Aggressive Driving

Description of Strategies


Two objectives have been identified for addressing aggressive driving:

  1. Deter aggressive driving in specific populations and at specific locations (this includes those with a history of such behavior).
  2. Improve the driving environment to eliminate or minimize the external “triggers” of aggressive driving.

Both populations and specific individuals among whom aggressive driving appears to be over-represented are to be identified. In addition, geographical areas where such events most frequently occur are to be identified. The approach uses three components:

  • Crash records and observations to identify populations and geographical areas,
  • Driver records to identify individuals displaying a propensity toward aggressive driving, and
  • Observations to examine the driving environment to identify “triggers” that could set off aggressive driving.

Where populations or geographical areas are over-represented, two approaches are appropriate for taking corrective action:

  • Identify means of reaching the populations through targeted education, public information, and sanctions.
  • Reinforce education and public information through enforcement.

Where “triggers” in the roadway environment are identified, efforts are to be directed at eliminating or modifying the problems in the driving environment. Two key approaches are proposed:

  • Make changes in roadways and traffic control devices to improve the flow of traffic.
  • Reduce the frustrations arising from delays.

For all of these approaches, the law enforcement community plays a key role. They are in a position to stop acts of aggressive driving when they occur, as well as help identify contributing environmental factors. However, with the exception of repeat offenders, laws and enforcement represent an intermediate step that alone will not solve aggressive driving. Achieving the objectives requires cooperation among multiple stakeholders, including legislative, education, law enforcement, the courts, and the community.

Exhibit V-1 summarizes the objectives and associated strategies. Each strategy is described in detail below.

Objectives and Strategies for Addressing Aggressive Driving



4.1 A—Deter aggressive driving in specific populations, including those with a history of such behavior, and at specific locations

4.1 A1—Target enforcement


4.1 A2—Conduct educational and public information campaigns


4.1 A3—Educate and impose sanctions against repeat offenders

4.1 B—Improve the driving environment to eliminate or minimize the external "triggers" of aggressive driving

4.1 B1—Change or mitigate the effects of identified elements in the environment


4.1 B2—Reduce nonrecurring delays and provide better information about these delays

Explanation of Strategy Types

The strategies listed above and described in detail below are those considered unique to the aggressive-driving emphasis area. These strategies fall into one of two categories, either “tried” (T) or “experimental” (E), relative to how the strategy will impact aggressive driving. (A third strategy category, “proven” [P], is not used because although the strategy may have been effective in other applications—e.g., occupant restraint—it has not been evaluated and found effective for aggressive driving. Therefore, the reader should be prepared to exercise caution in many cases before adopting a particular strategy for implementation.)

The definitions are as follows:

  • Tried (T): Those strategies that have been implemented in a number of locations, and may even be accepted as standards or standard approaches, but for which there have not been found valid evaluations. Such strategies—while in frequent, or even general, use—should be applied with caution, carefully considering the attributes cited in the guide, and considering that while they may have been tried for other purposes, the application to aggressive driving is relatively new and not well evaluated as yet. Implementation can proceed with some degree of assurance that there is not likely to be a negative impact on safety and very likely to be a positive one. As the experiences of implementation of these strategies continues under the AASHTO Strategic Highway Safety Plan initiative, appropriate evaluations should be conducted, so that effectiveness information can be accumulated to provide better estimating power for the user, and the strategy can be upgraded to a “proven” one.
  • Experimental (E): Those strategies that are ideas that have been suggested, and at least one agency has considered sufficiently promising to try on a small scale in at least one location. While this definition generally applies in the set of guides for implementing the AASHTO Strategic Highway Safety Plan, it must be understood in a slightly different manner here. The strategies that are classified as experimental in this guide are ones that have been tried to a good degree. However, they have not been applied in the context of mitigating aggressive driving. Therefore, they are considered experimental. Where they are considered, their implementation should initially occur using a very controlled and limited pilot study that includes a properly designed evaluation component. Only after careful testing and evaluations show the strategy to be effective should broader implementation be considered. As the experiences of such pilot tests are accumulated from various state and local agencies, the aggregate experience can be used to further detail the attributes of this type of strategy so that the strategy can ultimately be upgraded to a “proven” one.

Specific Objectives

4.1 A—Deter Aggressive Driving by Specific Populations, Including Those with a History of Such Behavior, and at Specific Locations

The objective here is one of general deterrence, but in a targeted manner. Treating specific age groups is one example. The procedure consists of identifying a series of violations exemplifying the specific problem of aggressive driving in a particular area, or of a specific subset of drivers, and then instituting an intensive program aimed at changing the undesirable behaviors. This type of analysis also provides useful input for Objective 4.1 B by helping to identify triggers for the aggressive behavior that may be present in the roadway environment. In order to meet this objective, any program needs to be directed by a multidisciplinary group. It can involve the use of educational and public information techniques, along with coordinated enforcement.

Addressing aggressive driving at specific locations may require a top-down approach to help focus efforts, especially where state funds are being made available. In this process, a problem should be recognized first at the state level, by identifying political jurisdictions within which there seems to be overrepresentation. The local jurisdiction is then consulted to help target specific locations or populations. This is the approach that the Florida Department of Transportation (see Appendix 2) has taken. However, this process may also be conducted starting at the local level.

In addition, there are drivers that habitually drive aggressively. The objective here is to intervene in a way that minimizes or eliminates aggressive driving behaviors. Methods of education and behavior modification are needed to help the habitual offender invoke self-discipline. Additionally, a perception must be created that repetition of violations will bring sanctions. In some cases, sanctions such as licensing actions may be part of the behavior modification. However, research elsewhere questions the overall value of license sanctions in behavior modification (for more information, see Volume 2 of this report).

The key stakeholders to be involved in achieving this objective are law enforcement, courts, driver services, and the media. Others are shown in Appendix 7.

