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Driver Attitudes and Behaviors at Intersections and Potential Effectiveness of Engineering Countermeasures

Publication Number: FHWA-HRT-05-078
Date: November 2005

Driver Attitudes and Behaviors at Intersections and Potential Effectiveness of Engineering Countermeasures

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APPENDIX D. TABULAR SUMMARY OF THE FOCUS GROUP RESULTS

RESULTS TABLES TERMINOLOGY

For each scenario and countermeasure, the participants discuss a set of questions or themes. Key discussion points and opinions for each of these questions or themes are presented in table format after the text. Tables are organized into three columns containing information about:

Group: The first column lists the set of respondents (based on age group or geographic location) that predominately held the opinion expressed.
Opinion: The middle column summarizes the opinion or response.
Strength: The last column presents an approximation of the proportion of respondents from the indicated group (first column) that shared the opinion.

Group identification

The group column uses the following terms individually or in combination to indicate which set of participants held a particular opinion.

Older	Respondents in the older groups from all locations
Middle-aged	Respondents in the middle-aged groups from all locations
Young females	Respondents in the young female groups from all locations
Young males	Respondents in the young male groups from all locations
All	The opinion was generally held by all groups and no sub-set of groups stood out in terms of the number of participants sharing that opinion
Younger	Respondents in both the young male and young female groups from all locations
City name	Respondents from all groups at the indicated focus group location (Washington, DC, Chicago, or Seattle)

Strength Quantification

The strength of opinion was described using the following ordinal scale:

One < Few < Some < About Half < Many < Most < Almost All

These measurements should be taken as a general approximation, and in many cases are based on the focus group moderator’s impression of how many focus group participants shared a particular opinion. Where possible, the video recordings were used to generally confirm these magnitudes.

In some instances, more specific measurements are indicated (e.g., 1/3, 1/5, etc.). These measurements are based on more direct measurements, such as hand counting, or by specifically asking each participant.

In a few instances in which the same opinion was shared by different proportions of individuals from each group, the following syntax is used in the Group and Strength columns:

Table 12. Syntax for Group and Strength columns.

Group	Opinion	Strength
Group1 / Group2		Magnitude 1 / Magnitude 2

In this case, which group goes with which magnitude is indicated by the order of the terms relative to the "/" marks. In the example above, Group 1 goes with Magnitude 1, and Group 2 goes with Magnitude 2.

Scenario 1: Red–Light Running

Approaching a signalized intersection at speed, the light turns yellow. The driver is far enough away from the intersection that he/she can stop if he/she brakes hard, but is likely to enter the intersection on an early red if he/she accelerates.

Table 13. What are drivers most likely to do in this situation (scenario 1)?

Group	External Factor	Strength
Older	Stop at the intersection.	Almost all
Middle-aged	Go through.	About half
Young female	Go through.	About half
Young male	Go through.	Three-quarters
Young male	Go through, even if the light just turned red instead of yellow.	Some

Table 14. What factors influence driver decisions to stop (scenario 1)?

Group	Factors That Incline Drivers To Stop	Strength
Older	Stopping is their default strategy.	Most
Older	They make an automatic assumption that the lead vehicle will stop (even if this is unlikely).	Most
Older	The longer the light is yellow, the more inclined they are to stop.	Some
Middle-aged	The possibility of crashing into the lead vehicle if it decides to stop suddenly.	Many
Middle-aged	If they think that there could be red-light cameras or police in the area.	Some
Young female	Often use predetermined criteria based on several factors including roadway type (urban/rural), traffic volume, and pedestrian density.	Many
Young female	If lead vehicle looks like it will stop or turn right.	Many
Young male	If the lead vehicle looks like it will stop or turn at the last minute.	Many
Young male	Getting a ticket.	Many
Young male	Having to speed up too much to get through.	Some
Young male	Rush-hour synchronized traffic signals because they would just have to wait at the next light if they went through the current one.	Some

Table 15. What factors influence driver decisions to go through (scenario 1)?

Group	Factors That Incline Drivers To Go Through	Strength
Older	The risk of getting stuck encroaching into the intersection if they cannot stop in time.	Some
Older	Not wanting to get rear-ended if they did stop.	Many
Middle-aged	Going through is the default strategy, unless they think that they do not have enough time to get through.	Some
Young female	Often used predetermined criteria based on several factors including roadway type (urban/rural), traffic volume, and pedestrian density.	Many
Young female	Being in a rush.	Many
Young female	Sparse traffic/off hours (evening/early morning).	Some
Young female	Frustration at traffic volume.	Some
Young female	If the vehicle behind them is following too closely.	Some
Young male	If the lead vehicle is going through.	Many
Young male	If they would otherwise have to slam on their brakes to stop.	Many
Young male	Being in a rush.	Many
Young male	Rush-hour synchronized traffic signals because if they miss the current light it will make them miss the timing for the next several lights.	Some

Table 16. What are some additional external factors that influence driver decisions (scenario 1)?

Group	External Factor	Strength
Middle-aged and younger	Having passengers in their car, especially children.	Many
All	Type of person driving the car in front or behind them (specifically, whether they appear likely to go or stop on a yellow light).	Some
All	Age, type, and/or cost of vehicle in front.	Some
All	Transporting a dog (that is not restrained).	Some

Table 17. Do drivers anticipate and plan a response for a dilemma-zone situation as they approach an intersection, or do they react on the fly to the yellow light and the corresponding driving conditions (scenario 1)?

