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Frequently Asked Questions

 

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Operational Range Questions
What determines range?
How can optimum range be achieved?
What periodic system maintenance would you recommend?
Do colored lenses affect range?

Trouble Shooting Traffic Signal Preemption Systems Questions
How do I determine whether the problem is my transmitter or the traffic signal detector?
How can a strobe head be tested to determine whether or not it is faulty?
Compatibility Questions
Will Priority Green work with 3M Opticom and Tomar Strobecom detectors?
Will Priority Green work with encoded detectors (receivers)?
Are there any negatives to preemption-equipped intersections that are programmed for
"Restricted Access" (meaning that only custom-encoded transmitters can activate them)?

Does Priority Green offer any traffic signal detectors (receivers), phase selectors, or
discriminators, at this time?

Will the use of Priority Green void other manufacturer’s warranties?
Is Priority Green mechanically and electrically compatible with my vehicle? With my
lightbar?

General Questions
What is the difference between "Low Priority" and "High Priority" preemption?
Why is it necessary to execute a "Sale Agreement"?
What are the state laws regarding the use of preemption transmitters?
What is that white flood lamp on the traffic signal?
Is optical traffic signal preemption better than audio (siren-based) or radio-based
systems?

Questions about the MicroTube ExtremeRange (MTER)
Mounts anywhere? Will it fit in the lightbar, grill, engine compartment, glove box, under the dash, under the seat, in the trunk, above the visor?
What is the ExtremeRange mode?
If the ExtremeRange mode doubles the power to the strobe head, is the range also doubled?
Does the ExtremeRange mode reduce the operational
life of the strobe emitter?
Questions about the Mobile Preemption Emitter (MPE)
Can I use the MPE in a moving vehicle?
Must the MPE be pointed directly at the detector?
What battery life can be expected?
Can I use rechargeable batteries?
Is the MPE also a flashlight?
How does the MPE work?
Is the proprietary module replaceable?

Operational Range

What determines range?
Priority Green, 3M Opticom, and Tomar Strobecom traffic signal preemption are optically-based communications systems. There are three major factors that determine range in any optical system: the transmitter (power supply and strobe head located in the vehicle), the detector (also known as the “receiver” normally located on or near the traffic signal), and the optical medium between them (air). In a perfect world, the transmitter is working perfectly and the lens covering the strobe head is perfectly clean; the detectors sensitivity is optimally set, the detector’s lens is perfectly clean, and the traffic signal electronics are functioning correctly; and there is no visible obstruction between the transmitter and detector, no fog or bad weather. It is reasonable to expect any working “system” to function properly at a distance of 2500 feet between the vehicle-mounted transmitter and the traffic signal detector. The most common circumstances reducing range are as follows:

Transmitter: Dirty lens, electronic failure of the power supply, faulty strobe head, insufficient power supply input voltage, and faulty cables and/or wiring harnesses can decrease or prevent a system from working properly.

Detector: Decreased range or system failure can be caused by a dirty lens, electronic failure of the preemption detector or traffic signal electronics (damage due to lightning, circuit component failure, etc.), power outage to the intersections, improper sensitivity settings, improper aiming of the “telescopes”, improper mounting locations, or detectors which have been pre-programmed to only permit vehicles that can transmit encrypted ID optical signals (Note: See “Will Priority Green work with encoded detectors?” for specific information related to encrypted ID optical signals)

Medium: The line-of-sight between the transmitter and detector can be compromised by fog, smog, snow, rain, sleet, hail, dust, wind (detectors mounted on suspended lines can sway and/or rock in the wind, interrupting the line-of-sight), or any combination of the aforementioned. The line-of-sight can also be obstructed by other vehicles (notably large trucks), large traffic signs, overpasses (normally due to improper location of the detector, which can often be corrected by either relocating the detector or adding another detector), or any non-transparent physical obstruction.
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How can optimum range be achieved?
System range optimization is a balance between the user’s needs and the preemption equipment’s capabilities. For instance, if the equipment used claims a line-of-sight operation up to 2500 feet, yet your requirement is 3000 feet, then no optimization on the part of the user will overcome the product’s limitations. Physical obstructions that cannot be resolved by relocating the detector (receiver) or adding another detector can also not be improved upon. It is assumed that the reader has established that the system is, in fact, working, although the range has been determined to be substantially less than stated in the product specifications bulletins.

