Choosing the right radar speed display for your community

Oct. 1, 2008

     Radar speed displays have become the technology of choice for a growing number of law enforcement professionals looking to slow traffic. In a national survey of police officers, traffic engineers and corporate safety officials, the displays were identified as the single most effective traffic calming solution near schools, playgrounds and neighborhood streets. More than speed bumps, stop signs or even police with radar guns, radar speed displays were ranked as the preferred means of slowing speeders and keeping average driving speeds down in the long run.

     A number of factors have led to the adoption of radar speed displays — from a growing base of statistical findings that prove their effectiveness, to advancements in the technology itself. As features, designs and technologies evolve, so does the disparity between various styles and brands. A review of these differences and a look at specific issues for consideration will help ensure that the right equipment is used.

MUTCD compliance

     If you are installing a traffic control device on a public street or highway, chances are the equipment must meet requirements of the MUTCD (Manual on Uniform Traffic Control Devices). The Federal Highway Administration's MUTCD sets the standards for size, shape, dimensions, content and color of displays for use on all federal roadways, and most states and municipalities have adopted the MUTCD standard.


     Radar speed displays are designed to communicate messages and alert speeding drivers in many different ways. The "Your Speed" message often remains static while the driver's actual speed is displayed when the car approaches, and some signs can be set to flash the actual speed number when the driver exceeds a predetermined limit. Others display a "Slow Down" message at a pre-set threshold.


     Pre-scheduling changes to the signs' functions can be a huge savings in time and cost. Signs that automatically change their posted speed limit take the guess work out of legal driving speeds in school zones, along carpool lanes and locations where the limit changes depending upon the time of day.

     The scheduling capabilities of various electronic signs differ. Some may not have any scheduling capabilities, while others may allow multiple changes depending upon the time of day or day of the week. Features may allow scheduled speed limit changes, scheduled use of accessories such as flashers, scheduling speed limit thresholds (the speed that needs to be exceeded before the display switches to a message or turns off), or scheduled message changes.

Beyond speed

     Some radar speed displays allow users to collect data regarding traffic flow, such as the total number of cars using the street, average speeds at any given time of day, number of speeding cars, etc. This can provide the raw data needed to prove that an existing speeding problem exists, and validate the overall effectiveness of the display.

     As valuable as advanced scheduling and data collection may be, engineers are finding that they often remain unused if signs are difficult to set, monitor or access. To address this, some manufacturers incorporate wireless connectivity options in their signs. Wireless options range from simple handheld devices that provide close-range connectivity to full cellular remote-office capabilities.

     Handheld devices let users download collected data or change features from the comfort of their car. This has proven to be a significant improvement over models that require the manual manipulation of the sign itself. Instead of having to open up and access an interior control panel in order to collect data or set features, the wireless devices allow simple drive-up connectivity, download and scheduling.

     Signs with remote office accessibility have recently been introduced onto the market. With this, city safety experts can use an office PC to monitor and control any number of signs from a single remote office location. The built-in cellular technology can synchronize multiple signs to ensure uniform operations.

Power options

     Radar speed displays require a power source. This can mean A/C or battery power, or solar energy; the right choice typically comes down to cost and flexibility.

     The energy cost of operating a radar speed display is relatively low; about the same as running a night-light. However, the sign's installation and maintenance cost can be significant.

     Gaining access to A/C power may require running wires beneath existing streets. If the sign is to be mounted near an A/C power source, it's possible to tap into that power; typically the utility company allows you to pay a flat rate for the sign's energy consumption. Sometimes, the utility requires that meters be installed in order to measure the amount of energy being used.

     To address applications where A/C power is cost-prohibitive, some models offer battery-powered functionality. While these signs may cost less to install, they typically require maintenance. Batteries require constant recharging — typically every two weeks. And battery life is usually short, so replacement costs must be considered.

     Given the potential drawbacks of A/C and battery-powered signs, many users are opting for solar-powered units. Thanks to reduced power consumption, fewer panels are required to operate the displays, thereby reducing the price of solar powered signs dramatically.

Design considerations

     Design variations also should be considered when choosing the right radar speed display, as different lights and accessories can affect the amount of energy required to operate the sign. The moving parts in flip-style electro-mechanical displays are more susceptible to wear and damage than LED signs, and may also require more electricity to operate. The size of the display's messaging can differ, too. Fifteen-inch lettering is often preferred over 12-inch versions.

     Finally, high contrast enhancement technologies and advanced glare management techniques can improve sign visibility while reducing the amount of power required, resulting in clearer electronic lettering. The type of lighting and the way that the LEDs are set into the face have an impact on overall effectiveness as well.

     Every agency's goal when shopping this type of speed control unit is to find a product that's effective, efficient and safe to use on the streets.

     John Dixon is a Portland, Oregon-based business writer who focuses on traffic, safety and new technology.

A brief overview of products offered by three major manufacturers:Information Display Company (IDC)

     According to an IDC spokesperson, the company's SpeedCheck radar speed signs are used in more U.S. cities than any other brand. The signs incorporate a variety of patented technologies designed to increase display visibility (UltraClear), maximize safe use (SafetyMask) and thwart vandalism. The units permit the added use of accessories such as flashing lights and come in A/C, battery-powered or solar-powered configurations.

Radarsign LLC

     Radarsign is headquartered just outside of Atlanta. Radarsign makes three basic models: A/C powered, rechargeable battery powered and solar powered units. The company touts its products' rugged, vandal-resistant features, including its Bashplate design, which is constructed to withstand severe abuse.


     In 2000, 3M purchased American Electronic Sign, a company that first began manufacturing electronic signs used for advertising. Over time, the company has leveraged this purchase to become a major player in, among other areas, the variable speed control (VSC) display industry.

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