4.1 B—Improve the Driving Environment to Eliminate or Minimize the External “Triggers” of Aggressive Driving

This objective targets conditions on the highway that have been identified as causing frustration to the level that aggressive acts of driving are committed. This is a topic about which little has been written, except by Shinar (1998), who observed behavior at traffic signals that provided minimal green times for certain phases. However, a large body of psychological literature links frustration to aggression.

To meet the objective, aspects of the driving environment need to be identified that create a significant probability that the targeted behaviors will occur. This is an uncharted area that currently requires a large degree of judgment on the part of those planning the program. Observation of behavior at candidate sites is likely to be the best indicator, given current knowledge. Programs can be put in place to modify, where possible, or at least minimize, these external elements. A key outcome from this objective is minimizing frustrations caused by elements not within the driver’s control.

The key stakeholders in this objective are law enforcement agencies, departments of transportation, and citizen public action organizations. Others are shown in Appendix 7.

Related Strategies for Creating a Truly Comprehensive Approach

To create a truly comprehensive approach to the highway safety problems associated with this emphasis area, four types of related strategies should be included as candidates in any program planning process. The first two involve public information and education and traffic law enforcement. Specific strategies of these two types are explicitly described in the next section.

  1. Public Information and Education (PI&E) Programs: The primary experience with PI&E campaigns in highway safety is to reach an audience across an entire jurisdiction or a significant part of it. However, there is evidence that suggests that public information by itself will not be effective.1 While programs related to aggressive driving are too new to have been adequately evaluated, seatbelt and occupant restraint programs have been operational for many years. Examples of how to conduct enforcement and education programs for seatbelt usage can be found in the NHTSA document “Occupant Protection Special Traffic Enforcement Program Evaluation.”2
  2. Enforcement of Traffic Laws: When traffic laws are vigorously enforced, with well trained officers supported by the courts, the frequency and severity of highway crashes or injuries linked to their violation can be significantly reduced. NHTSA’s “Aggressive Driving Enforcement: Strategies for Implementing Best Practices,”3 focuses on programs as well as processes used by law enforcement throughout the United States. Most programs cited, however, are essentially examples of intensive traffic law enforcement. In only a few cases have they been directed toward well-defined aggressive driving behaviors. Moreover, most have not been evaluated for effectiveness.
  3. Strategies to Improve Emergency Medical and Trauma System Services: Treatment of injured parties at highway crashes can have a significant impact on the level of severity and length of time during which an individual spends treatment. This is especially true when it comes to timely and appropriate treatment of severely injured persons. Thus, a basic part of a highway safety infrastructure is a well-based and comprehensive emergency care program. While the types of strategies that are included here are often thought of as simply support services, they can be critical to the success of a comprehensive highway safety program. Therefore, for this emphasis area, an effort should be made to determine if there are improvements that can be made to this aspect of the system, especially for programs that are focused upon location-specific (e.g., corridors) or area-specific (e.g., rural area) issues. As additional guides are completed for the AASHTO plan, they may address the details regarding the design and implementation of emergency medical system strategies.
  4. Strategies Directed at Improving the Safety Management System: The management of the highway safety system is foundational to its success. There should be in place a sound organizational structure, as well as an infrastructure of laws, policies, etc., to monitor, control, direct, and administer a comprehensive approach to highway safety. For aggressive driving, the roles of driver services administration, law enforcement, courts, and traffic engineering are critical. Driver services need to be able to identify drivers who consistently appear on the records for violations that can indicate aggressive driving. The police need to enforce laws of which the violation has been shown to lead to aggressive driving crashes. Courts need to treat cases of aggressive driving as a serious driving violation, ensuring appropriate outcomes that will act as a future deterrent. Finally, traffic engineers need to act in minimizing elements of the driving environment, such as uncoordinated traffic signals, which may trigger aggressive driving.
  5. Strategies that Are Detailed in Other Emphasis Area Guides: Any program targeted at the safety problem covered in this emphasis area should be created having given due consideration to the inclusion of other applicable strategies covered in other guides. For aggressive driving, Volume 2 of this report is important because aggressive drivers who often commit traffic violations also are likely to have had their driver’s licenses suspended or revoked.

Objective 4.1 A—Deter Aggressive Driving by Specific Populations, Including Those with a History of Such Behavior, and at Specific Locations

Strategy 4.1 A1—Target Enforcement (T)
Process: Law enforcement targeted to specific aggressive driving behaviors that have been shown to contribute to crashes, as well as identifying possible external contributing factors.

Expected Outcome: Reduction in ongoing acts of aggressive driving and resulting crashes. Evaluation: Comparison of crashes that have been caused by aggressive driving at the targeted areas and measures of change in aggressive driving behavior.

This approach is most frequently employed for addressing aggressive driving. The intent is to target locations rather than habitually aggressive drivers. It begins by selecting a site identified as having a problem with aggressive driving. This is often based on observations or on the frequency of certain types of crashes. A highly visible and intensive enforcement effort is designed and implemented. To be effective, this effort must concentrate on a set of driving actions and violations thought to have specific relevance to aggressive driving at the selected area.

It is important that candidate locations for this strategy first be screened to determine (1) if there might be factors present in the roadway environment that would trigger aggressive driving and (2) which of these factors can be readily fixed. Unless the enforcement were vigorous and continuous, these locations are not likely to be effectively controlled by an enforcement effort, as long as the environmental triggers remain. In such cases, strategies under Objective 4.1 B should be considered for addressing the problem.

Research in the area suggests the importance of enforcing in such a way that those who drive aggressively have a high expectation of being apprehended. A coordinated publicity campaign needs to accompany the program.