Assuming an unobstructed line-of-sight between the transmitter and detector of 2500 feet, clean transmitter and detectors lenses, and that both electronic systems are fully operational, suggestions for improving the range of any intersection are as follows:

Make certain that the detector is mounted and aimed properly (refer to the manufacturer’s product manuals).

Make certain that the strobe head on the vehicle is not optically occluded (obstructed or partially blocked), and relocate if necessary.

Make certain that the supply voltage to the preemption power supply in the vehicle complies with the manufacturer’s specifications (refer to the manufacturer’s product manuals).

Increase the sensitivity of the detector (refer to the manufacturer’s product manuals).
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What periodic system maintenance would you recommend?
Because the majority of the Priority Green customer base belong to the emergency response sector, most readers are primarily limited to vehicle maintenance and, at best, requesting service for traffic signals that are suspected to be faulty. Maintaining the transmitter is generally limited to periodic cleaning of the strobe head lens (routine car washes), replacing aging and/or defective strobe heads, and ensuring that the transmitter power supply is receiving the proper input voltage when the vehicle is under heavy electrical load (i.e., engine running, all emergency lights “on”, etc.).

The detector (receiver) lens should also be cleaned on a regular basis. Road dust and dirt can and will collect on the lens of even the best-designed product. Traffic signal detectors should be tested frequently, particularly during the warm weather months when thunderstorms are more common. Nearby ground strikes can and will damage even the best protected electrical apparatus.

Safety Alert! NEVER “assume” that a preemption-equipped traffic signal is operating properly! The Confirmation Light (high intensity flood lamp that is often located near the detector on the traffic signal to alert the emergency vehicle driver that he has gained control of the intersection) may not be illuminating because the detector isn’t working!!! ALWAYS PROCEED WITH CAUTION!!! NEVER “ASSUME” THAT THE CONFIRMATION LIGHT IS BURNT OUT!!!
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Do colored lenses affect range?
Yes. Colored lenses do affect range, however the reduction in range is often unnoticeable.
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Trouble Shooting Traffic Signal Preemption Systems
(applicable to any system, any manufacturer)

How do I determine whether the problem is my transmitter or the traffic signal detector?
Priority Green offers a low-cost handheld transmitter/detector analyzer, the MPE (Mobile Preemption Emitter ). The MPE can be used to rapidly diagnose potential problems affecting any preemption transmitter or detector.

Short of the Priority Green MPE, the simplest method is to first test the vehicle-mounted unit at several different preemption-equipped traffic signals. During low volume traffic periods and with clear weather, approach the various intersections at very slow speed (5 mph or less) from a distance of one-half mile. Once the Confirmation Lamp has illuminated, estimate or measure the distance between the vehicle and the traffic signal under test. If the transmitter fails to activate any preemption-equipped traffic signal, or the range (distance between the transmitter and detector) is extremely limited, the transmitter can be assumed to be faulty. If, however, the transmitter successfully activates preemption-equipped traffic signals, but not others, then it can be reasonably assumed that the traffic signals that failed to respond have defective preemption detectors.
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How can a strobe head be tested to determine
whether or not it is faulty?

Unless actual physical damage (i.e., cracked or broken tube glass) has taken place, most strobe heads will not just suddenly cease to flash. Strobe heads (strobe lights, strobe tubes, strobe emitters, etc.) are generally rated for a specific number of flashes at a specific power level by their manufacturers. This “life expectancy” is only an estimate, and can be decreased by high operating temperatures, excessive power delivered to the head, or any dissipation of the inert gas within the tube.

An intermittent or failing strobe head has a tendency to flash erratically, often at a noticeably lower brilliance than a new strobe head. Unfortunately, an erratic or less brilliant flash will absolutely affect the range and operation of any preemption system or product.

Always replace faulty or defective strobe heads as soon as possible.
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Compatibility

Will Priority Green work with 3M Opticom and
Tomar Strobecom detectors?

