Police Department Preemption

The Eliminator Emergency Vehicle Preemption (EVP) System provides specific features designed for Police Departments. Most EVP systems use ETA or GEO windows to define when or where preemptions occur. However Police Apparatus typically travel at a higher rate of speed than Fire and EMS, specifically faster than the larger vehicles such as Engines, Tankers, and Ladder Trucks. Therefore optimal settings used for a Fire Engine that travels 40 mph will not be optimal for a Police Apparatus traveling as high as 70 or 80 mph. Seemingly ETA should equalize these two vehicles, however the traffic signal takes a fixed amount of time to cycle to a green light and civilian traffic takes a fixed amount of time to react therefore reducing the impact of using ETA. GEO Windows are even less flexible in that they will always preempt at exactly the same place.

The Eliminator provides several features that are key to optimizing preemption performance for all departments and vehicles. 

  • Preemption settings can differ by department, therefore allowing the police department to have different settings tailored to their vehicles that travel at a higher rate of speed and are more maneuverable. 
  •  Each department gets two classifications of preemption settings. One for light duty vehicles (typical first response vehicles) and one for heavy duty vehicles that are larger, travel at a slower rate of speed, and are less maneuverable.

With other preemption systems one common complaint is that the preemption route can be “over driven”, which means if you drive too fast you will drive faster than the system can respond. This is an obstacle caused by several factors:

Other low range systems

Other systems have a much lower radio range than the Eliminator. Other systems have a range of 2,500 to 3,600 feet which is only several tenths of a mile. 

2.4 GHz Radio WiFi based systems are not the solution

Although any Radio/GPS system eliminates LOS issues that exist with Optical based systems and increase range, some systems use 2.4 ghz (WiFi) and therefore only have a max range of 2,500 feet (.47 miles/.76 km). At busy intersections and/or high traffic areas starting the process of changing the light to green 4 tenths of a mile away will not result in a clear intersection. Many times traffic is congested 4 tenths of a mile or more. Traffic lights do not immediately turn green when preempted, first the light in the opposing direction must SAFELY go from green, to yellow, and then finally to red allowing a green light in the preempted direction. This process can take 5 to 15 seconds. Preemption is also not allowed to override pedestrian crosswalk timers which can increase the preamble time further.

Cellular Systems are not the solution

Just as with Radio/GPS based systems, cellular based preemption systems also solve the line of sight (LOS) problem, however these cellular emergency vehicle preemption systems bring a new set of problems.
  • Cellular brings monthly fees. Imagine a coin operated box attached to the signal and every preemption having a cost. More specifically and costly, every communication, resulting in a preemption or not, will have a cost. 
  • In large emergencies (mother nature, terrorism, etc.) the cellular network always go down. So when you need your preemption the most it will not be functional. 
  • Are Cellular networks 100% reliable? Anyone with a cell phone knows they are not. From lag/delay to network overload you do not want your green light being dependent on a network shared by everyone else around you. 
  • Although some cellular systems may offer a radio backup, it is just that, a backup. If the radio backup worked well then it wouldn't be the backup. When these systems are proposed in a bidding process they are required to include 10 or even 15 years of unlimited cellular data.
  • Since cellular based preemption lacks precision the preemption timings will not be precise or consistent which degrades performance and benefit. Recently one large city tested a cellular preemption system and found it took up to 10 seconds to release a preemption. This can result in the preemption being held for a tenth of a mile or more after the EV clears the signal.

It is also worthy to note that using 2.4 GHz and Cellular go against FEMA recommendations for Preemption Systems.1.

The Eliminator is the Solution without trade-offs

The Eliminator uses a private 900 MHz FHSS network with a radio range of over 13,500 feet (well over 2 miles/4km) This increased distance allows greater flexibility to proactively preempt the traffic signal in the safest and least disruptive way possible and allows the flexibility to adapt to the different needs of Fire, Police, and EMS including the differences in their fleets. Additionally the Eliminator solves the right-of-way liability issue once and for all.

Additionally the Eliminator allows separate settings for each department and vehicle class. This means the settings that work best for a Fire Engine will not be the same settings used by the typical Police Car, this allows all departments to get optimal response time reduction from the preemption system.

The research overwhelmingly points to the fact that risks, to both the community and first responders, will be reduced after the implementation of an Emergency Vehicle Preemption System at signalized intersections. This reduction in risk can be measured by the reduction in accidents and injuries occurring at intersections controlled by preemption devices.2

Although the Eliminator Preemption System can connect via WiFi, Direct Network (RJ45) and Cellular these connection protocols are only used for management, log retrieval, AVL (Automatic Vehicle Location), and other non-emergency purposes. 

In the field we often hear the concern regarding “abuse” of preemption. This involves using the system to preempt the traffic light while not on an emergency. The Eliminator prevents this abuse via configurable settings. The system can be configured to only preempt when on a hot run and cannot be overridden. Further all preemption's are logged and tracked at the traffic signal and the vehicle. This provides full accountability.