Evaluation of this strategy can be conducted by both observation of driving behavior and longer-term efforts to assess changes in crash frequency. Effectiveness of enforcement targeted only to aggressive driving generally has not been measured. The exceptions are for some programs in Milwaukee, Wisconsin (see Appendix 1). The Pennsylvania Department of Transportation has been partnering with local communities to conduct aggressive driving programs based on analysis of crash data.4

This strategy is not likely to interfere with most others and may be performed in combination with other enforcement-oriented efforts, where appropriate. When combined with other strategies, especially other enforcement strategies, evaluation of effectiveness of the specific strategy may not be feasible unless special methods of research design are employed. Most importantly, intensive enforcement programs generally have been found to be effective in other areas of traffic law enforcement. However, because they require extensive resources, they are not usually sustained.

Strategy Attributes for Targeted Enforcement Aimed at Aggressive Driving (T)


General population of drivers at a defined location characterized by observed aggressive driving behavior or high crash rates where aggressive driving appears to be a principal contributor.

Expected Effectiveness

This strategy has been tried as a means of reducing crashes resulting from aggressive driving. While some agencies have reported success, there is not adequate published evidence of the effectiveness of the strategy for controlling aggressive driving, or reducing crashes involving aggressive driving.

Examples of agencies that have recently operated aggressive driving programs include the following:

  • Florida Department of Transportation has examined fatal crash reports and identified counties in which such crashes appear over-represented (see Appendix 2).
  • Washington State Patrol operates an Aggressive Driver Apprehension Team (ADAT) (see Appendix 3). In addition to program specifications, they have produced a video for public presentation.
  • Pennsylvania DOT.
  • Milwaukee, Wisconsin (see Appendix 1).

Keys to Success

Concentration of actions that meet the definition.

Cooperative venture with courts and judicial system (see the Halt Aggressive Driving H. A.D. program in Lubbock, Texas, Appendix 4).

Need for good publicity, with the cooperation of both print and broadcast media, is very important, as noted in Strategy 4.1 A2.

Public support (Lubbock, Texas, Citizens’ Traffic Commission, see Appendix 4).

Close working relationship with traffic engineers to identify operational factors potentially influencing behavior.

Potential Difficulties

Failure to involve the public in planning the program.

Arriving at a clear, operational definition for locating aggressive driving sites.

Enforcement that is not related to the stated problems. An ongoing problem with most of the current efforts has been that

  1. They have concentrated on speeding, rather than the sort of driving behaviors unique to aggressive driving and
  2. They aggressively enforce all violations for a short period, then change their operations, thereby not likely affecting aggressive driving.

Appropriate Measures and Data

Process measures:

  • Numbers and types of citations.
  • Numbers of officers on special patrol.
  • Officer time on special patrol.
  • Ratio of time to the frequency of issuance of citations for aggressive activities.
  • Disposition of the aggressive driving citations.

Performance measures:

  • Before and after assessment of frequency and severity of crashes, by type.
  • Observed changes in aggressive driving behavior.

Filming could be used to both acquire traffic operations data and observe driver behavior.

Associated Needs

If the enforcement involves the use of automated equipment, such as red-light running cameras, then vendors and others with technical expertise would need to become involved in the project. Calibration of the equipment may significantly impact the outcomes of the strategy.

The data needed to perform appropriate assessments may not be available from existing sources. Special arrangements may be needed for the appropriate agencies to establish additional data-collection protocols prior to implementation, during the program, and for a period after it has ended. In some cases, it may be necessary to hire additional personnel, or a private organization to supplement the limited resources at a particular agency.

Organizational, Institutional, and Policy Issues

Agreement must be reached on a common definition of “aggressive driving.” The introduction to this guide provides suggestions.

Close working arrangements among traffic law enforcement, courts, and traffic engineering need to be in place. In many areas, cooperation between different police agencies will be required. An active joint task force is being conducted in Lee County, Florida (see Appendix 5). The courts need a judge with a strong commitment to the program (e.g., Lubbock, Texas; see Appendix 4).

With the exception of automated enforcement approaches, this sort of program is labor intensive. Therefore, issues involving the allocation of personnel will arise. This would be the case even if overtime for officers were funded from grants. Where police personnel shortages exist, traffic enforcement functions are usually affected more than areas such as violent crime prevention, due to priorities.

Early involvement of all stakeholders is a must. They should have input at the beginning of the planning for a program.

Issues Affecting Implementation Time

A program “champion” is needed, who has the position and time to spend on facilitating the implementation of a program.

Given the need for inter-organizational cooperation, development of enforcement strategies, measuring the “before” conditions, and gaining public cooperation, a minimum period of six months is likely to be needed prior to starting enforcement.


While the costs of a given program will be quite specific to local conditions, a number of elements of that cost can be identified. These include pay/overtime for police officers, training expenses, marketing efforts, supplies, and evaluation expenses.

Training and Other Personnel Needs

Because it is essential that the program target a predetermined set of aggressive driving behaviors, training of police officers, prosecutors, and judges will be required. This will focus upon what is meant by aggressive driving at both the conceptual and operational levels. For police it is most likely that this will require roll-call training techniques such as a videotape.

Legislative Needs

Although a number of jurisdictions have passed a specific law aimed at aggressive driving (e.g., Arizona, Delaware, and Colorado), these laws concentrate on commission of multiple traffic violations. This approach can include many instances where aggressive driving is not occurring. It is more appropriate to institute a means for indicating when a citation was issued for aggressive driving and to obtain appropriate support from prosecuting attorneys and judges using current driving statutes.

If automated enforcement approaches are employed, it is highly likely that legislation would be required. Most state laws require that the driver of a vehicle be cited rather than the owner. Automated enforcement works best when identifying the vehicle and thus the registered owner.

Strategy 4.1 A2—Conduct Educational and Public Information Campaigns (T)
Process: Convey two basic types of information about aggressive driving to the public.