Group	Response	Strength
Older	Likely to plan ahead and anticipate a response.	Most
Middle-aged	Likely to rely on "gut" or instant decision without any prompting.	Most
Younger	Likely to plan ahead and anticipate a response.	Many
Younger	Likely to rely on "gut" or instant decision without any prompting.	Some

Table 18. What other information do drivers use when making decisions regarding going through or stopping (scenario 1)?

Group	Other Information	Strength
All	Pedestrian signal status to anticipate the light change.	Some
Middle-aged and younger	Familiarity with intersection, specifically if they know it is a long light or has a long yellow phase.	Many
Older	Lane markings (if they become solid).	One

Table 19. Is going through the light ever a deliberate act (scenario 1)?

Group	Frequency and Reason Why	Strength
Young males	Sometimes, just to "try to make it" or based on mood (aggressive, frustrated, or rushed).	About half
Young females	Sometimes, just to "try to make it" or based on mood (aggressive, frustrated, or rushed).	About a quarter
Older	Sometimes, just to "try to make it" or based on mood (aggressive, frustrated, or rushed).	Few
Middle-aged and younger	Sometimes, to avoid slamming on the brakes or being rear-ended.	Many

Table 20. Is it ever the case that drivers do not notice the signal until it is too late to do anything but continue through the red? Do drivers ever try to stop in this case (scenario 1)?

Group	Frequency and Reason Why	Strength
Young males	Rarely—but if distracted, they just go through.	Some
Other than young males	Rarely—decision to go is based on their assessment of how safe it is to stop.	Some

Table 21. Complicating factors (scenario 1).

Group	Factor	Strength
Other Vehicles
All	They are concerned about oncoming vehicles turning left across their path.	About a quarter
Other than young males	They are concerned about cross traffic ready to enter the intersection at speed as soon as their light turns green.	Many
Congestion
All	Heavy congestion is a reason for not running lights.	Many
All	Long delays are a reason for running the light.	Many
Weather
Chicago	Ice and snow are a reason for caution but also for running the light if it means avoiding skidding or losing control.	Some
Seattle	Slick oil with rain is a reason for caution but also for running the light if it means avoiding skidding or losing control.	Some
Poor Visibility
Older/middle-aged	Poor visibility at night and in bad weather leads drivers to be more cautious and slow down.	Many/Some
All	Vision obstructions from trees, buildings, etc., make drivers more cautious.	Many
Glare
Older	Glare from certain types of lights (e.g., halogen) is problematic.	Some
Seattle, WA, younger	Glare from sun during the day can be problematic.	Some
Poor Traction
All	Poor traction makes drivers more likely to go through the intersection rather than risk skidding or losing control of their vehicle.	Many
Terrain
Seattle	Hills can obstruct their view.	Some
Seattle	Hills would prompt those driving a stick-shift to go through a light to avoid having to stop uphill.	Some
Other Factors
All	The presence of pedestrians would prompt caution, especially at night when they are harder to see.	Many
Middle-aged and younger	The presence of red-light cameras or police would prompt drivers to be more cautious.	Some
	Proximity to school zones leads drivers to use "extreme caution" at intersections.	Some
All	Their vehicle type and that of the lead driver has different effects based on the vehicle’s ease of stopping (e.g., less with SUV), how much it obstructs vision, and how new or expensive it is.	Some

Table 22. What are driver attitudes regarding red-light running (scenario 1)?

Group	Attitude	Strength
All	Those involved in intersection crashes or near-misses view red-light running as being much more dangerous than other drivers did.	Some
Older	It is a serious problem and something that too many people do without regard for the consequences.	Most
Middle-aged	Although they typically run yellow lights and sometimes red lights, they do not view their actions as contributing to the problem of true red-light running—that is something others do.	Many
Younger	It is more of a monetary than safety issue, with their primary concern to avoid traffic tickets.	Most
Younger	Avoiding getting a ticket is like a game, which prompts them to avoid intersections where they are more likely to get a ticket.	Many

Table 23. What do drivers believe are the consequences of running red lights (scenario 1)?

Group	Consequence	Strength
All	Tickets and expensive fines.	About half
All	Getting into a crash and causing injuries to pedestrians, passengers, themselves, or other drivers.	About half
Middle-aged and young females	Injuries to passengers.	Some
Older	Injuries to themselves.	Some
All	Being "at fault" and liable for any crashes.	Some

Table 24. Do drivers’ beliefs about the consequences come into play in their decision process (scenario 1)?

Group	Impacts of Consequences	Strength
All	The potential for crashes, hitting pedestrians or getting hit by other drivers makes drivers more cautious and causes them to alter their driving.	Many
Older	They are not influenced by the possibility of getting a ticket.	Most
Middle-aged and younger	The presence of cameras and police would cause them to slow down and be more careful.	Many
Young males and females	Getting a ticket had previously produced only a transient improvement of their safety behaviors, and they often adapt by avoiding intersections where they think they might get a ticket while continuing to run red lights at other intersections.	Most
Younger	They view red-light tickets as simply the cost of driving and would not try to change their behavior.	Few
All	The possibility of hitting pedestrians and especially children causes them to be more cautious and slow down.	Many
Middle-aged and young females	The are most concerned about the impact of their actions on the safety of their passengers, especially young children.
Older	Concerns about being "at fault" in a potential crash causes them to drive more safely.	Some

Table 25. How does experience with critical events (e.g., crashes, near-misses) impact their decisions, attitudes, beliefs, etc. (scenario 1)?

