Find a grid reference for a breakdown location
The short answer
In the US, a grid reference for a breakdown usually means a set of map coordinates. The most common are latitude and longitude, which most smartphones can display from their built-in GPS. Some emergency and public-safety agencies also use the US National Grid (USNG), a standardized grid coordinate system. To get either one, open a map or compass app on your phone, drop a pin or check your current position, and read out or copy the coordinates shown.
There is one important qualification. The term "grid reference" most often refers to the Ordnance Survey system used in Great Britain, and that format does not apply to US roads. If a US dispatcher, roadside assistance provider or tow operator asks for your location, latitude and longitude plus a plain-language description is the safest default. Use USNG only if the agency specifically asks for it.
If you are in danger, for example stopped in a live traffic lane or involved in a collision, call 911 first. Get to a safe position before you spend time on coordinates.
Coordinate formats you may be asked for
Format | What it looks like | Where it is typically used; Latitude and longitude, decimal degrees | Two signed decimal numbers: latitude first, then longitude | Phone map apps, roadside assistance apps, most dispatch systems; Latitude and longitude, degrees-minutes-seconds | Degrees, minutes and seconds with N/S and E/W letters | Some GPS units, compass apps and printed maps; US National Grid (USNG) | Grid zone, 100,000-meter square letters, then easting and northing digits | Some emergency management and public-safety agencies; Ordnance Survey grid reference | Two letters followed by digits | Great Britain only; not used on US roads
In decimal degrees for the continental US, latitude is positive (north) and longitude is negative (west). If you read coordinates aloud, say the minus sign or say "west". Dropping the sign or swapping the two numbers can put the pin somewhere else entirely.
A USNG reference is built from these parts, written in this order:
[Grid zone designation] [100,000-meter square ID] [Easting] [Northing]; Grid zone designation = number + letter; Square ID = two letters; Easting / Northing = equal-length digit groups; (more digits = more precise)
How to find your coordinates on the spot
Map app: Open your phone's map app and wait for the location dot to settle. Press and hold on the dot, or tap it, to drop a pin. The coordinates usually appear in the pin details, where you can copy or share them. Compass app: On some phones, the built-in compass app shows the current latitude and longitude on the main screen. Roadside assistance or insurer app: Many of these apps send your GPS position automatically when you request help. Check that the pin on the map matches where you actually are before you confirm. Vehicle telematics: Some vehicles with connected services can send the vehicle's location to an assistance center. Availability depends on make, model year, trim and an active subscription, so check your owner's documentation. Dedicated GPS unit: Standalone navigation or handheld GPS devices typically have a position or "where am I" screen showing coordinates. Some can also be set to display USNG or MGRS (the military grid that USNG is aligned with).
Menu names and steps vary by phone operating system, app and version. If the steps above don't match your screen, check the app's help section.
Roadside cues that confirm your location
GPS coordinates can be off, especially in deep valleys, dense urban areas, tunnels or under heavy tree cover. Responders also navigate by road features, so pair your coordinates with as many of these cues as you can see safely:
Route name or number, and the direction of travel (for example, northbound or eastbound). The nearest mile marker or reference post, usually small signs on the shoulder or median. The last exit you passed or the next exit ahead, by number or name. The nearest cross street, overpass, bridge, rest area or named landmark. Which side of the road you are on, and whether you are on the shoulder, in the median, on a ramp or in a travel lane. A short vehicle description: color, make and body style, so the right vehicle is easy to spot.
Direction of travel matters most on divided highways. The two sides of the road can be far apart by the nearest crossover, so responders need to know which carriageway you are on.
What the dispatcher may already know
When you call 911 from a mobile phone, the system may pass an estimated location to the dispatcher. That estimate can be approximate, and its accuracy depends on your phone, carrier and local equipment. Still give your coordinates and roadside cues, and confirm them if the dispatcher reads a location back to you.
Limits of this guide
No specific evidence was available for this guide on individual apps, vehicle connected-service features, or which US agencies accept USNG references. The steps above reflect general principles of how coordinate systems and phone location features work. For your situation, check the documentation for your phone, your roadside assistance provider and, where relevant, your vehicle's model year and trim.
