Chapter 7: Negotiating Intersections
Chapter 7: Negotiating Intersections
7.1 Searching Intersections
Collision Risk at Intersections:
Intersections have a higher chance of collision than any other point on a roadway.
They are dangerous due to crossing paths of many drivers and frequent unexpected stops.
More than (1/3) of all collisions and (1/4) of all fatal collisions occur at intersections.
A primary reason for collisions is a driver's failure to identify a safe path of travel.
Identifying Intersections Ahead:
Look for clues such as: street signs, street lights, roadway markings, crossing traffic, parked vehicles on cross streets, turning traffic, rows of fences and mailboxes, traffic stopping, and power lines.
Intersection Designs:
Most common: Two roadways crossing or a railroad crossing in a (+) or (X) pattern.
Y-intersections: One roadway divides into two, or two join to form one.
T-intersections: Formed when one road ends at another.
Traffic circles: Several roadways meet at a circle.
Searching Procedures at Intersections:
After identifying an intersection, determine if you have an open zone for your intended path.
Initial Search: Check left-front, front, and right-front zones for openness.
Line-of-Sight Restrictions: Look for anything preventing you from seeing if your path is safe.
These can be caused by the environment or other highway users.
When restricted, zone checks should become more frequent, primarily focusing on the front zone.
Wider Search: Once within (4-6) seconds of an intersection, widen your search to include more information from the right and left.
If the front zone is clear, continue moving.
If not clear, prepare to stop or change your path.
Specific Search for Restrictions: Look for a car stopped on the left, a parked vehicle on the right, or a double-parked delivery truck.
Head Turns: Turn your head (45) degrees to the right or left to see beyond line-of-sight restrictions.
Pausing Your Search: Briefly pause at each zone to detect objects; avoid a constant scan to prevent missing objects.
Continuing Moving Ahead:
You can proceed if the traffic light is green, or if there are no signals/signs, and the front, right-front, and left-front zones are open.
Frequent checks are needed, especially with line-of-sight restrictions.
Continue searching left-front, front, and right-front zones for path changes or restrictions.
Point of No Return:
This is the point beyond which you can no longer stop safely without entering the intersection.
Under normal conditions, it is approximately (2) seconds from the intersection.
Once past this point, continue through the intersection.
Adjusting Lane Position and Speed for Restrictions:
If a line-of-sight restriction exists, consider changing your lane position and reducing speed to gain more time to see.
If the restriction is on the right with an open left-front zone, move to lane position (2) (left side of your lane) and reduce speed.
If the restriction is on the left with an open right-front zone, move to lane position (3) (right side of your lane) and reduce speed.
If both left-front and right-front zones are closed, stay in lane position (1) (center) and further reduce speed.
Lane Changes: Lane changes are not allowed within an intersection. Select your best path before entering.
Deciding to Stop:
Stop if you identify or predict a closed zone or a line-of-sight restriction ahead.
Closed Front Zone: Indicated by a yellow or red traffic light, a STOP sign, or something moving into your path (less than (10) seconds availability).
Braking Procedure:
As soon as a closed zone is identified, check your rear zone.
If the rear zone is open, begin braking.
If the rear zone is closed, tap your brake pedal multiple times to alert the driver behind you that you are stopping.
Moving After a Stop:
Once stopped and the front zone is clear, search at (90)-degree angles to the right and left before moving.
Pause briefly at each target area for a clear view.
When turning, your final check should be in the direction of your intended path of travel.
If stopped behind another vehicle, wait (1) second after it starts moving to ensure room for response to sudden stops.
7.2 Controlled Intersections
Definition: An intersection where traffic signals or signs determine the right of way.
Always obey all signs and signals.
Yield the right of way to through traffic.
Control Signs:
STOP Sign: Requires a full stop at the stop sign, crosswalk, or stop line.
YIELD Sign: Requires slowing down and yielding the right of way to vehicles on the through street.
Blocked View at STOP Sign (Crossing Traffic Procedure):
Look around and search at a (45)-degree angle at location (1), continuing to search left, front, and right as you creep forward. Check your rear zone.
Check for pedestrians and prepare to make a legal stop before moving beyond location (2). Look for turning vehicles.
Stop with your front bumper even with the curb. Search (90) degrees to the left and right. Ideal searching when front bumper is even with the left side of parked cars (location (3)).
When an open front zone and a gap of at least (7) seconds (from left and right) are clear, accelerate to proper speed. Check the rear zone after clearing the intersection.
Joining Traffic - Right Turn Procedure:
At location (1), search front zones for pedestrians and turning vehicles. Check rear zone and stop.
Stop at location (2) with the front bumper even with the curb. Search (90) degrees left and right. Evaluate target path and zones. When clear (no line-of-sight restrictions and (7) second gap), begin turning. Turn head towards target, accelerate, and turn the steering wheel.