Group	Impacts of Experience	Strength
All	Impacts were strong but very situation-specific, with increased caution not generalizing to other situations.	Many
All	Serious crashes involving family or friends cause them to be more cautious in similar situations.	Some
Older	They are less likely to see themselves as being "at fault," which makes them less likely to change their behavior.	Some

Table 26. To what extent is red-light running behavior impacted by perceived social norms (scenario 1)?

Group	Impacts of Social Norms	Strength
Older and middle-aged	They are neither concerned about nor influenced by social norms.	Most
Younger	They could be influenced by peers to run a red light.	Few
Younger	They become more cautious and less likely to go through the light if they are driving with their parents.	Many
Middle-aged women	They become more cautious with their older children in the car because they want to serve as a good role model.	Few

Table 27. To what extent is the act of going through the light under their control (scenario 1)?

Group	Aspects of Perceived Control	Strength
All	Going through the light is not under their control.	Many
All	What they perceive to be deliberately short yellow-phase durations makes it beyond their control.	Many
Older	Other vehicles coming up behind them too quickly make it beyond their control.	Many
Chicago, IL, and Seattle, WA	Slippery roadway conditions make it beyond their control.	About half
Younger	They are the most likely to take responsibility for their red-light-running behavior.	Some

Table 28. To what degree, if any, does habit (e.g., "I don’t think about it, I just always do it that way") affect whether or not drivers run a red light (scenario 1)?

Group	Impact of Habit	Strength
All	Going through a red light is viewed as something not done simply out of habit.	Almost all

Scenario 2: Left Turns at Busy Intersections

Stopped in the middle of an intersection, waiting to make a left turn on a busy street; an oncoming car is also waiting to turn left and makes it difficult to see other vehicles approaching in the next lane. There is no dedicated turning lane and no dedicated turn signal; cars are waiting behind to also turn left (or go straight).

Table 29. What are drivers most likely to do in this situation (scenario 2)?

Group	Action	Strength
All	Wait for the light to change to yellow or red to get some protection from oncoming traffic.	About half
Older and middle-aged	Avoid the left turn altogether by going straight, turning right, or planning a different route.	About half
Young females	Avoid the left turn altogether by going straight, turning right, or planning a different route.	Some
Young males/ females	Barge their way into the oncoming lane and force oncoming vehicles to slow.	About 1/4 / Few
All	Wait for the oncoming vehicle to turn, then go if there is no other oncoming traffic.

Table 30. What steps do drivers take in making the turns (scenario 2)?

Group	Action	Strength
Intersection Entry
All	Advance directly to the middle of the intersection without hesitation, regardless of how much traffic is coming.	Most
All	Wait at the stop line until there’s no traffic coming, then inch forward.	Few
Vehicle Positioning Within the Intersection
Older, middleaged, and young females	If they were going to turn, they would inch forward but stay straight in their lane.	Most
Young males	Position themselves in the lane of opposing traffic or slanted toward opposing traffic (yet protected by the oncoming turning vehicle).	Most
Young females and middle- aged	Position themselves in the lane of opposing traffic or slanted toward opposing traffic (yet protected by the oncoming turning vehicle).	About a quarter
Decision to Turn
All	They prefer to wait until no traffic is coming and there are no cars in sight.	Most
All	Look for an acceptable gap in oncoming traffic.	About half
All	Wait until the light changes yellow or red.	About half
Acceleration
All	Check for pedestrians before initiating the turn.	Almost all
All	Accelerate quickly to get out of the intersection as soon as possible.	Almost all
All	They feel uncomfortable when they go because they are concerned that they missed something or misjudged the gap.	Many

Table 31. How do drivers decide (what steps are involved) whether or not a gap in traffic is sufficient (scenario 2)?

Group	Response	Strength
How Decision Is Made
All	It depends on the speed and distance of oncoming traffic.	Most
All	They watch oncoming cars go by and try to gauge the time it takes to close the distance between themselves and the oncoming cars.	Some
All	They judge the gaps until they feel comfortable with enough distance to make a move.	Some
All	It is a "gut" decision.	Some
Factors That Directly Affect Gap Judgment
All	Familiarity with the intersection increases the likelihood that they will accept a smaller gap.	Some
Older/young males	The presence of passengers makes them more cautious and more willing to wait longer for a safe gap.	Many/ Some

Table 32. What other information or considerations come into play (scenario 2)?

Group	Action	Strength
All	They take advantage of the oncoming vehicle making its left turn to get a better view of oncoming traffic.	Most
All	They watch out for oncoming vehicles potentially going straight through from behind the oncoming turning vehicle, even when light is yellow or red.	Some
All	They look for turn signals in oncoming traffic behind the oncoming turning vehicle to make sure there will be no conflict when they try to turn—however, they do not always trust the signal.	Some

Table 33. What are some of the strategies that drivers use in this situation (scenario 2)?

Group	Action	Strength
All	They try to make eye contact with oncoming drivers.	Some
All	They look through the windows of the cars to see if they can get a better view.	Some
All	They make sure they are out far enough into the intersection so the other cars will see them and have to let them go when the light turns yellow or red.	Some
All	They get passengers to "spot" for them.	Some

Table 34. Complicating factors (scenario 2).

