two-lane conventional roads they may be on one side only, back to back. They may be up to 30 feet from the edge of the pavement.
What does The Works at Ford of Peoria include?
The Works® at Ford of Peoria includes a synthetic blend oil change, tire rotation and pressure check, brake inspection, Multi-Point Inspection, fluid top-off, battery test, and a filter, belts and hoses check.
Book a routine checkup
Book The Works, which includes a brake inspection, tire rotation and pressure check, and battery test, at Ford of Peoria.
Sources
Sign descriptions are from the Federal Highway Administration's Manual on Uniform Traffic Control Devices, 11th Edition with Revision 1 (Revision 1 dated December 2025), read November 4, 2026. This page is a plain-language summary of national standards, not legal advice; state law sets the rules of the road where you drive. Service details, address and hours are from Ford of Peoria's own website, checked the same day. Photo is illustrative.
- Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1 (Sections 2E.22, 2H.11, 2H.12), Federal Highway Administration, Revision 1 dated December 2025 (PDF updated February 12, 2026), read November 4, 2026
- General service: The Works, Ford of Peoria, November 4, 2026
- Address and service hours (structured data), Ford of Peoria, November 4, 2026