The University of Kansas’ Dr. Eric Meyer related, “The radar display was quite effective, reducing mean speeds, 85th percentile speeds, and the percent of drivers exceeding the posted limit.” Dr. Geza Pesti, Department of Civil Engineering, University of Nebraska, conducted a long-term study on large digit, LED numeral speed displays. He found the “percentage of passenger and nonpassenger cars complying with the speed limit increased to 91 and 90 percent respectively” with the use of high visibility speed displays. He also found “it was equally effective day and night, with even greater effectiveness at night because of its greater nighttime visibility.”
The city of Phoenix at the Greenway Road location, the 85th percentile was reduced from 47-48 mph to 14-16 mph with the radar display in operation in the 15 mph school zone. At the 19th Avenue location, 85th percentile speeds were reduced from 32 mph to 25 mph, after the 3M display was operational.
SML conducted long-term radar display, not trailer, research in three Texas communities – Marshall, Del Rio, and El Paso – to see if the speed reductions would fade with time. This is called a “halo effect.” There’s always someone who flatly claims, without research, “They may work the first week you put them up, but, after some time, people will disregard them.” SML found one day after installing speed displays that Marshall had a school zone speed limit compliance rate of 69%; El Paso was at 72%. One month after placement, The Marshall Messenger (November 29, 2000) reported 73% compliance and the El Paso Times (August 18, 2000) confirmed 73% compliance. These data clearly show long-term effectiveness. The Taos News (New Mexico) reported (January 24-30, 2002) that before a speed display was placed in a problem neighborhood, only 13% obeyed the 30 mph speed limit. After placing a pole mounted speed display, 86% respected the speed limit. Houston’s El Dia newspaper conveyed similar results. In their January 24, 2002, issue, El Dia related only 10% of vehicles were driving the 20 mph school zone limit before placement of a pole speed display. Afterwards, the compliance rate rose to 85%.
Keep in mind that the faster the traffic is traveling, the larger the display must be for motorists to see the display and respond to it. In instances when federal money is being used to purchase equipment, the radar display must comply with MUTCD (Manual on Uniform Traffic Control Devices) regulations, ie., the numerals must be either lime green or yellow and the case should be white – not red or amber! However, many aspects of the MUTCD are open to interpretation and vary according to the type of system. The federal government has long promised clarification regarding radar displays. Presently, U.S.D.O.T. does not issue letters of compliance to any vendor of trailers or displays and the final clarification looks years away. Find out if the system you are considering fits the guidelines of your city and state traffic control regulations. If you use local money, it’s your call.
It’s best to invest in current direction sensing radar technology. Direction sensing means the radar will only show the speeds of approaching vehicles. You want approaching drivers to see their speed and not the 18-wheeler going away. Do not use X-band radar trailers/displays. Fifteen percent (15%) of drivers own a radar detector. They disregard X-band warnings as false alerts coming from supermarket automatic door openers, burglar alarms, and other sources.K- and Ka-bands are essentially devoid of such false alerts.
Powering is the big headache with trailers. They are powered by batteries or with a solar assist. Although some solar assisted units can be fully independent when used in places such as Florida or Arizona, most solar panels can not independently power a radar trailer.
The amount of power needed ultimately depends on the requirements of the unit itself; some simply need more power than others. In most models, you must recharge the batteries at regular intervals. If you forget, you’re out of juice. After the initial excitement of getting a radar trailer, usage normally wanes because of powering and cumbersomeness. If it breaks, how do you get it fixed? It’s not like your Crown Vic with a nearby Ford dealer.
Radar displays are becoming an attractive, flexible alternative to radar trailers. For the price of one radar trailer, you can buy three to four radar displays. Many speed displays can be powered by either AC or DC automatically. They can be mounted on exiting AC poles, completely powered by a solar panel/battery combination or powered by a police vehicle. ccc
One of the best applications comes from Blaine, Minnesota. Lt. J.M. Miller reports great success with speed displays used by the city. Blaine erected 46 poles at 23 locations throughout the city where community speeding was a problem. The speed displays are rotated among them on a regular basis. They are powered by two batteries. Lt. Miller reports, “Citizens have been very positive about the speed displays. When we rotate them from pole to pole, homeowners come out and plead with us to leave them where they are in front of their house. Speed reductions have been substantial. We intend to buy more. We have used them for a year and have had one incidence of vandalism.”
Chief Lanny Maddox, Ruidoso, New Mexico, Police Department, installed two speed displays in the town’s shopping district in 1996. Chief Maddox related, “It’s probably the best investment I ever made. Speed limit compliance is approximately 97%. People don’t realize how fast they’re going and the radar displays get their attention. With the solar panel continually charging the batteries, we have never had an electric bill. I am recommending to the council that we buy more.”
Sheriff Arvin West, Hudspeth County, TX, oversees law enforcement in a county measuring 5,780 square miles. The county is dotted by many small communities.The county seat of Sierra Blanca has the last all adobe courthouse left in the nation and 800 citizens. Hudspeth County is enormous, wide open spaces dissected by Interstate 10 which results in a serious speeding problem. In August of 2001, the county saw 15 traffic deaths. Sheriff West says, “One out of every three cars in our school zones was speeding. We have limited resources and needed a truly portable speed display we could easily move around. We bought a speed display. We attach it to existing school zone poles and also on our patrol cars. We even use a DOT stand with batteries. It has greatly reduced speeds.” County Commissioner Pilar C. Ortega echoes Sheriff West’s comments. Commissioner Ortega states, “The people love it. It multiplies our law enforcement efforts and placing it in one of our school zones is just like having an officer there. I have not had one negative comment from any citizen.” Some communities have initiated the tax deductible “Adopt a School Zone” program soliciting funds from companies, individuals, and organizations to pay for the speed display. This is much like the popular “Adopt a Highway” system. Donors have their names attached to poles next to speed displays.
Field experience tells us that speed displays should have several capabilities. They should offer a 24/7/365 timer when used in school zones. This allows operation only when school is in session. The radar’s reporting range should be adjustable. It serves no purpose to have radar report a speed from one mile away or a vehicle located in an adjacent shopping center parking lot. It should report speeds as drivers enter school zones or other controlled locations. The narrower the radar beam, the better. Ka-band has the narrowest beam, while X-band is immense!
Some speed displays have a flashing strobe and flashing numerals when an approaching vehicle exceeds the speed limit. When the vehicle comes into compliance, the flashing stops. This is called “Violation Alert” and is a proven feature. Speed displays should have “Maximum Speed Cutoff.”When set at 80 mph, the speed display will not show speeds above the setting. If desired, speed displays should show approaching vehicle speeds while attached to a moving patrol car
Sarge knows both radar trailers and radar displays are effective, but which one to buy? Radar trailers seem like a good choice because you can tow them around. They are three times the cost of radar displays, but mobility is important. Wait a minute, Sarge! Let’s look at experience talking. First, is it legal to operate radar trailers/displays? Drone Radar Operational Guidelines (U.S.D.O.T. HS #807 753) allows the legal operation of radar trailers/ displays. You also have an implied RS Radiolocation CFR 47 license to operate radar as part of your commercial police radio license. Although radar trailers seem to be flexible, sometimes, they’re not. You have to dedicate one unit to transport and maintain the trailers. Many times, where you want to place it doesn’t allow enough space. They are heavy and cumbersome! If you have only one trailer, everybody wants to use it.
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