Group	Factor	Strength
Other Vehicles
All	They do not care about the cars behind them; however, about half still have strategies for addressing following vehicles in one way or another.	About half
All	They ignore following vehicles that start honking.	About half
Older/young females	They are concerned about following vehicles and go out of their way to accommodate them (e.g., by moving up far enough so that following vehicles can pull out and go straight).	Many
All	Oncoming vehicles behind the turning vehicle are a source of concern and lead to extra caution in case they try to get through the intersection in conflict with the driver’s vehicle.	Many
Congestion
All	Congestion prompts drivers to go through the light to avoid waiting through another light cycle.	Some
Pedestrians and Bicyclists
All	They always check crosswalks.	Many
Older	They also watch for skateboarders, roller bladers, and scooters.	Some
Older and middle-aged	They are concerned about pedestrians and bicyclists not following the rules, and being difficult to see at night.	Few
Night Driving
All	Reduced visibility causes them to be more cautious and willing to wait longer to be sure that it is safe to go through the light.	Many
All	They are more careful because of the increased number of drunk drivers on the road during this time.	Some
All	Night driving also has benefits because oncoming vehicle headlamps can be seen from farther away.	Some
Glare
Older	Glare from oncoming lights at night makes them more cautious.	Some
Younger	Glare from oncoming lights reduces their ability to judge the speed of the oncoming traffic, sometimes making vehicles appear closer or further away than they actually are.	Some
All	Having the sun in their eyes causes them to be more conservative in their gap judgments.	Some
Terrain
Seattle	Being on a hill would prompt them to wait for the light to turn red because they are less visible to oncoming traffic.	Some
Low—Traction Conditions
All	They are more cautious in the rain, ice, and snow because oncoming traffic would have a harder time stopping.	Many
Young males in Washington, DC	They do not think that weather is a factor unless it impacts visibility.	Most
Vehicle Type
All	Turning in this scenario depends on the type vehicle that both you and the oncoming driver are driving.	Many
All	Drivers of small cars have greater difficulty seeing the roadway (especially if the oncoming vehicle is a large SUV) and therefore have to be more cautious.	Some
All	Driving powerful cars with quick acceleration would make them more likely to accept smaller gap sizes.	Some
All	Drivers of large vehicles find this situation easier to deal with because they have a better view of the roadway.	Some

Scenario 3: Turning Left onto a Major Road with Moderate Traffic

A vehicle is stopped on a minor road with a stop sign, waiting to turn left onto a major road (that has no stop sign); a consistent flow of vehicles going at high speeds is crossing in both directions on the major road.

Table 35. What are drivers most likely to do in this situation (scenario 3)?

Group	Action	Strength
All	Make the turn.	More than half
All, especially older and young females	Abandon the left turn and make a right turn instead, followed by the necessary adjustments to get back on course.	Less than half

Table 36. What steps do drivers take in completing the action (scenario 3)?

Group	Action	Strength
Viewing Traffic
All	They check for pedestrians and creep forward slightly to get a better view.	Almost all
All	They do not go any further than the crosswalk until they had a chance to assess the situation and get a sense of the speed and timing of the traffic.	Many
Gap Judgment
All	They alternate between looking in both directions, starting with the right-going direction.	Most
All	They look at right-going traffic exclusively until there is a safe gap then look towards left-going traffic.	Few
Strategies for Turning
All	If there is a gap on the left but none on the right, they pull out after the first right-going car goes by and wait in the inside right-going lane until there is a sufficient gap in left-going traffic.	Almost half
All	They pull out into the outside right-going lane so that other cars would have to let them in.	Some
All	They wait until there are sufficient gaps in both directions.	Almost half
All	They wait (or hope) for a nearby traffic light to stop traffic in either direction so that they could have a larger gap.	Some
Making the Turn
All	They go into the outside left-going lane to avoid the car in the inside left-going lane coming up behind them too quickly.	About half
All	They wait until they are certain that they could at least get in "clear" past the inside left-going vehicle.	About half
All	They go into the inside left-going lane and then quickly signal and get over into the outside lane.	Some
All	They accelerate as quickly as possible to get up to speed with the car in the inside left-going lane.	Some

Table 37. What is the decisionmaking process (scenario 3)?

Group	Action	Strength
Information-Gathering Strategies
All	They alternately look back and forth and judge gaps in both directions, starting with vehicles in the right-going outside lane then the left-going inside lane, spending about equal time on each direction.	Most
All	They look exclusively at right-going traffic until there is a safe gap, and then look at left-going traffic for a safe gap, and also double-check the gap in right-going traffic before going.	Some
All	They split up the task by going into the middle of the roadway as an interim step, which allows them to focus on only one direction at a time.	Some
All	They focus on the car in the inside left–going lane, once they determine that the gaps in both directions are sufficient.	Most
All	They also focus on the car in the outside left–going lane, either because they want to get out of the way of the left-going inside vehicle or to turn directly into that lane.	Some
Decisionmaking
All, but especially young males	They make a "gut" decision to turn, based on experience and by factoring in speed and distance conditions, in addition to their car’s ability to accelerate.	Some
All	They become less patient as time passes and are more likely to make rash decisions.	Some
All, but especially young males	They think through the decision to turn and are very cautious, factoring in speed and distance conditions, in addition to their car’s ability to accelerate.	Some
All	They assume that other vehicles will slow down to avoid conflicts, but they also often looked for confirmation of that assumption before acting.	Some
All	They are concerned that crossing traffic might change lanes.	Few

Table 38. How do drivers decide (what steps are involved) whether or not a gap in traffic is sufficient? What factors are relevant (e.g., speeds, distance to cross, weather) (scenario 3)?

