How Tall is Your RV?
This document explains why you should never enter incorrect or falsely inflated height (or width) values for your RV when using any form of RV-safe navigation products, whether physical devices or software-assisted products. This includes the RV LIFE Pro tools, such as RV LIFE Trip Wizard and the RV LIFE mobile app, which feature RV-safe navigation. Only accurate measurements should be entered in any navigation and trip-planning tools or devices.
RV LIFE uses a well-known industry source to pre-populate the height, length, and weight values of your RV in our RV LIFE tools, when available. However, as an RVer, you should always confirm those values with your RV manufacturer or measure your RV yourself, especially if modifications have been made or equipment has been added to the RV.
What Does the Law Say?
Per the Federal Highway Administration and Department of Transportation (DOT) regulations, any vehicle taller than 13’ 6” is considered an Oversize Load. Oversized or overheight vehicles are restricted to designated overheight or oversize travel corridors. For any vehicle over 13’ 6”, any navigation tool that considers height will route only onto those routes and corridors approved for oversized travel.
For an RVer who falsely inflates their height above the 13’ 6” limit, routing will seem haphazard, confusing, and long. This also applies to a width of over 8 feet 6 inches (102 inches), though the width setting is not yet available in RV LIFE Pro.
Do You Need a Height Buffer? (Hint: No)
As an RVer, you do not need to add or “pad” the settings to provide a buffer, as this is already taken into consideration by the Department of Transportation. RVers who feel tempted to add a measurement buffer run the risk of exceeding normal limits and inadvertently put themselves in that oversized/overheight category, and will be forced to follow routes designated for those kinds of loads.
What Do the Clearance Sign Numbers Mean?
The posted clearance signs provided by the state are an indication of the height a vehicle can be and still safely pass under the tunnel, bridge, or overpass. States in the U.S. typically provide an additional height allowance over the posted clearance height of bridges and overpasses on major highways.
The posted clearance height used by RV LIFE is provided by our map provider, HERE Technologies, a multinational company specializing in location data and technology, and used by trucking companies around the world for safe truck routing based on height.
The information below is intended as a guideline to understanding posted clearance signs provided by states for bridges, tunnels, and overpasses. When in doubt about clearance in a specific area, research by state, route, or type of highway (e.g., state routes vs. interstates) for more precise figures and state DOT policies.
Clearance Guidelines for RVers
🛣️ Standard Allowance Over Posted Clearance
- General Rule: Most states provide an additional safety margin of 3 to 6 inches above the clearance height stated on signs.
- Example: If a bridge sign states 13'-6" clearance, the actual measured clearance might be closer to 13'-9" to 14', depending on the state and location.
- This buffer is intended to account for road surface variations, pavement overlays, and to provide a safety cushion for drivers.
- As long as your RV height measures at or below the posted clearance value, you can safely pass beneath. Remember, the posted clearance sign provided by the state is an indication of the height a vehicle can be and still safely pass under the tunnel, bridge, or overpass.
🚧 Why the Allowance Exists
- Construction Tolerances: During bridge or overpass construction, slight variations are common. Allowances help mitigate risk.
- Road Resurfacing: Over time, new layers of asphalt reduce clearance. States factor in these changes when setting posted heights.
- Vehicle Safety: The additional height helps avoid collisions with vehicles whose heights are near the posted limit but still technically safe to pass.
🚚 Federal and Industry Standards
- The Federal Highway Administration (FHWA) recommends minimum vertical clearances of 16 feet for new construction on interstate highways.
- However, older infrastructure may still have clearances as low as 13’-6”, especially on secondary roads.
- Most trucking companies assume 13’-6” as a standard maximum legal vehicle height to accommodate older structures.
🧭 Variation by State
- Some states have published policies for minimum “actual” versus. “posted” clearance values.
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For instance:
- California DOT often uses 6 inches.
- Illinois also allows up to 6 inches, depending on local factors.
- Texas DOT provides 3 inches extra as a standard design buffer.
✅ Key Takeaways
- Average extra allowance: Typically 3 to 6 inches above posted clearance.
- Not guaranteed: Always treat the posted height as the maximum safe limit.
- Vehicle planning: Drivers of tall vehicles (13’ or more) must use designated truck routes and avoid low-clearance roads.
📏 Not a Guarantee — Drivers Still Need Caution
- Despite the allowance, drivers should always assume the posted height is the maximum safe clearance.
- Legal responsibility for clearance issues typically rests with the driver or carrier, not the state.
- You should always confirm those values with your RV manufacturer or measure your RV yourself, especially if modifications have been made or equipment has been added to the RV.