  1. Learning to cope with situations where other drivers are displaying aggressive driving behaviors.
  2. Helping drivers recognize and modify their own tendencies toward aggressive driving.

Expected Outcome: Educational programs that reach the targeted audiences and generate widespread media exposure.

Evaluation: Surveys to determine media penetration and public knowledge of the message.

Effective public education and information campaigns need to be run in conjunction with intensive enforcement. Studies elsewhere5 suggest that by themselves, the effectiveness of public information and education programs on changing driving behavior is limited. The public information and education (PI&E) agenda will include details of the enforcement program and chart its progress. The city of Milwaukee, Wisconsin’s, program (see Appendix 1) is a good example of coordinating public information with targeted enforcement.

Other examples from programs to reduce driving under the influence (Verschuur, 1993) and increase occupant restraint usage (Smith, 1987) have pointed to programs of public information and education that have acted in concert with enforcement. The outcomes from both suggest that combing the two strategies has a better likelihood of success than either alone.

The campaign should concentrate on communicating specific information and examples in a way that would be easily understandable and attractive to the intended audience of drivers in the selected area. While the actual mix of media selected for the campaign ultimately will be a local decision, it is expected that the bulk of the campaign would be conducted on radio and television. Lee County, Florida, provides an excellent example of cooperation with the broadcast media (see Appendix 5).

Radio, especially during morning and afternoon drive times, seems the best-suited medium. Being able to communicate with drivers while they are driving has the potential for immediately affecting behavior. Another advantage of employing radio is that the known demographics of various shows allow for an effort to be targeted at a particular group, such as younger males who appear to play a disproportionate role in the aggressive driving problem. Television provides highly visual approaches for dramatizing aggressive-driving incidents.

The campaign must be carefully planned, and the spots should be professionally produced.

Consumers will tend to discount anything that appears amateurish or simplistic. (For an example of a professional approach to material by Washington State Patrol, see Appendix 3). Efforts should also be made to secure news coverage of the campaign, affording greater exposure without increasing costs. Lubbock, Texas, has achieved substantial results at minimal costs (see Appendix 4).

Evaluation of the campaign consists mainly of attempts to determine drivers’ exposure and responses to the messages. General assessment of public information programs has shown them to have limited effect on actual behavior except where they are paired with enforcement. While it would be desirable to assess the effect on actual driving behavior through changes in violations and crashes, the difficulty of isolating such effects probably makes this infeasible.

Education needs to be directed toward newer drivers and needs to stress how they can better control their behavior. Current approaches often tend to stress how to prevent escalation of aggressive driving rather than eliminating the original behavior. Lubbock, Texas, has found some success in addressing aggressive driving in the middle schools, before the students become drivers, and at the college level.

Strategy Attributes for Conducting Educational and Public Information Campaigns (Aimed at Aggressive Driving) (T)


All drivers in a given geographic area. This would be an area that is experiencing a high level of aggressive driving, as determined by such indicators as crashes seemingly related to aggressive driving, observations by law enforcement or other highway safety agencies, or a number of credible complaints from road users indicating the existence of perceived aggressive driving.

Expected Effectiveness

This strategy has been tried as a means of reducing crashes resulting from aggressive driving. While some agencies have reported successful public information campaigns and linked those campaigns to targeted enforcement, there is little published evidence of effectiveness of this strategy. Good public information (PI) campaigns heighten awareness of a problem and garner high approval ratings. On the other hand, assessing the effectiveness of a large-scale PI program on actual driving behavior is almost impossible.

Testing students for awareness of the problem and for knowledge may be the only available evaluation tool.

Keys to Success

The program materials must be professionally done and aimed at the designated target audiences. The materials must focus on specific driving behaviors rather than general appeals to not drive in an aggressive manner. Those running the program must cultivate and maintain good contacts with both print and broadcast media. Drivers must be given suggestions on specific skills to help them cope with anger both in other drivers and in themselves. Campaigns should center on local conditions and situations familiar to the intended target population.

Education must be geared to the specific audience. It must concentrate on eliminating behaviors that lead to aggressive driving.

Some examples of these key elements include

  • Using donated unsold billboard inventory (Lubbock, Texas; see Appendix 4).
  • Television donating production facilities; local sports heroes donating time (Lubbock, Texas; see Appendix 4).
  • Establishing positive, ongoing relationships with both radio and television stations, especially their news departments (Lee County, Florida; see Appendix 5).
  • Professionally produced material such as videos for public presentation (Washington State Patrol–see Appendix 3).
  • Educating younger (middle school) and older students (college) (Lubbock, Texas; see Appendix 4).

Potential Difficulties

Because production and air time for advertising are a high cost, a program must be able to garner a significant amount of interest from the media to secure a maximum amount of air time for the cost. Educational efforts in the schools face competition for students’ time. PI&E efforts need to

  • Avoid banal slogans,
  • Focus on skills and attitudes that will help drivers cope with the difficulties they encounter while driving, and
  • Make the material understandable and attractive to the potential audience (e.g., translate material into the dominant language of the target audience).

Appropriate Measures and Data

For process analysis, the frequency, time and market of each of the messages should be documented. In addition, approaches are needed for determining the number of people who are exposed to, and become aware of, the messages; characteristics of the people being exposed; and their reactions to the campaign. This testing should be done periodically throughout the campaign so that changes can be made in response to specific findings.

The impact analysis for a program such as this can be performed by assessing a sample of people in the target area regarding their attitudes and knowledge relating to aggressive driving. This assessment would require a pretest at the start of the program and another at the conclusion so that comparisons could be made. This approach also is of value for educational efforts.

Associated Needs

The active support of “gatekeepers” in the media is essential. Skilled professionals are needed to create the materials employed in the campaign. Use of those with expertise in listener and viewer characteristics will allow for optimal targeting of messages.