Group	Factor	Strength
All	They identify a safe gap based on speed and distance.	Many
All	They instinctively know how fast cars typically go, and based on that, they wait for a gap that they feel they can make it into.	Many
Middle–aged	They look beyond the nearest vehicles for safe gaps farther down the road.	One
All	They look for larger gaps in left–going traffic because it takes them longer to get there.	Some
All	Visibility factors, nighttime, glare, and hills affect gap judgments.	Many
All	Being impatient makes them more likely to make bad judgments about acceptable gap size and the distance of approaching cars.	About 1/5

Table 39. What size gaps are drivers comfortable with (scenario 3)?

Group	Size	Strength
All	No vehicles in sight.	Few
All	One–car length.	Few
All	Somewhere between one-car length and no vehicles in sight.	Most
Young males	They are generally willing to accept smaller gaps than other drivers.	Many

Table 40. What external factors make the task of deciding when to turn more complicated/difficult or more demanding (scenario 3)?

Group	Factors	Strength
All	The presence of additional lanes in each direction because drivers have to watch for cars changing lanes.	Many
All	Obstructions along the curb make it harder to see (e.g., parked cars or vans, buses, buildings, shrubbery), and sometimes force them to inch out further than they are comfortable with.	Many

Table 41. Complicating factors (scenario 3).

Group	Factor	Strength
Other Vehicles
All	The presence of other drivers behind them is not a significant factor in this scenario.	Many
Congestion
All	They are willing to wait a relatively long time for a safe gap.	Many
All	The longer they wait, and the more impatient they become, the more likely they are to make bad judgments about the acceptable size of gaps and the distance of approaching cars.	About 1/5
Pedestrians and Bicyclists
All	They are more concerned about pedestrians and bicyclists in the crosswalk that they would be turning into than the one right in front of them because drivers feel that it is easy to see them there.	Most
Night Driving
All	They have mixed views about the impacts of nighttime because, while it makes it harder to judge the gap, it is also easier to see oncoming cars from far away.	Most
All	They feel that twilight is the worst time because other cars are hard to see and they do not often put on their lights.	Many
Glare
All	They will wait longer due to headlight glare in the country but not in the city, where glare is not as bad.	Many
All	If glare from the sun is bad they might not make the turn at all.	Some
Low-Traction Conditions
All	They are concerned about slippery conditions, including whether oncoming traffic will be able to stop or slow down.	Many
All	They are concerned about having problems accelerating, skidding, or "fishtailing" if they make the turn too quickly.	Some

Scenario 4: Rear-End Crashes

Approaching an intersection at speed, the car in front stops suddenly when the light changes to yellow; the driver needs to slam on the brakes to avoid a rear-end collision.

Table 42. How many drivers have been involved as the following vehicle in a rear-end crash or had a near-miss at an intersection (scenario 4)?

Group	Number	Strength
All	They have been involved in crashes or near-misses as both the lead vehicle and the following vehicle.	More than 1/6
All	They have been involved in a near-miss as either the lead vehicle or the following vehicle.	More than 1/3

It should be noted that although drivers responded with the frequencies presented above when directly asked about their involvement in rear-end crashes/near-misses, a far greater proportion of participants discussed these issues as if they had also encountered these situations.

Table 43. What were the circumstances that caused the incident to happen (scenario 4)?

Group	Circumstance	Strength
Not Paying Attention
All	They admit to not paying close enough attention to the road or car ahead.	Some
Younger	They have had near-misses or collisions as a result of using a cell phone or playing with the radio.	Many
Tailgating
All	They experienced crashes or near-misses when driving too close to the car in front of them.	Some
Making Faulty Assumptions About the Traffic Flow
All	They have gotten into rear-end collisions as a result of incorrect assumptions made about the traffic flow, such as that a lead vehicle will go through the intersection when it stops instead or by getting cut off by other vehicles.	Some
Going Too Fast
All	They have had rear-end collisions because they did not slow down soon enough after a lead vehicle slowed abruptly.	Some
Middle-aged and younger	They have had rear-end collisions because they were late and did not sufficiently slow down as they approached the intersection.	Some

Table 44. How closely do respondents typically follow other vehicles? What factors determine how closely drivers follow other vehicles (scenario 4)?

Group	Response	Strength
How Closely They Follow
All	Their chosen following distance is based on rules of thumb, such as the 2-second rule or other heuristics.	Many
Older and young females	They generally leave "ample" room between themselves and the lead vehicle.	Many
Deciding Factors
All	The distance at which they follow other vehicles depends on the types of vehicles that they and others are driving.	Some
All	They leave more space when driving an SUV or other vehicle that stops more slowly.	Some
Young males	They leave more space when driving a new car.	Few
All	The fact that they will be liable if they rear-end the lead vehicle prompts them to leave more space.	Many

Table 45. What are some strategies for avoiding rear-end conflict situations (scenario 4)?

Group	Action	Strength
As Following Vehicle
All	They hit their brakes as soon as they see any break lights go on in front of them.	Most
All	They look to see if there are other reasons why the lead car is slowing or stopping (such as the presence of pedestrians or a hazard on the road).	Few
All	They try to anticipate the situation using a variety of different methods.	Many
All	They leave more stopping distance in the front of them.	Some
All, but especially older	They slow down as they approach the intersection.	Some
As Lead Vehicle
All	They look in the rearview mirror at the following car more frequently.	Most
All	They pump their brakes ahead of time to warn other drivers that they will be stopping soon.	Some

Table 46. How do drivers detect or anticipate when the lead vehicle will slow or stop (scenario 4)?

