Scanning The Road: SEE Space Management System Stage 1Updated Oct. 25, 2020
The first stage of the SEE system – or indeed any defensive driving strategy – is scanning the roadway to detect potential hazards and upcoming changes, which would require alterations to your driving behavior. This step is crucial, as your ability to make safe driving decisions rests on forming an accurate picture of the situation around your vehicle. If you miss vital information, you may act in a way that endangers everybody on the road.
Not all visual information is equally important. While searching the road, you must actively target risk-increasing situations such as:
- Nearby vehicles, pedestrians, animals or cyclists
- Objects, obstacles or debris in the roadway
- Anything which may block your line of sight along your intended path of travel
- Curves or hills, railroad crossings, upcoming intersections or interchanges
- Road signs which indicate a change in speed limit or another road law
Evaluating road hazards
As a defensive driver, you must be able to detect potential hazards 360 degrees around your vehicle. Furthermore, you must know what to look for, where to look, how long to look for and how to prioritize hazards in order of urgency, to decide which to act against first.
You will never be able to completely eradicate the risk posed by all roadway hazards simultaneously, as avoiding one hazard may increase the potential risk associated with another. Hazard evaluation and prioritization is important, as it enables you to identify the most prominent dangers and pick an action which decreases the overall risk of a situation as much as possible.
The scanning range
The riskier the driving environment, the further ahead on the roadway you must focus your visual search. In normal conditions, a driver should scan the roadway roughly 10 to 15 seconds ahead of their vehicle. This will be around a quarter-mile when traveling at highway speeds, or about one block when traveling at inner-city speeds. If you are driving in a high-risk situation or at especially fast speeds, you should increase your scanning range to 20 to 30 seconds ahead. This will allow you more time to perceive and evaluate danger.
Scanning the roadway as far ahead as possible is an extremely important visual search strategy. At a distance, you will be able to form a bigger picture of the environment in your target area and spot potential dangers in time to take appropriate action. For example, you may see the doors closing on a passenger bus around 15 seconds ahead. This tells you that by the time you reach that area, you may need to make allowances for the bus driver seeking to re-enter traffic.
Keeping your eyes moving
As there is so much information to absorb at various points between your vehicle and your target area ahead, not to mention to the sides and rear of the car, it is imperative that you keep your eyes moving between these areas as you scan the road. Otherwise, you may miss hazards and other important roadway changes while your gaze is fixed elsewhere. Remember to regularly check your rear-view mirror, side-view mirrors and blind spots, while scanning the road.
Keeping your eyes moving will also help to keep you actively engaged in the search process. Staring at a single point for too long can lead to “zoning out” whereby your mind wanders and you stop consciously registering any visual information.
Developing a comprehensive search pattern
Organizing your visual search by adopting a comprehensive search pattern is the key to absorbing as much information as possible. It is not enough simply to bounce your gaze mindlessly from one spot to another, as you are unlikely to distribute your attention equally between all parts of the roadway without a methodical approach.
You can organize your search pattern however you choose, though you must be sure to cover all areas and avoid fixating on a single spot for more than about a second – unless exceptional circumstances demand it. Your visual search pattern might look something like this:
The target area, 20 to 30 seconds ahead.
Secondary range, prior to the target area.
Nearby driveways and intersections.
The area behind your car with your rear-view mirror.
The immediate range, directly in front of your car.
Adjacent lanes using side-view mirrors.
Blind spots, by turning to look over your shoulder.
Immediate and secondary ranges again.
The rear-view mirror again.
Dashboard gauges to check speed and other vital information.
Remember that you should always drive with a mind to protect your view of the road. Keep an eye out for upcoming obstacles that may block your line of sight and be sure not to drive too closely behind large vehicles which may entirely obscure the roadway ahead. When these line of sight obstructions occur, alter your lane position to maximize your view.
Keeping your vehicle clean and well-maintained is another important search-enhancing strategy. Make sure your wiper fluid is topped up and the wipers themselves are in good working order. Keep your windshield clear of dirt and be sure to adjust your side-view and rear-view mirrors, prior to starting your journey.
Preparing to maneuver
A thorough visual search must be performed before any maneuver you intend to make. This may begin, but should not end, with checking the new area of the road you intend to drive over. You must then check all other areas of the roadway around and behind your vehicle, to make sure no other road user is following a path that will conflict with your maneuver.
It is impossible to perform even the simplest of maneuvers safely, without conducting a search of the road beforehand. Always check ahead, to your sides and to the rear of your vehicle every time you wish to:
- Change lanes
- Merge into a new lane of traffic
- Enter or exit a limited-access highway entry or exit ramp
- Enter an intersection
- Alter your speed significantly
- Pull onto a roadway from a driveway, alley, curb or shoulder
- Back up
Finding time for maneuvers
Never jump right into a maneuver without first ensuring you have enough time to begin, execute and finish the maneuver comfortably, without conflicting with other traffic. Here are some rough guidelines:
- You will need a four-second gap to change lanes
- It takes a seven-second gap to cross an intersection on a four-lane road
- You will need a nine-second gap on the right and a seven-second gap on the left to complete a left turn.
- It takes approximately eight seconds to merge
- You will need an eight-second gap in traffic moving from the left to complete a right turn
- It takes 20 to 30 seconds to complete a three-point turn
- Remember to wait two seconds before proceeding when a traffic light changes to green at an intersection, to make sure the way ahead of you is clear
Keep in mind that these rules are approximate. You may need slightly more or less time to complete any of these maneuvers, depending on how your vehicle handles, the speed at which you are traveling and road conditions. The best way to stay safe is to always allow yourself slightly more time than you think you need. That way, you should never have to endanger yourself by rushing a maneuver.
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