If line-of-sight is restricted to the left, creep forward slightly to improve view.
At location (3), turn no farther than (3-4) feet from the curb. Accelerate to traffic speed and check the rear zone.
Joining Traffic - Left Turn Procedure:
Before moving beyond location (1), position your vehicle in lane position (2). Search front zones for pedestrians and turning vehicles. Check rear zone and stop.
Stop with front bumper even with the curb. Evaluate zones. When clear (no line-of-sight restrictions and (7) second gap), begin turning. Move forward slightly until your body is even with the curbline. Check front zones, turn head towards target, accelerate, and turn the steering wheel.
At location (3), turn to end up in lane position (2). Accelerate to traffic speed and check the rear zone.
Traffic Signals:
Typically red, yellow, and green. May also include yellow or green arrows.
Approach signals with caution, especially when a light turns green.
IPDE Process for Signals:
Identify: Recognize the signal color immediately.
Predict: Anticipate the light changing as you approach.
Search (12-15) seconds ahead, evaluating the light color and cross-traffic.
Check front zones before the braking point; if the light will be red or cross-traffic closes the zone, prepare to stop.
Types of Green Lights:
Stale Green Light: Has been green for a long time. Be prepared to slow as it will likely turn yellow soon.
Fresh Green Light: Has just turned green. Does not guarantee a clear path; check for drivers running the red light on the cross street and ensure an open zone before proceeding.
Yellow Light:
Decision: Stop or proceed.
If it turns yellow before the point of no return, check the rear zone and stop if safe; otherwise, go through.
Be cautious making left turns on a yellow light; wait for all oncoming traffic to stop.
Red Light:
Must stop. Check your rear zone as you slow.
If a vehicle is ahead, stop where you can see its rear wheels touching the roadway.
If no vehicles behind, continue checking your rear zone often.
Delayed Green Light:
One side of the intersection has a green light while oncoming traffic remains red.
Allows traffic from one side to turn or go straight first.
Obey your signal only; do not assume you can proceed with oncoming traffic.
Unprotected Left Turns:
Made at a signal-controlled intersection without a specific left-turn light.
You must yield to oncoming traffic.
Protected Left Turns:
Made when a special left-turn light, green arrow, or delayed green light allows you to turn while oncoming traffic is stopped.
Left-Turn Light: Provides a protected turn, sometimes located over the turn lane without signs.
Green Arrow: Appears with normal signals. May simply turn off to indicate the end of the protected turn, or be followed by a yellow arrow warning. Watch for oncoming drivers misinterpreting your green arrow.
Turns on Red:
Permitted in all states and DC, though local governments may prohibit (watch for signs).
Right on Red:
Come to a full stop as at a STOP sign.
Move to a position with clear visibility.
Search front zones for openings.
Yield the right of way to any vehicle or pedestrian in or approaching the intersection.
Complete the turn into the nearest right lane.
Left on Red:
Most states allow from a one-way street onto another one-way street.
A few states allow from a left-turn lane on a two-way street onto a one-way street.
Follow the same procedure as right on red, but look for traffic in your front and right-front zones, then turn into the nearest left lane.
Controlled Railroad Crossings:
Feature red lights and crossing gates.
Stop completely when lights flash and/or gates are down.
Remain stopped until lights stop flashing and gates are raised.
Driving around gates is illegal, unsafe, and costly.
Proceed cautiously when clear.
7.3 Uncontrolled Intersections
Definition: Intersections without signs or signals to regulate traffic.
Typically found in low-traffic residential areas.
Can be dangerous as drivers may not expect cross traffic or pedestrians.
Assume an intersection is uncontrolled if no signs/signals are visible.
Always predict that other traffic will not stop.
Reduce speed, search aggressively, and be prepared to stop.
Uncontrolled Intersection Searching Procedures:
After identification, check your rear zone.
Determine if you have an open path of travel (left-front, front, right-front zones).
Continuously look for line-of-sight restrictions.
Ensure clear open space in all front zones before entering.
Search for zone changes that could close your path.
If a closed zone due to restriction is identified, check the rear zone again, remove foot from accelerator, and cover or apply the brake.
Yielding at Uncontrolled Intersections:
If vehicles approach from left and right, the driver on the left must yield to the driver on the right. However, predict the worst-case scenario and never assume the other driver will yield.
Treat as a YIELD sign: slow and be prepared to stop.
Traffic Circle: Yield to vehicles already in the circle (coming from your left). Be alert for vehicles entering from your right-front zone.
Pedestrians: Always yield to pedestrians, regardless of their actions (even if breaking traffic law).
IPDE Process at Specific Distances from Uncontrolled Intersections:
At (12-15) Seconds Out:
Check roadway conditions and closed zones (left-front, front, right-front).
