Can I add a heads-up display to my car?

Yes—most drivers can add an aftermarket heads-up display (HUD) to their car using plug-in OBD-II units, GPS/smartphone-based projectors, or CarPlay/Android Auto HUDs that reflect on a small combiner glass or the windshield. Expect prices from about $30 for basic speed readouts to several hundred dollars for feature-rich units, with some professional retrofit kits costing more. Below is what to know about types, compatibility, installation, laws, costs, and practical pitfalls.

What a HUD is and the main ways to add one

A heads-up display projects key driving info into your line of sight so you don’t have to look down at the instrument cluster. Aftermarket options vary in how they get data, where they project, and how much integration they offer. Here are the common types you’ll see on the market and what they do.

• OBD-II plug-in HUDs: Draw speed/RPM and other metrics directly from your car’s diagnostic port (standard on most U.S. vehicles 1996+). These typically sit on the dash and reflect onto the windshield or a small transparent combiner.
• GPS-based portable HUDs: Use onboard GPS to display speed and basic navigation prompts without tapping the car’s data bus; useful when OBD compatibility is limited.
• Smartphone-app HUDs: Mirror a phone app’s speed, navigation, or alerts onto the windshield using a reflective film or a small combiner lens; setup is simple but brightness and legibility vary.
• CarPlay/Android Auto HUDs: Dedicated HUDs that connect wirelessly or via USB to your phone to show navigation, media, and calls on a combiner glass, sometimes with additional OBD data.
• Integrated retrofit kits: More expensive systems that mount discreetly and may project onto the windshield with a dedicated projector; usually require professional installation and are closest to factory look-and-feel.

Functionally, the choice comes down to data source (OBD vs. GPS vs. phone), projection method (windshield vs. combiner), and how much integration you want with navigation and vehicle metrics.

Compatibility and legal considerations

Vehicle compatibility

For OBD-II HUDs, most cars sold in the U.S. since 1996 (and in the EU since the early 2000s) will provide basic speed and RPM. Some advanced metrics—like transmission temperature or battery data on EVs—may not be available without manufacturer-specific PIDs. Hybrids and EVs can be hit-or-miss for nonstandard data; when in doubt, choose a GPS-based unit or a CarPlay/Android Auto HUD for navigation info and GPS speed. If your vehicle predates OBD-II, stick to GPS or phone-based HUDs.

Windshield and visibility

Modern laminated windshields can cause a faint double image (“ghosting”) because the reflection bounces off two glass layers. A small reflective film placed where the HUD projects can reduce ghosting and sharpen the image. Polarized sunglasses may dim HUD visibility, especially with certain projection angles. Also consider dash depth and seating position so the image appears at a comfortable eye line without blocking the road.

Laws and regulations

HUD projections themselves are generally legal when they don’t obstruct the driver’s view, but physical mounts, suction cups, or combiner screens may fall under “windshield obstruction” rules that vary by state or country. In parts of the U.S., items attached to the central windshield area can be prohibited, while small devices in specified lower corners may be allowed. Check your local regulations before mounting anything on the glass and keep devices out of airbag deployment zones.

What to look for when choosing a HUD

Before buying, compare features and specifications to ensure the HUD will be legible, reliable, and compatible with your car and driving conditions.

• Brightness and auto-dimming: Look for high-nit output with day/night modes; glare and sun washout are common issues with cheaper units.
• Data source and accuracy: OBD-II units provide true vehicle speed; GPS-based speed can lag briefly but works in nearly any car.
• Display content: Decide whether you just need speed and RPM or also navigation prompts, turn-by-turn, media, and calls via CarPlay/Android Auto.
• Projection method: Windshield reflection is cleaner-looking but may ghost; a combiner glass avoids ghosting but adds a small on-dash screen.
• Power and cable management: Check for clean 12V/USB power options, auto on/off with ignition, and the inclusion of cable routing clips.
• Firmware updates and app support: Active support helps with bug fixes, PID compatibility, and new features.
• Heat tolerance and build: Units should handle hot dashboards; look for operating temp specs and sturdy mounts.
• OBD-II passthrough: A Y-splitter retains access for diagnostics while powering the HUD.
• Return policy and reviews: Availability and quality vary widely; favor recent reviews and clear return windows.

Balancing legibility, features, and installation complexity often leads buyers to either simple OBD units for speed/RPM or CarPlay/Android Auto HUDs for navigation-centric use.

Installation overview

Most DIY installs are straightforward. These steps outline a typical setup; always follow your device’s instructions.

1. Choose placement: Sit in your normal driving position and mark where the image should appear without blocking the road.
2. Prepare the surface: Clean the dash and, if using windshield projection, position and apply the reflective film to reduce ghosting.
3. Route power: Run the cable to a 12V outlet or the OBD-II port; use trim-friendly tools to tuck cables and avoid airbag paths.
4. Connect the device: Plug into OBD-II for data or pair with your phone for GPS/CarPlay/Android Auto.
5. Calibrate: Set units (mph/km/h), adjust brightness and mirror mode, and fine-tune image position and focus if available.
6. Test drive: Verify speed accuracy (compare to the car’s cluster and GPS), check for reflections/glare, and adjust as needed.
7. Secure and finalize: Affix the mount firmly, add cable clips, and confirm auto on/off behavior with ignition.