Organizational, Institutional, and Policy Issues

Assuming a commitment on the part of the agency sponsoring the campaign, there do not appear to be significant issues on this level. One potential issue that was mentioned by the director of the PI&E program run by the California Highway Patrol was difficulties stemming from state contracting laws in using professional talent for the creation of materials.

Issues Affecting Implementation Time

Time required to start the program will depend upon time needed to prepare media materials, perform pretests, and secure time and space for the actual dissemination of the materials. At least six months could be required to launch a successful program. Similarly, educational programs for schools can take 6 or more months to develop, test, schedule, and implement.


Most programs such as this are expensive. The largest costs are the professional talent required for the preparation of the materials, as well as costs for airtime and print media space. Creating newsworthy events to garner free time and space can reduce these costs. The Lubbock, Texas, program (see Appendix 4) has been able to sustain itself with very low costs, using creative approaches to producing and airing materials.

Training and Other Personnel Needs

For educational programs, there is a need to train the instructors in the material and its presentation.

Legislative Needs

None identified.

Strategy 4.1 A3—Educate and Impose Sanctions Against Repeat Offenders (E)

Processes: (1) Identify drivers with frequent crashes and citations resulting from aggressive driving. (2) Conduct courses using structured curricula that are designed to counter specific driving behaviors and teach anger management. (3) Institute driver sanctions, including license suspension/revocation and/or vehicle impoundment, especially for repeat offenders with serious offenses.

Expected Outcome: Reduction in ongoing acts of aggressive driving by targeted individuals.

Evaluation: Compare driver records before and after entry into the program or with drivers who have similar records but are not enrolled.

The general thrust of this program is to combat the problem of aggressive driving by modifying the behavior of those who frequently drive in an aggressive manner. The program would take a form quite similar to that employed in remedial defensive driving programs or those aimed at DUI offenders. The intent is to help these drivers understand the dangers inherent in aggressive driving and, most importantly, ways to recognize and change their negative driving behaviors.

This is an experimental strategy since, although similar programs exist, they have not been targeted at aggressive drivers. Use of this strategy should be made with caution and begun by using a pilot implementation that can be carefully evaluated.

The program would make use of classes having a structured curriculum that allows students to learn what constitutes aggressive driving in themselves and others and the best ways to counter it. In addition to specific driving behaviors, tactics aimed at anger management would be included. It is extremely important that the classes not be lecture based, but rather employ a facilitation model. The National Safety Council offers a course, “Defensive Driving Course—Attitudinal Dynamics of Driving (DDC-ADD),”, that is an example (no product endorsement intended).

Because students will be selected on the basis of an aggressive driving record, it will be important to identify the types and combinations of violations that will be considered indicative. The drivers selected will have to be induced to take the class. In most cases this would come from either a court order or a motor vehicle agency allowing attendance as a substitute for a license action.

Evaluation of this strategy needs to be done at the individual level. Driving records for those completing the class would be tracked, and their pre- and post-class performance compared. Use of a treatment-control study may be done if carefully developed.

Strategy Attributes for Educating and Imposing Sanctions Against Repeat Offenders (E)


Those drivers showing a history of violations indicating a pattern of aggressive driving.

Expected Effectiveness

There are no valid evaluations of this strategy, especially where it is related to the habitual aggressive driver. The general finding from programs directed toward multiple traffic law offenders is that the programs show some effectiveness in reducing violations, but not a significant impact on crashes. However, because this proposed program would introduce new elements such as anger management, the issue of its effectiveness becomes an empirical question that can be answered only when the strategy is implemented in a number of places.

Keys to Success

The program must use materials aimed specifically at the issue of aggressive driving. They must derive directly from a detailed analysis of the specific driving attitudes and behaviors that the program is intended to modify.

Legal steps should be in place, aimed at compelling participation by those designated. Driving sanctions, as options, need to be in place; therefore, the courts play a critical role.

Highly skilled instructors are needed. They should be carefully trained and monitored.

Potential Difficulties

The cooperation of the judiciary is required to mandate that defendants, having a clear history of aggressive driving violations, take the course or be sanctioned as appropriate.

Appropriate Measures and Data

Process measures could include total number of aggressive driving citations issued in the jurisdiction(s), number of aggressive driving citations for which the driver was directed to a course, number of multiple offenders, etc.

Performance measures include pre- and post-class assessments of knowledge, attitudes, and intended behavior relating to aggressive driving, time to next citation for aggressive driving (failure analysis), and crash reduction (crashes where the principal contributor was aggressive driving).

Associated Needs

Expertise in the design of educational approaches to eliciting behavior change would be required.

Additional assistance is needed to acquire and process driver histories to select those who should be sent to courses.

Organizational, Institutional, and Policy Issues

Courts in the jurisdiction must be committed to ensuring that the drivers meet established entry thresholds to the program. A possibly complementary approach would be for drivers to be sent to the program through administrative actions of state driver licensing authorities. It will be necessary for the courts and law enforcement agencies to agree to provide data needed for program assessment.

Alternative sanctions must also be employed to keep the sanctioned individuals from operating a vehicle if the offender continues to drive aggressively or does not enter the required program. Sanctions similar to those for driving without a license may be considered. For further details on this, see Volume 2 of this report.

Issues Affecting Implementation Time

The need to first create materials, and then train instructors, will be a major determinant of implementation time. Additionally, legislative and organizational changes might be required. It would appear that 12–18 months would be a minimum period required to implement a program such as this.


A major up-front cost for the program would be the development of materials and the training of instructors. One source could be NHTSA 402 Funds. (

Once the program was running, it could become user-funded and incur no additional costs and might even receive enough funds to pay back the materials development.