Group	Action	Strength
All	They prepare to stop when the light changes and start watching the lead vehicle to see whether it will slow down or speed up to get through the light.	Most
All	They detect that the car in front of them is stopping because the brake lights capture their attention.	Almost all
Younger	They sometimes delay their decision to stop (although they will slow down) until they determine whether or not the lead vehicle is going through the intersection.	Many
All	They use various strategies to anticipate the light change and become more alert or prepare to stop before it does.	Some

Table 47. What are drivers likely to do in response to this situation (scenario 4)?

Group	Action	Strength
All	They would get into the inside or another lane if possible.	Many
All	They would go up onto the curb or shoulder if they could not stop on time.	Many
All	They would already be slowing down as they approached the intersection and would likely be able to stop in time.	Some
All	They would look behind them to see if they might get rearended if they stop too suddenly.	About a quarter

Table 48. Complicating factors (scenario 4).

Group	Factor	Strength
Lead Vehicle
All	They try to gauge how the driver in front of them drives as they go along and try to anticipate how they might behave based on the driver’s age and vehicle type.	Some
Younger	They leave more room if the lead driver appears likely to stop.	Some
All	They assume that heavier vehicles are likely to go through the light.	Few
Congestion
All	Congestion makes them tailgate more closely during rush hour.	Some
Poor Visibility
All	They do not think that this is a factor because the situation requires attention to their immediate surroundings, which would not be affected by poor visibility.	Some
Glare
All	They leave more space in front of them if glare from the sun makes it hard to see.	Few
Low-Traction Conditions
All	Slippery conditions are not a big factor because they do not think that they have any choice but to try to stop suddenly in this scenario.	Some
All	They leave more space between themselves and the car in front of them when it was raining.	Few
Terrain
All	They anticipate that it is more difficult to stop while going downhill and start breaking sooner.	Some

COUNTERMEASURES

The following issues were addressed for each countermeasure:

Would implementing this countermeasure improve safety?
What are some of the implementation issues?
What are the advantages and disadvantages of the countermeasure?

Countermeasure 1.1: Red-Light Camera

Table 49. Would implementing this countermeasure improve safety (countermeasure 1.1)?

Group	Opinion	Strength
Washington, DC, and Chicago, IL, older	They are strongly opposed to red-light cameras and do not feel that they improve safety.	Almost all
Seattle, WA, older	They think that it is a great safety improvement.	Almost all
Washington, DC, and Chicago, IL, young males	They think that red-light cameras work and improve safety, based on their direct experience with them or from what they hear or read about them.	Almost all
Seattle, WA, young males	They are more reluctant to admit that they would improve safety and they did not trust them.	Most
Middle-aged and young females	They are in favor of the cameras and feel that they help create safer situations since they had changed their own behavior in response to the cameras.	About half

Table 50. What are some of the implementation issues (countermeasure 1.1)?

Group	Issue	Strength
All	For cameras to be effective, drivers would need to be educated about them by either posting signs where they are located or through public service announcement campaigns.	Many
All	Cameras should only be placed at dangerous intersections or places where many people run red lights.	Some
All	Cameras would be ineffective with habitual red-light runners or drunk drivers because these drivers blatantly disregard the law and would probably disregard the cameras as well.	Many
All	They have mixed views on the effectiveness of periodically changing the camera locations.	Many
All	Cameras might be susceptible to vandalism if they are positioned within reach of the ground.	Few

Table 51. What are some of the advantages and disadvantages (countermeasure 1.1)?

Group	Issue	Strength
Advantages
All	Safety is the primary advantage noted.	Many
All	Cameras would free up police officers for other activities.	Some
Disadvantages
All	They do not trust cameras to work properly or as described (that they only take a picture of a driver entering the intersection after the light has turned red).	Most
All	Drivers believe that the yellow-phase duration is timed for maximizing revenue, not safety or traffic flow.	Many
All	Cameras give the impression that "big brother" is watching you.	Many
All	If they are wrongly accused, they would be unable to contest it because the photo provides indisputable evidence.	Some
Older	Younger respondents would benefit and learn more from the effect of being pulled over by actual police officers versus just getting a ticket in the mail.	Many
All	Cameras could cause more rear-end collisions because people might slam on their brakes if they saw a camera or a flash.	Many
All	Cameras could slow traffic flow.	Some
All	There is a possibility of wrongfully getting a ticket if someone else is driving your car.	Some

Table 52. What would it take to make red-light cameras acceptable (countermeasure 1.1)?

Group	Issue	Strength
All	Fairness is critical—those turning left in the middle of intersections when the light turns red and those making right turns on a red should not get tickets.	Many
All	Cameras are fine if their goal is to improve safety, but not to raise money, which is what they believe is currently the primary purpose of cameras.	Some
All	A "three strikes, and you’re out program" for drivers that are unfamiliar with the cameras.	Some
All	It would be helpful if the camera picture could identify the driver so that the vehicle owners could determine if the ticket was the result of someone else driving their vehicle.	Some
All	There should be a way to contest the ticket because of extenuating circumstances (e.g., slippery roads), which are not adequately captured in the camera picture.	Few
All	Cameras would be more acceptable in high-priority locations such as intersections near schools.	Few

Countermeasure 1.2: High-Visibility Traffic Lights

Table 53. Would implementing this countermeasure improve safety (countermeasure 1.2)?

Group	Opinion	Strength
Older	It would be a welcome help to these drivers in addition to being effective for improving safety in general.	Most
Young males	It would not help since lack of conspicuity was not the reason they go through red lights.	Most
Middle-aged and young females	It might be helpful.	About half
Middle-aged and young females	It would not apply to them.	About half

Table 54. What are some of the implementation issues (countermeasure 1.2)?

