---
title: "Radar Speed Signs & Driver-Feedback Displays"
description: "Radar 'Your Speed' driver-feedback signs, full-matrix message signs and variable speed-limit displays — how to choose display size, power and data logging."
canonical: "https://www.solarthingz.com/guides/radar-speed-signs-driver-feedback"
---

![Illustration: a solar radar speed display showing a driver's speed on a residential street.](https://www.solarthingz.com/scenes/neighborhood-radar.3386360f-mh-640.jpg)

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Buying & compliance guide

# Radar Speed Signs & Driver-Feedback Displays: A Buyer's Guide

Updated October 1, 2026

A **radar speed sign** — also called a driver-feedback or "Your Speed" sign — reads each approaching vehicle with Doppler radar and shows the driver their own speed on a bright LED display. It's one of the most effective traffic-calming tools there is: no ticket, no enforcement, just immediate feedback that gets most drivers to ease off. This guide covers the device tiers (from a $900 flashing speed-limit sign to a full radar system), how to size the display to the road, the power options, and the data features that turn a sign into a before-and-after speed study.

## Pick the right device tier

Speed management is a ladder. Start with the cheapest device that actually addresses the complaint — a flashing speed-limit sign is a fine gateway, but it can't tell you (or the driver) how fast anyone is going. A radar feedback sign does, and a full-matrix or variable speed-limit sign escalates from there.

| Tier | What it is | Catalog price band | Reach for it when |
| --- | --- | --- | --- |
| Flashing speed-limit sign | A solar MUTCD speed-limit sign with built-in flashing LEDs — posts and flashes the limit, no radar. | ≈$900 | You just need the posted limit to stand out (a school zone or gateway), not to measure each driver's speed. |
| Radar "Your Speed" feedback sign | Doppler radar reads each vehicle's speed and shows it back on a big LED display, with a strobe for violators. | ≈$2,700–$8,000 | Speeding complaints on a street, campus or HOA road — showing drivers their own speed is the classic calming move. |
| Full-matrix (FM) message sign | A feedback display that also shows programmable messages — "SLOW DOWN", a smiley/frown, or custom text. | ≈$3,200–$5,300 | You want the display to coach as well as measure, or to double as a small changeable-message sign. |
| Variable speed-limit sign | A driver-feedback sign with a changeable posted limit (SP550). | ≈$4,300–$5,000 | Variable limits on a corridor. |

Price bands are catalog-wide, rounded, and span the size and power options within each tier — see each product page for live pricing. The [flashing speed-limit signs](https://www.solarthingz.com/products/5mph-speed-limit-sign) come in 5–35 MPH; the radar feedback signs are the [SPEED RADAR SIGNS](https://www.solarthingz.com/collections/speed-radar-signs) collection.

## How a driver-feedback sign works

Every radar feedback sign does the same three things: a **K-band Doppler radar** (around 24.1 GHz) measures the speed of the nearest approaching vehicle, an **LED display** shows that number back — usually under a fixed "YOUR SPEED" legend — and a **speed-violator strobe** flashes when a driver is over a threshold you program. An ambient light sensor dims the display at night so it's readable without glare. The whole unit is weather-sealed and, in the solar models, entirely self-powered.

## Sizing the display to the road

The key spec is how far out a driver can _read_ the number: bigger digits and brighter LEDs are legible from farther away, which matters more the faster the approach. Match the rated legibility distance to the approach speed so a driver sees their speed with time to react. Here's how the range lines up across the catalog:

| Model | Display | Legibility | Power |
| --- | --- | --- | --- |
| 11" Your Speed | 11″ two-digit | Up to ~1,000 m | 120 W bifacial solar + 36 Ah lithium |
| SP100 | 11″ two-digit | Up to ~300 ft | Solar (20 W/50 W) or AC |
| EV11 / EV12 / EV15 | Two-digit, 200+ LEDs | Long-range, high-brightness | Solar (20 W/50 W), cloud-connected |
| SP550 variable limit | Speed + changeable limit | Up to ~1,200 ft | Solar (50 W) or 100–240 V AC |
| SP700 | Full matrix, 1,300+ LEDs | Highway-scale | 140 W solar |

Legibility figures are the manufacturers' rated distances and vary with weather, sun angle and mounting height — treat them as relative, and step up a size when the approach is fast or the sight line is long. The [EV18-FM](https://www.solarthingz.com/products/solar-led-radar-speed-sign-ev18-fm) and [SP700](https://www.solarthingz.com/products/solar-led-radar-speed-sign-sp700) are the largest, highway-scale displays.