Training and Other Personnel Needs

Training would be required for the instructors teaching the course. Training would also be needed for judges and other court personnel in the procedures and requirements for enrolling drivers into the program. Personnel would also be required to administer and evaluate the program.

Police need to be trained in detecting aggressive driving, giving special emphasis to identifying repeat offenders.

Legislative Needs

If the program were court-based, it would probably be possible to institute it without specific legislation. However, having legislation requiring the course for drivers would be helpful. If the program were based in a motor vehicle department, specific legislation probably would be required. Legislation may also be needed if administrative adjudication is desired but not yet authorized.

Objective 4.1 B—Improve the Driving Environment to Eliminate or Minimize “Triggers” of Aggressive Driving

Strategy 4.1 B1—Change or Mitigate the Effects of Identified Elements in the Driving Environment (E)

Process: Identify factors in the driving environment that may contribute to aggressive driving and modify those factors.

Expected Outcome: Less aggressive driving triggered by factors external to the driver.

Evaluation: Measure instances of aggressive driving before and after implementing changes, as well as change in crash experience for those crashes involving aggressive driving.

While traffic engineers and highway designers have applied a whole variety of techniques for improving the operation and safety on roads, there is no documented evidence that such an approach will be effective in mitigating aggressive driving and the resultant crashes. The frustration-aggression model referred to above suggests that conditions may exist in the roadway environment that cause driver frustration and, therefore, aggressive driving. Thus, this strategy is considered experimental. It should be used with caution, beginning with small-scale trials in limited locations, using carefully designed evaluations.

Elements external to the driver can interact with, and significantly impact, the driver’s behavior. This generally occurs when these elements send a negative message (i.e., appear to impede travel unnecessarily). One example is the posting of speed limits that are so low for the roadway environment that they are not obeyed. While speeding is not, when occurring by itself, considered to be aggressive driving, it can occur in combination with actions directed at other vehicles that are maintaining the legal speed. Controlling aggressive driving that is the result of these conditions may not be possible using only enforcement and PI&E. It may ultimately take removal of the environmental factor to mitigate the problem (i.e., establishing an appropriate speed limit for the conditions).

Responses to a survey of aggressive driving scenarios from safety experts indicated that three actions closely linked to environmental factors were representative of aggressive driving: driving on the shoulders or medians, running red traffic signals (see and, and aggressive behavior in work zones (see

The corresponding environmental elements for these scenarios were

  • Insufficiently long exit ramps or left-turn lanes,
  • Improperly coordinated traffic signals, and
  • Unclear work zone traffic controls.

The respondents also indicated that while enforcement was necessary in these cases, corrective engineering actions could be the appropriate long-term solution.

As of mid-2002, there are no known or reported programs employing this specific strategy for mitigating aggressive driving. However, some potential influencing factors to consider are

  • Uncoordinated signals or sequencing that encourages speeding and red-light running (the Federal Highway Administration estimates that 75 percent of the installed traffic signals need modernization, including signal coordination).
  • Lack of signal optimization, encouraging red-light running, especially for turning movements.
  • Lack of adequate turn bays or exit ramp length, encouraging shoulder or median driving.
  • Lack of adequate entrance ramps, encouraging improper merging.
  • Speed limits not representative of road design and external factors that encourage their disregard.
  • Ineffective or undesirable traffic control in work zones.

The ITE A Toolbox for Alleviating Traffic Congestion and Enhancing Mobility (!.PDF, 1997) provides a comprehensive coverage of the variety of actions that may be taken to reduce congestion. Some key excerpts from this document appear in Appendix 8. Whereas some of the actions involve significant expense, a number of candidates can be accomplished at low to moderate cost and over a relatively short timeframe (e.g., traffic signal retiming). While the document provides estimates of safety effectiveness, the specific demonstrated ability of these strategies to mitigate aggressive driving is not addressed.

Strategy Attributes for Changing or Mitigating the Effects of Identified Elements in the Driving Environment (E)


Localized aggressive driving sites or corridors that may benefit from changes to traffic controls or roadway design, especially where those changes should alleviate the need for extensive traffic enforcement.

Expected Effectiveness

There are no valid evaluations of this strategy, especially where it is related to aggressive driving. Quantitative estimates are not available because of a lack of exemplary programs. However, the ITE Toolbox (!.PDF) advocates programs such as traffic signal coordination as a means of reducing congestion and its associated frustrations.

Keys to Success

Careful identification of target sites is important. A “team” approach is needed to draw upon engineering and enforcement specialists, as well as highway safety personnel. Usually, aggravating conditions are apparent. However, if driving behavior changes when enforcement is present, but reverts to its original condition as soon as enforcement is removed, the location may be a likely candidate for engineering intervention. Once aggressive driving sites are identified (see discussion about Strategy 4.1 A1), enforcement and engineering specialists need to identify possible contributors to the behavior. A pilot study may be appropriate to establish effectiveness quantitatively.

Potential Difficulties

Traffic engineering and highway design offices may not be willing to get involved with what they believe is a “law enforcement” problem. This becomes a distinct possibility when aggressive driving is defined in terms of violations of traffic laws.

Where local political decisions may have resulted in misapplication of traffic control devices or other aspects of road operation that contribute to the problem, it may be difficult to make the desired changes.

Appropriate Measures and Data

The process measure for this strategy is that recommended corrective action is appropriate and that the action was implemented properly.

Performance can be measured in the short term by the change in frequency and rate of observed aggressive actions after improvements are made. Ultimately, impact is measured by the change in crashes whose contributing factors include elements that are defined as aggressive driving.

Associated Needs

The joint involvement of different disciplines in determining the underlying contributing factors and then recommending and implementing corrective actions is critical. This step must be taken as part of targeted enforcement. Appendix 7 provides a list of stakeholders to consider as candidates to be involved.

