You are about to initiate a nighttime traffic stop. Subconsciously you are simultaneously considering your own safety and the safety of the driver. You start the process by picking a safe spot to pull the driver over. Then you begin to look for any suspicious movements and or activity in the suspect vehicle. Next comes the call out and the activation of your equipment and you begin to position your patrol vehicle according to department policy and or your personal preferences.

Traffic stops are second nature to most patrol officers but even the most routine activities become more complex when executed in diminished light. Let's review nighttime traffic stop safety procedures that you should know and then we'll look at some additional considerations that can help increase your safety during a nighttime traffic stop.

Vehicle Placement

In 2002 Ford Motor Company and the National Highway Transportation Safety Administration (NHTSA) developed a best practice recommendation for vehicle placement based on computer simulations and real world application/testing. Unfortunately, many departments by policy require vehicle positions on traffic stops that limit suspect vehicle illumination and ultimately put officers at a distinct disadvantage, especially during nighttime traffic stops.

Ford and NHTSA concluded that the safest position for stopping a vehicle is to move the stopped vehicle off the roadway as far from moving traffic as possible. If that is not possible and if the officer has chosen the offset left position for stopping a vehicle, the best protection for a pedestrian officer while he is at the stopped vehicle's driver side door is to position the vehicle according to the rules set forth in the acronym STOP:

• Space the vehicle about one car length away

• Turn the steering wheel to the right

• Offset your vehicle with the stopped vehicle 50%

• Parallel the road

Use Your Lights

Now that we've discussed how to have the subject vehicle pull over and where, let's look at how to use your lights to your tactical advantage.

Use your high beams, spotlights, and takedowns to light the entire subject vehicle. You are creating a "Wall of Light" that will overwhelm the occupants of the subject vehicle with intense light that disrupts their ability to see to the rear.

Set the spotlights up to match your preferred vehicle position. If you have only one spotlight on your patrol car it should be pre-set so it requires minimal adjustment to illuminate the interior rearview mirror of the subject car. If you have two spotlights, aim the passenger side light at the interior rearview mirror and aim your side light at the subject car's driver’s side mirror.

The Approach

More officers than you may think have been killed making the second approach during a traffic stop. There are many theories for why officers are particularly vulnerable at this stage of a traffic stop.

• The suspects know that the officers have called in their plates and driver license numbers and now know the suspects are wanted.

• The suspects have had a chance to assess the officers and their tactics and have had time to formulate plans of attack.

• The suspects have had time to build up their courage to assault the officers as they return.

Handheld Lights

Whether it's the first approach or a subsequent approach your tactics must be sound. In particular at night your use of all your lights must always enhance your survivability. This includes your handheld lights.

Whether you choose a passenger side approach or a traditional driver’s side approach, the way you use your handheld light can mean the difference between a safe traffic stop and a disastrous one.

The passenger side approach is an option you should add to your tactical toolbox. Although it’s not always appropriate or even possible because of the location or circumstances, the passenger side approach keeps you farther away from the traffic flow. In addition, most drivers expect you to approach on the driver's side. So suddenly appearing on the passenger side can afford you the element of surprise and a much better view of what is taking place in the vehicle.[PAGEBREAK]

The impact of alignment on illumination is significant. Just 24 inches off centerline substantially reduces the light.

Utilizing the Wall of Light you established as you initiated the stop, approach the vehicle from the rear of your car. Do not cross between the vehicles. As you approach the vehicle have your handheld light ready to switch on but wait until you are positioned for the best tactical advantage before you light up the occupants of the vehicle.

Now let's discuss the driver's side approach. This is by far the most common method used today. For some officers it is the only way they ever approach, although I would encourage everyone to have more than one technique in their arsenals for any law enforcement-related task, including vehicle approaches.

On a driver's side approach, the driver's side mirror is often an aiming point for my handheld light, especially when the patrol spot is aimed at the interior rearview mirror. The majority of the time this technique will result in complaints from the vehicle's occupants, but it will allow you to gain a small advantage while more clearly assessing the vehicle's interior. A simple apology about not realizing you aimed the light into the vehicle will often be met with the occupant saying, "No, you didn't shine it in the car. It reflected in the mirror."

Understanding Light

Now that we have reviewed the basics, let's try to understand why light is so critical to our overall survival and learn how to better deploy low-light techniques on future traffic stops.