Group	Issue	Strength
All	This would work best in suburban or rural areas because it might otherwise get lost in all of the other downtown lights.	Many
All	It might help in the midst of the other downtown lights.	Few
All	This would be good at high-crash intersections, but not at all intersections.	Some
All	This might not be useful when the light was blocked by an SUV or a big truck; increasing the overall number of traffic lights (e.g., in different positions) might be more effective.	Some
All	There is some concern about the visibility of the yellow light next to the bright yellow background.	Some

Table 55. What are some of the advantages and disadvantages (countermeasure 1.2)?

Group	Issue	Strength
Advantages
All	Safety is the primary advantage noted.	Many
Disadvantages
Middle-aged and young males	The double red might be confusing and seemed expensive.	Some

Countermeasure 1.3: Advance Traffic Light Warning Signs

Table 56. Would implementing this countermeasure improve safety (countermeasure 1.3)?

Group	Opinion	Strength
Middle-aged and younger	It would be effective overall.	About 1/3
Older	It would be helpful and improve safety in most situations, especially in high-speed areas.	Almost all
Middle-aged and younger	It would not be effective because of lack of trust in the accuracy of the warning’s timing.	Some

Table 57. What are some of the implementation issues (countermeasure 1.3)?

Group	Issue	Strength
Middle-aged and younger	Drivers do not trust the sign to accurately take into account their actual travel speeds.	Some
Middle-aged and younger	Drivers might not see it or might confuse it with other signage (e.g., construction signs).	Some
Middle-aged and younger	Drivers might ignore the sign once they get used to it.	Some
All	It would be more effective in rural and suburban areas or on roads where the speed limit is above 56 km/h (35 mi/h).	Almost all
All	It would be helpful in areas of low visibility, on curves and hills, and in fog or other bad weather.	Some

Table 58. Advantages and disadvantages (countermeasure 1.3).

Group	Issue	Strength
Advantages
All	Safety is the primary advantage noted.	Many
Disadvantages
Young males	Some drivers might actually speed up in response to the warning if they felt they were close enough to go through the intersection before the light changed.	Some
All	It might give drivers a false sense of security, be distracting/confusing, or be hard to see by the side of the road.	Few

Countermeasure 1.4: Intersection Collision-Warning Systems

Table 59. Would implementing this countermeasure improve safety (countermeasure 1.4)?

Group	Opinion	Strength
Washington, DC	They think it would work.	About 3/4
Chicago, IL, and Seattle, WA	They are receptive to the basic idea.	About half
All	They think that drivers would definitely stop if they saw this.	Many

Table 60. What are some of the implementation issues (countermeasure 1.4)?

Group	Issue	Strength
All	It has potential in a different form but is "too much" in its current implementation.	Some
All	Having fewer lights or eliminating the lights embedded in the pavement would be an improvement.	Many
All	Placing the warning lights before intersections, adding sounds, or using yellow lights might make it more effective.	Some
All	It would require a big campaign to let everyone know what it is and what drivers should do when they see it.	Some
All	There would be skepticism over whether the technology actually works and if it would provide an early enough warning to stop in time.	Some
All	It might be confusing to drivers and they may not know what to do.	Some

Table 61. Advantages and disadvantages (countermeasure 1.4).

Group	Issue	Strength
Advantages
All	Safety is the primary advantage noted.	Many
Disadvantages
All	The signals and flashing lights might "freak out" certain drivers and actually cause more crashes if they stopped short.	Many
All	They are concerned that so much taxpayer money would be spent addressing the actions of irresponsible drivers and lawbreakers—even if it was to protect others.	Many
All	This solves the wrong problem and does not address the drivers that would go through the light.	Few
All	It might make some drivers lazy and more likely to depend on these to look out for them.	Some

Table 62. How does this system compare to an in-vehicle warning system (countermeasure 1.4)?

Group	Issue	Strength
All	Drivers are less receptive to the idea of having the warning system in their automobiles.	Most
All	Unlike seatbelts, this countermeasure would not be useful unless everybody has one.	Most
All	This system would have the same impact in terms of startling some drivers, but at least with the infrastructure-based system, drivers would have a clear indication of why the lights are flashing.	Most
All	It would increase the costs of their car.	Few
All	It would be less effective because it might not warn the redlight runner, as is the case with the intersection-based system.	Few
Older	There should be sound in addition to lights.	Few

Countermeasure 2.1: Protected left-turn lights

Table 63. Would implementing this countermeasure improve safety (countermeasure 2.1)?

Group	Opinion	Strength
All	These are very effective at improving safety, and drivers would like to see them at all busy intersections.	Almost All

Table 64. What are some of the implementation issues (countermeasure 2.1)?

Group	Issue	Strength
All	They sometimes have problems if the traffic signal has both a green light and a green arrow at the same time.	Few
All	The light could be improved by including a sensor that only activates the turn arrow when someone is in the turning lane.	Few
All	Stopping pedestrians from crossing when drivers had the green arrow would be an improvement.	Few

Countermeasure 3.1: Automatic gap detection

Table 65. Would implementing this countermeasure improve safety (countermeasure 3.1)?

Group	Opinion	Strength
All	This is a good idea and would improve safety.	About 1/3
Chicago, IL, young females	It would be helpful and it makes sense.	Almost all
All	Drivers are concerned about how trustworthy the system is and would prefer to judge gap safety "with their own eyes."	Many
All	They would prefer other countermeasures, such as traffic light, traffic island, or "suicide" lane.	Some

Table 66. What are some of the implementation issues (countermeasure 3.1)?