A careful placement and a short test drive go a long way toward preventing long-term visibility or glare issues.

Costs and what to expect on the market

Prices vary by features and integration level. Here’s a realistic snapshot of current aftermarket pricing and what you typically get at each tier.

• $30–$80: Basic OBD-II or GPS HUDs showing speed, RPM, coolant temp, and simple alerts; usually windshield reflection with optional film.
• $120–$250: Midrange units with better brightness, combiner glass, and cleaner mounting; some add simple nav prompts via phone link.
• $250–$500: CarPlay/Android Auto HUDs with turn-by-turn navigation, media, and calling on a clear combiner; some can merge limited OBD data.
• $700–$1,500+: Integrated retrofit kits with discreet mounting and higher-end optics; typically require professional installation.

Brand availability changes often in this category, so prioritize recent, verified reviews, clear specs on brightness and heat tolerance, and sellers with strong return policies.

Common pitfalls and troubleshooting

HUDs are sensitive to mounting and lighting. Watch for these issues and fixes.

• Double image/ghosting: Use the included reflective film or switch to a combiner glass to eliminate the second reflection.
• Too dim or too bright: Enable auto-dimming and adjust manual brightness for night driving to avoid distraction.
• Speed discrepancies: Small differences between OBD speed and GPS are normal; calibrate offset if your unit supports it.
• No OBD data on hybrids/EVs: Switch to GPS-based display or confirm compatibility/PIDs through the manufacturer.
• Battery drain: Ensure the unit powers down with ignition; use a switched 12V source or enable auto-sleep modes.
• Overheating/mount failure: Use heat-rated adhesives and avoid placing the unit under direct sunlight where possible.
• Legal concerns: If stopped, be ready to show the device doesn’t obstruct view; mount low and outside airbag paths.

Most issues are solvable with correct placement, calibration, and the right accessories (film, cable clips, OBD splitter).

When professional installation makes sense

If you want a factory-like look, need windshield projection aligned precisely, or drive a vehicle with limited cable routing options, a professional installer can mount, power, and calibrate the HUD cleanly and safely. Expect $150–$400 for labor, more if the kit requires trimming or custom brackets.

Summary

You can add a HUD to most cars, from simple OBD-II or GPS speed readouts to CarPlay/Android Auto units that float navigation in your line of sight. Check compatibility, understand local windshield-mount rules, plan for glare and ghosting, and budget anywhere from tens to hundreds of dollars depending on features. With careful selection and setup, an aftermarket HUD can improve situational awareness without cluttering your dashboard.

Are heads-up displays legal in the US?

While there is some potential for misuse of redundant controls, there is no corresponding potential for “misuse” of redundant displays. That is, the subject head up displays will either be visible or invisible to the driver. If they are visible, there is no issue.

Do aftermarket head-up displays work?

Do aftermarket head-up displays work? Yes. Many are good designs that can rival the HUD that might be included with today’s new cars.

Are car HUDs worth the cost?

As HUD paints and highlights virtual paths onto the road, it is far easier for a driver to follow the directions. It can also add markers and visible signs on the road, making your driving experience more safe, dynamic, and exciting. It can be yet another distraction for the driver.

How much does it cost to add a heads-up display?

Adding a Heads-Up Display (HUD) can range from $40 for a simple smartphone-based unit to over $1,000 for a professional installation of an integrated system. For existing vehicles, you can purchase an aftermarket HUD for as little as $40-$100 that projects basic information, but a true factory-style integrated HUD requires significant, expensive modifications to your car’s dashboard and windshield, making it cost-prohibitive for many. 
Aftermarket HUDs

• What it is: These are external units that mount on your dashboard or windshield. Some are specialized devices, while others are phone mounts that display information on a reflective surface. 
• Cost: You can find simple aftermarket units for under $100. 
• Installation: They are generally easy to install, often requiring just a dashboard placement and connection to a power source or a smartphone. 

Adding a Factory-Style HUD (Integrated HUD)

• What it is: This involves integrating a HUD into your vehicle’s dashboard and often a specially designed windshield. 
• Cost: This is a very expensive undertaking. 
  • Components: You’ll need a new dashboard, a HUD-compatible windshield, and various electronics. 
  • Labor: Extensive labor for removal, installation, and wiring is required. 
  • Software: The vehicle’s software must be coded to recognize and utilize the new HUD, which can be costly. 
• Feasibility: It is often not a financially sound option; many professionals advise that it’s cheaper to purchase a new car with an already equipped HUD. 

Factors influencing cost:

• Type of HUD: Aftermarket units are much cheaper than factory-integrated ones. 
• Features: More advanced HUDs that display more features and information will be more expensive. 
• Installation Method: Professional installation for an integrated HUD is a significant cost factor.