## Power & mounting

Power is usually the first real decision. Most models are **solar** (20 W panels on the compact SP/EV signs up to 140 W on the big SP700, and a 120 W bifacial panel on the 11″ Your Speed sign), and several also offer **AC** — the [SP550](https://www.solarthingz.com/products/solar-powered-variable-speed-limit-driver-feedback-sign) takes 100–240 V AC or a 50 W solar panel. Batteries range from a 12 V / 18 Ah pack on the SP/EV line to a 36 Ah lithium on the Your Speed sign, giving 1–5 days of autonomy (24-hour continuous on the Your Speed). Everything mounts on a **3″ round pole**; add the [universal radar mounting bracket](https://www.solarthingz.com/products/universal-mounting-bracket-for-radar-speed-signs) for other poles, or the [radar speed sign dolly](https://www.solarthingz.com/products/radar-speed-sign-dolly) to redeploy a sign around town without pouring a foundation.

## Data & smart features

Beyond the live display, the value of a radar sign is the **data**. The EV series ships with a year of cloud connectivity, and the signs log the speeds they measure — so you can pull a before-and-after study to prove a calming program worked, set the violator-strobe threshold to your posted limit, and let the auto-brightness handle day-to-night readability. Speed reads out in MPH or KM/H, typically to within ±1 MPH.

!

Spec tip

Deciding between a fixed pole-mounted sign and a portable one? A dolly-mounted radar sign lets an HOA or town rotate one unit between problem streets and collect a week of data at each — often a better first buy than a permanent install. Send us the road, the posted speed and the power situation and we'll spec the model.

## Common questions

### Do radar speed signs actually slow traffic down?

Showing drivers their own speed is a well-established traffic-calming measure — most drivers ease off when the number lights up, especially with a violator strobe. Effectiveness depends on siting and whether you follow up with the logged data, which is why the signs record the speeds they measure.

### Solar or AC power?

Solar is the default and needs no wiring — ideal where you can't run AC. If you have power at the pole and want zero dependence on sun (a shaded corridor, a variable-limit sign that runs a heavier display), choose a model with an AC option such as the SP550.

### What digit size do I need?

Match legibility distance to approach speed. An 11″ two-digit display suits most residential and collector streets; step up to a larger full-matrix display (EV18-FM, SP700) for higher-speed or wider roads where drivers need to read it from farther out.

### What's the difference between a feedback sign and a speed camera?

A driver-feedback sign shows a driver their speed to encourage voluntary compliance — no citation. A speed camera captures violations for documentation or ticketing. Many agencies start with feedback signs and reserve cameras for persistent problem spots.

### Can the sign show a message, not just a number?

The full-matrix "FM" models (EV12-FM, EV15-FM, EV18-FM) can display programmable text and symbols — "SLOW DOWN", a frown/smiley, or custom messages — in addition to the measured speed.

## Shop radar speed signs

-   [Speed Radar Signs](https://www.solarthingz.com/collections/speed-radar-signs) — the full driver-feedback range
-   [11″ "Your Speed" Radar Sign](https://www.solarthingz.com/products/11-your-speed-solar-powered-led-radar-speed-sign) — the classic entry model, $2,700
-   [SP100 Radar Speed Sign](https://www.solarthingz.com/products/led-solar-power-radar-speed-sign) — solar or AC, $2,975+
-   [SP550 Variable Speed-Limit Sign](https://www.solarthingz.com/products/solar-powered-variable-speed-limit-driver-feedback-sign) — feedback + changeable posted limit
-   [Solar Flashing Speed-Limit Signs](https://www.solarthingz.com/products/5mph-speed-limit-sign) — 5–35 MPH, $900
-   [Speed Management & Driver Feedback](https://www.solarthingz.com/shop/speed-management-driver-feedback) — the whole calming toolkit

Speccing a corridor, campus or district-wide program? The companion guide to [choosing solar flashing, school-zone & radar speed signs](https://www.solarthingz.com/guides/choosing-solar-flashing-school-zone-signs) shows how radar fits the broader active-warning ladder, and the [solar flashing beacon guide](https://www.solarthingz.com/guides/solar-flashing-beacon-buying-guide) covers the beacons that often go with it. Ready for a quote? [Contact us](https://www.solarthingz.com/contact) with your locations, posted speeds and quantities.

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