Identify if the intersection is controlled.
Identify other roadway users.
Search (45) degrees to each side for line-of-sight restrictions. Solve problems before entering.
Locate your point of no return.
Check rearview mirror for following traffic and slow down. More restrictions mean more need for IPDE.
At (4-6) Seconds Out:
Recheck your immediate path of travel.
Search left-front and right-front again for an open zone.
If a vehicle is approaching from left or right, prepare to stop.
Recheck traffic to the rear.
At (2) Seconds Out (Point of No Return):
Briefly pause your search while evaluating zones for conflicts. This is your last chance to stop safely.
Brake to a stop if your front zone closes.
Search left and right again.
Proceed when your path is clear.
Uncontrolled Railroad Crossings:
Lack flashing red lights or crossing gates.
Always marked with a round, yellow railroad-crossing sign ( ext{approx.} 250 ext{ feet} in cities, ext{approx.} 750 ext{ feet} in rural areas).
A large white (X) -shaped crossbuck sign is located beside the crossing, often with a white (X) painted on the roadway.
Treat as an intersection with a YIELD sign: slow and be prepared to stop.
Trains warn of approach, but drivers are primarily responsible for avoiding collisions.
Train stopping distances are always longer than a car's.
Procedures at Uncontrolled Railroad Crossings:
Slow down. Check tracks both sides and rear traffic as you approach the sign.
Turn off radio, AC, or heater fan; open window if noisy to listen for trains.
Reduce speed for rough crossings or line-of-sight restrictions; note number of tracks.
If a train approaches, stop at a safe distance before the tracks.
Wait for the train to clear, then carefully check for another train on other tracks.
If safe, increase speed to at least (20 ext{ mph}) to ensure the vehicle clears the tracks even if the engine stalls.
For stickshift vehicles, shift to a lower gear before crossing to prevent stalling. Never shift while on tracks.
Drive onto tracks only when you have enough space and speed to clear them. Ensure vehicles ahead clear before you start. Never stop on railroad tracks.
When following buses or trucks hauling flammable contents, be prepared to stop, as many states require them to stop at tracks.
7.4 Determining Right of Way and Judging Gaps
Right of Way Definition:
The privilege of having immediate use of a certain part of a roadway.
You have the right of way only when other drivers give it to you; it cannot be taken.
Yielding the Right of Way:
Letting others go first to ensure safety.
Sometimes legally required, sometimes an act of courtesy.
Key Points in Yield Situations:
Your actions should not cause those to whom you yield to slow, stop, or change their path.
Traffic signs and signals indicate who should yield, but do not force traffic to stop for you.
Do not assume others will always yield to you.
It is often safer to yield even when the law suggests otherwise.
Failure to yield is a frequent cause of fatal collisions.
Situations When You Must Yield the Right of Way:
At STOP Signs:
To pedestrians in or near the crosswalk.
To all traffic on the through street.
At Fresh Green Lights:
To pedestrians still in the crosswalk.
To vehicles still in the intersection.
At YIELD Signs:
To all pedestrians in or near crosswalks.
To all vehicles on the cross street.
Two Stops from Alley, Driveway, or Private Roadway:
First stop: To pedestrians before reaching the sidewalk.
Second stop: To all vehicles on the street.
To Emergency Vehicles:
When sounding a siren or using a flashing light (stop clear of the intersection close to the curb and wait for the vehicle to pass).
When Turning Left at Any Intersection:
To all pedestrians in your turn path.
To all oncoming vehicles that are at all close.
At Four-Way Stops:
To all pedestrians in or near crosswalks.
To vehicles that arrive first.
To a vehicle from the right if you both arrive at the same time.
At Uncontrolled Intersections:
To pedestrians in or near the crosswalk.
To any vehicle that has entered the intersection.
To a vehicle from the right if you both arrive at the same time.
Crossing and Joining Traffic:
Joining Traffic: Turning right or left into lanes of other vehicles.
Judging the Size of a Gap:
Gap Definition: The distance between vehicles.
You must judge the size of gaps to enter/pass through intersecting traffic safely.
Required gap size varies by maneuver and traffic speed.
Time Estimates for Maneuvers from a Stop:
Crossing an intersection: (4-5) seconds.
Turning right and accelerating to (30 ext{ mph}): ext{approx.} (6) seconds.
Turning left and accelerating to (30 ext{ mph}): ext{approx.} (7) seconds.
Gap Size Examples:
If through-street traffic is traveling (30 ext{ mph}), you need a gap of about two-thirds of a block in each direction.
A right turn requires about (6) seconds to reach through-street speed without interfering with traffic flow.
A left turn is more dangerous as you cross paths from the left before entering traffic from the right.
The gap needed for a left turn is greater than for a right turn.
At (55 ext{ mph}), a left turn needs a gap of more than (3.5) blocks.