Group	Issue	Strength
All	This approach would be most effective if it only addressed the oncoming traffic from the right and would be confusing if it addressed both directions.	About half
All	They are concerned that the timing would not work.	Many
All	They are uncertain if it takes into account different weather conditions and how fast their car can accelerate.	Some
All	The system should be designed to accommodate the lowest common denominator.	Some
All	The warning should be accompanied by a continuous or contingent blinking light indicator on the crossing road so that oncoming traffic would be notified that someone might be turning in front of them.	Few
All	The warning signal should blink when it is safe to turn instead of when it is unsafe.	Few
All	The sign would be too difficult to read because the text is too small or too verbose.	Few
All	The flashing yellow is confusing, and drivers might not understand it.	Some

Table 67. What are some of the advantages and disadvantages (countermeasure 3.1)?

Group	Issue	Strength
Advantages
All	Safety is the primary advantage noted.	Many
Disadvantages
All	Drivers might get lazy or dependent upon the sign and not check the actual gap properly.	Some
All	There is no need for it, or drivers are likely to ignore it in favor of their own judgments.	Some

Table 68. Gap advisory system (countermeasure 3.1).

Group	Issue	Strength
Washington, DC	They are receptive to the idea and think that it would be helpful.	Many
Chicago, IL, and Seattle	They think that it would not help or make a difference to drivers.	Almost All

Countermeasure 3.2: Synchronized Adjacent Traffic Signals

Table 69. Would implementing this countermeasure improve safety (countermeasure 3.2)?

Group	Opinion	Strength
All	It is an effective approach and will improve safety at the intersection.	About 3/4
All	It would be more effective than automated gap detection.	Many

Table 70. What are some of the implementation issues (countermeasure 3.2)?

Group	Issue	Strength
All	It would be even better if sensors judged when it was needed so the traffic wouldn’t get needlessly backed up or stopped.	Many

Table 71. What are some of the advantages and disadvantages (countermeasure 3.2)?

Group	Issue	Strength
Advantages
All	Safety is the primary advantage noted.	Many
Disadvantages
All	Drivers would still have to be aware of people turning on red lights at the adjacent intersections or coming from driveways and other side streets.	Few

Countermeasure 4.1: Intersection Rumble Strips

Table 72. Would implementing this countermeasure improve safety (countermeasure 4.1)?

Group	Opinion	Strength
All	This is an effective countermeasure and it would improve safety.	About half
All	This is not an effective countermeasure because the potential problems outweigh the benefits (see below).	About half
All	It would help drivers refocus their attention on the road and on the intersection ahead.	Many
All	It does not address the situation because fatigue and distraction are not the primary problems.	Some

Table 73. What are some of the implementation issues (countermeasure 4.1)?

Group	Issue	Strength
All	It would not be necessary at every intersection, but helpful at dangerous intersections.	Many
All	Drivers would get use to them, and they would lose their effectiveness if they were at every intersection.	Most
All	Rumble strips are better suited for the sides of highways and the approaches to toll booths because they are more frequently encountered in those situations.	Some
All	It might make people slow down, which they should not always do in intersections, especially when the light is green.	Some
All	It implicitly sends the message to drivers that it is acceptable to be distracted.	Few

Table 74. What are some of the advantages and disadvantages (countermeasure 4.1)?

Group	Issue	Strength
Advantages
All	Safety is the primary advantage noted.	Many
Disadvantages
All	It would be very annoying because the rumble strips are loud and would rattle their cars or make them think they have a flat tire.	Many
All	It will cause additional wear and tear on their cars and tires.	Some

Countermeasure 4.2: Improved Skid Resistance

Table 75. Would implementing this countermeasure improve safety (countermeasure 4.2)?

Group	Opinion	Strength
All	It would be effective and would improve safety.	Most
All except Washington, DC, older	It is preferable to rumble strips, and it would be more effective in improving safety than rumble strips.	Most
All	A combination of intersection rumble strips and improved skid resistance would be the most effective implementation.	Many

Table 76. What are some of the implementation issues (countermeasure 4.2)?

Group	Issue	Strength
All	It would be important that this countermeasure be consistently implemented so that drivers could tell when it is present in case they must rely on it.	Few
All	It should not be at every intersection, only at dangerous ones.	Many
All	The skid-resistant treatment would have to start back far enough so that it would be available for all the drivers that need to stop—otherwise, lead vehicles on the treatment would stop more quickly than following vehicles not on the treatment, making rear-end collisions more likely.	Some

Table 77. What are some of the advantages and disadvantages (countermeasure 4.2)?

Group	Issue	Strength
Advantages
All	Safety is the primary advantage noted.	Many
All	It would work well on snow and ice.	Some
Disadvantages
All	Drivers might come to rely on it, which might falsely shorten their perception of what their reaction time is.	Few

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Page Owner: Office of Research, Development, and Technology, Office of Safety, RDT

Topics: research, safety, human factors, intersection safety
Keywords: research, safety, driver attitudes and behaviors, focus groups, intersection safety, engineering countermeasures
TRT Terms: Roads--Interchanges and intersections--Safety measures--Evaluation, Motor vehicle drivers--Attitudes, Drivers, Interchanges and intersections, Attitudes, Behavior
Scheduled Update: Archive - No Update needed

This page last modified on 03/08/2016