25% of all collisions are at Traffic Signals

Nationwide, over the past 10 years, more than 25 percent of all Emergency Vehicle crashes have been found to occur at signalized intersections.3 These crashes often involve situations where vehicles approaching a green signal cannot see an Emergency Vehicle approaching on the intersecting roadway because of line-of-sight problems with nearby buildings, vegetation, or hills. For these situations, Emergency Vehicle Preemption provides familiar guidance to private vehicles by showing a red signal at the conflicting approaches, thereby bringing these vehicles to an orderly stop. Safety benefits can be measured by comparing EV crash histories or, as a surrogate, by measuring the reduction in the number and severity of conflict points that may be present at the time when an Emergency Vehicle traverses the intersection.4

Modified Emergency Response Policies

A decrease in Emergency Vehicle crashes reduces public liability associated with fatalities, injuries, and property damage. Over the past 10 years, there have been approximately 80 EV crashes each year in the U.S. that involve fatalities.5

As in the fire and EMS services, there exists no national standard or regulations for police agencies about when or when not to respond to calls using emergency driving procedures. While there may be some direction from applicable state motor vehicle codes, most policies that exist on this topic are agency-developed and highly dependent on the culture of each individual department. In many cases, the policies that are in place are not highly specific on when and when not to drive in an emergency response mode. This is because of the perception that every call is a different situation and certain variables may or may not justify an emergency response.

In reality, all law enforcement agencies should have relatively firm policies on what justifies an emergency response and what does not. There must be some flexibility in these policies to account for conditions such as inclement weather, heavy traffic conditions and other factors that may influence the response time. However, in establishing these policies, law enforcement agencies should use a risk versus benefit perspective to determine when emergency driving is appropriate.

One of the critical factors to consider when developing this type of policy is whether there is any likelihood that a slightly faster arrival on the scene of call is likely to make a difference in the outcome of that incident. Many, if not most, incidents that police officers respond to are actually over before the caller even talks to the 911 dispatcher. In those incidents, an emergency response versus a non-emergency response will make no difference in the outcome.6

The International Association of Chiefs of Police (IACP) has developed a set of model policies and procedures that can be adapted by local police agencies for use in their jurisdictions. “The Manual Police Traffic Services Model Policies and Procedures” can be downloaded from the Internet at no charge.7


Eliminator "ON" mode as part of the solution

The Eliminator’s “ON MODE” feature has the unique ability to facilitate such a “modified” or non-emergency response (See Fire Chief Danny Sink Video for more information on and other features). By preempting traffic signals WITHOUT the use of lights or siren, the chances of the apparatus being involved in a collision are dramatically reduced, while the travel time is similarly reduced by 14% - 23%.3 This eliminates excessive out-of-service times that might prevent them from otherwise being available to respond to a true emergency.


U.S. Fire Administration, Emergency Vehicle Safety Initiative, FA-336/February 2014, page 100, Download PDF

Reducing Risk Through the Use of Traffic Preemption, Mark A. Lorenzen, VenturaCounty Fire Protection District, Camarillo, California, page 29, Download PDF

Traffic Signal Preemption for Emergency Vehicles, A Cross-Cutting Study, Putting the “First” in “First Response”, FHWA (2006), page 3-1, Download PDF

Traffic Signal Preemption for Emergency Vehicles, A Cross-Cutting Study, Putting the “First” in “First Response”, FHWA (2006), page 3-1

Traffic Signal Preemption for Emergency Vehicles, A Cross-Cutting Study, Putting the “First” in “First Response”, FHWA (2006), page 3-1

Meet the Firefighter/Engineer that designed our Preemption System.

However, being a firefighter is only half the story, Adam has spent over a decade designing systems for defense contractors that use Radio and GPS. He knew from his diverse experience that existing GPS, Optical and cellular Traffic Signal Preemption System weren't meeting the two most important needs, affordability and performance.

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GPS Preemption Compatible with Optical

Do you already have an Optical Preemption System or Infrared Preemption system or commonly referenced by a brand name such as Opticom ®, Emtrac ®, Tomar ®, Strobecom ® or MIRT ®? Upgrading to a GPS Traffic Signal Preemption System is affordable and simple.

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FireRescue1 Industry Article

Could traffic preemption reduce fire response times and save lives? Once overlooked as expensive and impractical, signal preemption has come a long way since the 1970s

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Fire Departments

As the call comes in and your department is focused on digesting and learning the circumstances of the emergency and the scene while enroute, traffic should not be a major consideration. Today�s electronically distracted drivers have made the opposite even more true. Motorists already respond to the presence of an emergency vehicle differently but often distracted drivers do not react at all.

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Police Departments

The Eliminator Emergency Vehicle Preemption (EVP) System provides specific features designed for Police Departments. Most EVP systems use ETA or GEO windows to define when or where preemptions occur. However Police Cars typically travel at a higher rate of speed than Fire and EMS, specifically faster than the larger vehicles such as Engines, Tankers, and Ladder Trucks.

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From the moment an emergency run begins, there is potential for an even greater disaster; colliding with another vehicle enroute to the scene of the emergency. This often results in that vehicle and its occupant(s) becoming an additional emergency incident to address. Many cities have experienced an increase in collisions with emergency vehicles at intersections, but emergency vehicle preemption has been shown to effectively reduce the probability of these collisions by giving ambulances the right of way.

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