Yes. All Priority Green products are compatible with 3M Opticom and Tomar traffic signal preemption detectors.
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Will Priority Green work with encoded detectors (receivers)?
Preemption-equipped traffic signals that are programmed to only respond to custom-encoded preemption transmitters will not work with any Priority Green product at this time. However, the actual percentage of preemption-equipped intersections that only respond to custom-encoded transmitters is very small.
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Are there any negatives to preemption-equipped intersections that are programmed for “Restricted Access” (meaning that only custom-encoded transmitters can activate them)?
Yes. Priority Green does not offer transmitter ID encryption of its devices at this time due to the logistical problems and liability often created where such systems are deployed. If a preemption-equipped traffic signal is programmed so that it permits access only to predetermined vehicles, every single traffic signal within the territorial boundary of the equipped emergency vehicle must be similarly equipped. The programming of traffic signal preemption detector electronics is almost never performed by the departments who must make use of them, making the logistics of maintaining such a system cumbersome, impractical, and very expensive - particularly when new vehicles are equipped with transmitters and every traffic signal must then be programmed to accept the new vehicles - logistical responsibilities that responding departments cannot directly control. Liabilities arise when bordering departments, which may have vehicles equipped with preemption transmitters, cannot gain access to encrypted intersections or, worse, when it is “assumed” that access can be gained, creating a potentially high risk situation because the responding emergency vehicle driver believes that he/she has control and right-of-way through the intersection.

Priority Green promotes the spirit of cooperation between neighboring communities, and does not support any product, system, or legislation that mandates traffic signal preemption encryption for any other purpose than “Low Priority” mass transit applications. The concept of “restricted access” does not meet the general public’s needs if it fails to allow control of emergency response personnel through preemption-equipped traffic signals, or puts those same emergency response personnel at risk because they may be unaware that a given intersection is programmed for “restricted access” only.
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Does Priority Green offer any traffic signal detectors (receivers), phase selectors, or discriminators, at this time?
Priority Green does not offer detectors (receivers), phase selectors, or discriminators at this time. All Priority Green products are compatible with 3M Opticom and Tomar traffic signal preemption detectors.

Priority Green strongly recommends the use of 3M Opticom detectors, phase selectors, and discriminators, as the Company believes the history, quality, and success of this product line speaks for itself.
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Will the use of Priority Green void other manufacturer’s warranties?
No. Legal precedents have actually been established that prevent marketplace competitors from even threatening to void warranties when competing or interactive devices can not be proven to “harm” the product under warranty.

All Priority Green products are compatible with 3M Opticom and Tomar traffic signal preemption detectors.
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Is Priority Green mechanically and electrically compatible with my vehicle? With my lightbar?
The Priority Green MicroTube ExtremeRange product is the most compact and versatile traffic signal preemption power supply in the world, which means that it can be installed in virtually any location within any known vehicle or lightbar. All products will operate on any 9 to 15 VDC electrical system (select option –28 to increase the product range to 28 VDC), with by far the simplest and least time consuming installation process in the industry.
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General

What is the difference between “Low Priority” and “High Priority” preemption?
“Low Priority” is generally used by mass transit authorities to increase the time duration of green lights or and/or decrease the time duration of cross-traffic red lights. “High Priority” takes precedence over “Low Priority”, and the purpose is to secure control of the intersection by maintaining a single direction of traffic flow by holding the traffic signal green until the emergency vehicle has passed through that intersection. “Low Priority” is generally considered to be 10 hertz (10 flashes-per-second) while “High Priority” is 14 hertz.
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Why is it necessary to execute a “Sale Agreement”?
Priority Green will not sell traffic control products to individuals, companies, or organizations that are not legally authorized to use the devices. The “ Sale Agreement” is a tool used by Priority Green to determine the authenticity of the buyer, and to prevent unauthorized individuals from illegally obtaining the product.
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What are the state laws regarding the use of preemption transmitters?
Laws vary from state to state. To determine your states laws consult your state’s Department of Transportation.
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What is that white flood lamp on the traffic signal?
The “Confirmation Light” is primarily used to “confirm” that the intersection has been accessed by an approaching emergency vehicle. Individual state Departments of Transportation determine when the light actually illuminates, and if it flashes or not. In most instances, the Confirmation Light will remain illuminated (or flash) until it no longer detects the preemption transmitter, which is usually because the emergency vehicle has passed through the intersection.
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Is optical traffic signal preemption better than audio (siren-based) or radio-based systems?
All traffic signal preemption systems have trade-offs, so comparisons should be made based upon cost, operational requirements (range, ease of installation, etc.), and future expectations. However, it should be pointed out that by far the most prevalent traffic signal preemption technology is optical.
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MicroTube ExtremeRange

Mounts anywhere? Will it fit in the lightbar, grill, engine compartment, glove box, under the dash, under the seat,
in the trunk, above the visor?