Organizational, Institutional, and Policy Issues

Engineers and law enforcement personnel often view each other as distinct entities whose work does not overlap. This strategy requires that these views be replaced with an understanding that a team approach is needed. However, since the two operations are usually in separate agencies, there will be institutional issues to be dealt with.

Issues Affecting Implementation Time

The stakeholder team will require data and time to analyze conditions at sites. This may involve observations at locations. The scope of the effort, and the nature of the actions being considered, will determine the time required to implement a program. This will vary widely.


Costs can vary widely, depending upon the scope of the effort and specific action to be taken. For short-term actions, such as extending a painted turn median, the costs are relatively low. Implementing a coordinated signal system, especially one using demand responsive programming, can have relatively high costs. Funding may be available through sources such as NHTSA 402 ( or Congestion Mitigation for Air Quality (CMAQ) funds.

Training and Other Personnel Needs

Police need to receive more training in traffic engineering basics to help them recognize when effective enforcement might be limited because of roadway factors.

Legislative Needs

None identified.

Strategy 4.1 B2—Reduce Nonrecurring Delays and Provide Better Information about These Delays (E)

Process: Reduce or rapidly clear impediments to traffic flow, and provide accurate, timely information to travelers.

Expected Outcome: Less congestion, shorter delays resulting from incidents, and better traveler information concerning delays.

Evaluation: Reduction in travel time, reduction in time lanes are blocked, and assurance that information provided to motorists is timely and accurate.

Those whose responsibility it is to manage the highway system on a daily basis are constantly faced with challenges to keep traffic moving at a reasonable level of service. These challenges can arise from both planned events and unplanned incidents that occur. There are a variety of techniques available for managing traffic so as to both minimize the size of delay experienced by individual drivers, and the length of time over which roadways are affected. Minimizing delay will minimize frustration. Applying the frustration-aggression model discussed above, these efforts should reduce aggressive driving theoretically resulting from this nonrecurring periods of excessive delay. Furthermore, if information is provided to a driver who is in the midst of nonrecurring congestion, which helps reduce the driver’s level of frustration, it may also reduce the probability that the driver will act aggressively.

The term theoretical is used in the previous paragraph to emphasize that this is another experimental strategy. That is because the relationship between the presence of excessive nonrecurring delay and aggressive driving is not well documented. Therefore, efforts to minimize its impact are not proven to minimize aggressive driving. The relationships are logical, however, especially in the light of the underlying psychological theory. Thus, while the strategy is included here, it is with the caution to the potential user that it is not tested. Those who may wish to implement such a program are advised to start with a pilot implementation that is accompanied by a carefully designed evaluation before proceeding on any significant scale.

Recommendations for managing nonrecurring (incident) events have numerous references: for general use, by the Federal Highway Administration (1991); for freeways, by Mannering et al. (1992); and for arterial roadways, by Raub and Schofer (1997); in addition to the National Highway Institute (NHI) incident management course (

Accurate and timely traffic information is critical for motorists. This can be achieved through changes in procedures and training, especially for public safety personnel. In terms of incidents, the motorist needs to know what happened, where it is located, and how long it may remain a problem. Preferably, the motorist should know the travel conditions on alternate routes. Getting this information to the public can be done through better cooperation between the broadcast media and the information providers (e.g., public safety agencies) and through Web sites.

There are few examples in operation. However,

  1. The NHI Incident Management course stresses the need for responders to provide critical information.
  2. “Must Move” legislation (requiring drivers involved in minor crashes to move their vehicles off the roadway prior to calling the police) is in effect in a number of states (e.g., Texas,
  3. FHWA provides a site self-assessment tool for agencies that want to see how their incident management program rates. See Appendix 9.
  4. Additional information on incident management can be found at the site of the FHWA Office of Travel Management (
  5. The NYSDOT incident management system is described at
  6. Some key references on incident management, including a couple of guides produced by FHWA, are provided in Appendix 10.

For a more general reference on efforts directed toward reducing the effects of incidents, go to the ITE Traffic Incident Management (TIM) Committee site,

Strategy Attributes for Reducing Nonrecurring Delays and Providing Better Information about These Delays (E)


Both planned events and unplanned incidents that can be managed to minimize their impact and reduce the level of frustration in the affected drivers.

Expected Effectiveness

There has been limited research examining the effectiveness of demand management and none documenting the specific impact on aggressive driving. Although this strategy relates specifically to nonrecurring delay, it is well documented that incidents occur regularly (even several times daily) in heavily traveled corridors. Therefore, limiting these nonrecurring, but regular, delays even in one corridor may reduce significantly the level of daily frustration in travel for a significant subset of the driving population.

Careful planning and coordination of nonrecurring events, especially where multiple events may be planned in an urban center, can greatly reduce the potential for delay, which may mean that there will be reduced aggression exhibited by drivers. However, there is no evidence of this connection.

Tools such as the Highway Capacity Manual and related computer simulation programs may be used for predicting operational impacts of both planned events and unplanned incidents (e.g., testing alternative incident-response plans). However, the performance of strategies vis-à-vis crash reduction has generally not been established.

Keys to Success

  • Achieving a coordinated system of agencies for the region.
  • Training police and fire personnel to limit the time that an incident or event affects travel and provide for flow past the incident.
  • Establishing connection with, and involvement of, the media in incident and event management.
  • The success of the program will also depend upon public awareness and use of information sources.

Potential Difficulties

  • Changing the focus of police and fire personnel from solely that of handling the incident to reducing the effect of the incident on traffic movement.
  • Achieving cooperation and coordination of agencies across multiple jurisdictions in a region.

Appropriate Measures and Data

Process measures could include the existence of a coordinated system, number of coordination meetings, and number of incidents and events handled properly.