There seems to be a lot of confusion as we discuss light power/brightness. Most modern flashlights are rated in lumens. A lumen is a way of measuring how much light gets to what you want to light. One lumen is equal to one foot-candle falling on one square foot of area. A foot-candle is how bright the light is one foot away from the source.

Candlepower and a foot-candle unit of measurement are not the same. Candlepower is a measure of light taken at the source of light, not at the object being illuminated. Foot-candles measure the light directed at the object being illuminated.

On a traffic stop, our headlights are our primary method of seeing at night, but the benefits of these lights can be very limited. The angle from the center of the light beam and the distance the object is from the light source are critical factors.

Look at the chart above and note the light meter readings taken at 5, 10, 20, 40, and 50 feet from the headlight surface of a 2012 Dodge Charger patrol unit. The second set of measurements from the same distances but just 24 inches off the centerline of the beam are significantly lower than the centerline results.

This is important for many reasons. The first being how it relates to the distance between the subject vehicle and your unit. Consistency on your part here will result in similar light conditions and ultimate visibility with each stop. The drastic drop in light illumination as measured off the beam's centerline is critical to the vehicle's offset when you position the unit. So is knowing this drop in illumination can be an asset on the approach and while maneuvering around the vehicles.

The Wall of Light you have established has many advantages if your vehicle is properly positioned. Proper vehicle position and your approach technique will limit your body silhouette as you approach.[PAGEBREAK]

Without the proper lighting, you may be buying a load of trouble. The man on the left is pointing a cell phone. The one on the right is pointing a pistol.

Contrast and Movement

The above diagram shows the dramatic reduction in the amount of subject illumination as the distance from the source increases. We need to understand how contrast and movement impact our ability to identify objects and actions and our decision-making process.

Mistake-of-fact shootings happen in all environments and traffic stops are no exception. In one of the above photos the subject is standing 40 feet from the light source and pointing a cell phone. In the other photo, he is pointing a Glock 23. Given a split-second to make a determination it is easy to see how the subject’s movements will have a huge impact on our ultimate interpretation of what we observe.

I often refer to this as "visual patience." We must work at developing our visual patience whenever we are deploying light. The mind's eye wants to fill in the blanks, and when our eyes can't see some specific detail, the mind wants to complete the picture, which can easily mislead us to a mistake-of-fact shooting.

An example of contrast is represented in the photo above. In an effort for clarity, I chose the extremes in contrast white and black. You can imagine how correct interpretations become more difficult when looking at the contrast between brown and tan or gray and silver, just to mention a few. The subject in these pictures is standing 40 feet from the light source with a Glock tucked into his pants.

Light and Vision

There are no routine traffic stops. We all understand that anything can happen at any time. When we add darkness to this equation even the simple becomes more complex. If we understand how our bodies and minds react to the absence of light we can adjust our tactics to our advantage.

Our eyes react differently to various light conditions. There are three types of vision that relate directly to ambient light conditions: photopic, mesopic, and scotopic.

Exposed to higher levels of light, we use primarily the cones of the eyes. This is called photopic vision. Photopic vision is categorized by our ability to determine color and detail and a lack of light sensitivity. In low-light situations we rely primarily on our rods, and this is called scotopic vision. Scotopic vision limits our ability to determine color, but we tend to pick up movement and of course our eyes are very sensitive to bright light. The last and more complex condition is mesopic vision, which uses the bottoms of the cones and the tops of the rods. Mesopic vision typically is encountered when we are exposed to street lights, parking lot lights, and traffic headlights. During mesopic vision, we are in between full reliance on rods or cones and therefore what we can see depends on which is most dominant based on the true light level.

It is clear to most of us that we adapt to light much faster than to darkness. When we transition to a darkened environment it takes about 30 minutes to transition completely from the cones to the rods. In contrast we can complete the transition from dark to light in less than two minutes.

Using light to control your subject during a nighttime traffic stop is very important. How often have you heard, "Watch the hands; it's the hands that are going to hurt you?" I recommend that when necessary you keep the light hotspot in the eyes of your subject. You will have enough light to see the hands, but you will be in control of the subject. Not only will the subject be disoriented, but he or she will not be able to assess you, look for weapons of opportunity, and perform other tasks necessary to attack you.

Take the time to learn how to use your equipment to your advantage. Develop consistencies in how you do your job. Do not let traffic stops become a routine, especially at night.

Edward M. Santos is the owner and founder of Center Target Sports and an expert in low-light tactics.