Yes, it will mount in all of these locations. The compact design of the MicroTube has been engineered to fit in tight locations that have previously not been capable of housing a preemption power supply. The MicroTube is also a rugged waterproof product, easily withstanding the hostile environment of an engine compartment or the greenhouse-type heat of a lightbar on a hot summer day.
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What is special about the ExtremeRange mode?
The ExtremeRange mode is especially attractive to the law enforcement community. A police cruiser traveling at an extremely high rate of speed needs all of the distance it can get when it comes to preempting traffic signals - the greater the speed of the vehicle, the less time it takes to cover a fixed distance. A vehicle traveling at 100 mph will cover approximately 150 feet per second. Therefore, the 12 seconds (or less) that it would take to descend upon an intersection that can normally be accessed from 1800 feet out might not be enough time for the traffic signal to cycle into the preemption mode, clear the traffic, and safely pass through the intersection. The ExtremeRange mode preempts the light at distances up to 2500 feet.
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If the ExtremeRange mode doubles the power to the strobe head, is the range also doubled?
No, but depending upon the type of strobe head being driven, the increase in range can be significant - it could be the difference between sitting in traffic at a red light or preempting the traffic signal to your advantage. At a minimum, several hundred feet of additional range can typically be expected.
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Does the ExtremeRange mode reduce the operational
life of the strobe emitter?

Here’s a better question: does a user-controllable feature that enables a traffic signal to be accessed from a greater distance, and therefore possibly saving time and lives, make the possibility of limiting the life of the strobe emitter worthwhile? Yes!

The more power delivered to a strobe emitter, the shorter its operational life (with respect to the number of times that it can be “flashed”). This holds true for any strobe emitter. The ExtremeRange mode does deliver more power to the strobe emitter, although in most cases the reduction in operational life will be negligible.

The ExtremeRange may reduce the life of your strobe. But the knowledge that you have the option of additional range, if and when you need it, might one day save a life.
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MPE (Mobile Preemption Emitter)

Safety Alert! This product is not to be used in a moving vehicle under any circumstances!!!

Can I use the MPE in a moving vehicle?
The MPE will not work effectively from a moving vehicle. The product has been intentionally designed to be range-limited, and holding the device steady in one’s hand while driving is virtually impossible.
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Must the MPE be pointed directly at the detector?
The MPE need only be pointed in the general direction of the detector on the traffic signal.
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What battery life can be expected?
While any standard “D” cell batteries will work, Priority Green recommends the use of industrial alkaline “D” cell batteries. Assuming the product is used several times each week for approximately 15 minutes per use, the batteries can be expected to last many months.
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Can I use rechargeable batteries?
The use of rechargeable batteries is not recommended. The voltage-per-cell of most rechargeable “D” batteries is only 1.2, compared to the 1.5 volts of alkalines. The lower voltage of the combined rechargeable batteries (4.8 volts verses 6.0 volts) results in reduced light output and range.
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Is the MPE also a flashlight?
The MPE should not be used in place of a flashlight, nor does it function as a flashlight.
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How does the MPE work?
The MPE contains a proprietary circuit that is epoxy encapsulated. This circuit first takes the 6.0 volts supplied by the four “D” alkaline batteries and coverts it to two separate higher voltages: 400 and 6,000 volts. The 400 volts is developed and stored in a capacitor, and 14 times each second a microcontroller sends a signal that triggers the flashtube (with the 6,000 volts), and this discharges the storage capacitor into the tube, creating the stroboscopic white light.
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Is the proprietary module replaceable?
Yes. Return your MPE to our factory for replacement or repair. The flashtube itself is also factory-replaceable.
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