Performance measures oriented to operations could include average trip time, average vehicle delay, vehicle-hours of delay, average speed, and density. Other types of measures can include the number of road users experiencing changed operational conditions, the number of persons taking advantage of travel information, and accuracy and timeliness of traveler information. Ultimately, the performance measure sought for this strategy is the change in crashes involving aggressive driving. A surrogate using changes in aggressive driving may also be considered.

The difficulty of measuring performance is complicated by the fact that analysis of operations and crashes should not be limited to the site or the roads directly affected by an incident. Alternative routes and corridors should also be measured.

Associated Needs

The media play a crucial role in information dissemination. Special public information and education campaigns may be appropriate supplements to an improvement program. Ultimately, dedicated travel-information data sites may be needed.

Organizational, Institutional, and Policy Issues

The introduction of freeway patrols and multiagency traffic-operations committees are two changes in organizational thinking that have facilitated implementing programs for reduction in elements leading to aggressive driving. Freeway service patrols, publicly and privately operated, are being embraced by an increasing number of agencies because their work has been shown to have a high benefits-to-cost ratio.

The Traffic Incident Management Enhancement (TIME) Committee serving southeastern Wisconsin is an example of an organization comprising multiple agencies concerned with traffic operations and safety,

Providing accurate incident information requires that public safety agencies be able and willing to share such data. The data include what happened and an estimation of how long the event will affect travel.

Issues Affecting Implementation Time

  • Changing the focus of incident responders.
  • Training personnel.
  • More advanced systems may require installation and testing of communications infrastructure.


Most of the efforts involve few if any costs, unless new communications infrastructure is required. Photogrammetry for crash sites, which could speed crash investigation, requires purchase of cameras and software. Providing a Web site for traffic information is expensive but usually can be underwritten, in part, with federal or state funds.

Training and Other Personnel Needs

Training is also needed on appropriate reporting of incidents, both for the call takers and by public safety personnel. Better training is also needed in handling traffic as part of incident management.

Legislative Needs

“Must Move” legislation may be considered. It requires motorists involved in minor crashes to move their vehicles off the roadway before calling the police. In addition, liability protection must be extended to public safety agencies to relieve them of tort liability for moving, or directing movement of, vehicles and debris from the roadway.


Key References

AAA Foundation for Traffic Safety. Aggressive Driving: Three Studies. Washington, D.C., 1997. Campbell, B. J. “Speed Compliance During Operation CARE.” Highway Safety Highlights. Vol. 12, No. 4, November 1978.

Connell, Dominic, and Matthew Joint. “Driver Aggression.” Aggressive Driving: Three Studies. AAA Foundation for Traffic Safety, Washington, D.C., 1997.

Dart, Olin K., Jr., and William W. Hunter. “Evaluation of the Halo Effect in Speed Detection and Enforcement.” Transportation Research Record 609. Transportation Research Board of the National Academies, Washington, D.C., 1976, pp. 31–33.

Deffenbacher, J. L., E. R. Lynch, and R. S. Oetting. “Development of a Driver Anger Scale.” Psychological Reports. Vol. 74, 1994, pp. 83–91.

Federal Highway Administration. Freeway Incident Management Handbook. U.S. Department of Transportation, Washington, D.C., 1991.

Hauber, Albert R. “The Social Psychology of Driving Behaviour and the Traffic Environment: Research on Aggressive Behaviour in Traffic.” International Review of Applied Psychology. Vol. 29, No. 4, 1980, pp. 461–74.

Institute of Transportation Engineers. A Toolbox for Alleviating Traffic Congestion and Enhancing Mobility. Ed. Michael D. Meyer, Washington, D.C., 1997.

Kenrick, Douglas T., and Steven MacFarlane. “Ambient Temperature and Horn Honking: A Field Study of the Heat/Aggression Relationship.” Environment and Behavior. Vol. 18, No. 2, 1986, pp. 171–191.

Mannering, Fred, Mark Hallenbeck, and Jodi Koehne. A Framework for Developing Incident Management Systems: A Summary. Washington State Transportation Center, Seattle, Washington, 1992.

McDonald, Peter J., and Scott A. Wooten. “The Influence of Incompatible Responses on the Reduction of Aggression: An Alternative Explanation.” Journal of Social Psychology. Vol. 128, No. 3, 1988, pp. 401–406.

National Highway Traffic Safety Administration. Aggressive Driving and the Law, a Symposium. May 1999.

National Highway Traffic Safety Administration. Implementing a Standard Enforcement Seat Belt Law in Your State: A How-To Guide. DOT HS 809 291, U.S. Department of Transportation, Washington D.C., June 2001.

Novaco, Raymond W. “Automobile Driving and Aggressive Behavior.” The Car and the City. Eds. Martin Wachs and Margaret Crawford, Michigan University Press, Ann Arbor, Michigan, 1992, pp. 234–50.

Raub, R. A., and J. L. Schofer. “Managing Incidents on Arterial Roadways.” Transportation Research Record 1603. Transportation Research Board of the National Academies, Washington, D.C., 1997.

Shinar, David. “Aggressive Driving: The Contribution of the Drivers and Situation.” Transportation Research, Part F. Vol. 1, No. 2, 1998, pp. 137–60.

Smith, Michael F. “Evaluation of Selective Traffic Enforcement Programs for Occupant Restraints.” Research Notes. National Highway Traffic Safety Administration, September 1987.

Surface Transportation Policy Project. Aggressive Driving: Are You at Risk?, April 1999.

Verschuur, William L. G. “The Effects of Police Enforcement and Publicity on Drinking and Driving Behaviour.” Alcohol, Drugs, and Traffic Safety 92. (1223-1227) H. D. Utzelmann, G. Berghaus, eds. Cologne, Germany: Verlag TUV Rheinland, 1993.

Wark, Richard I. “The Motive Vocabulary of Dangerous Driving.” International Conference on Traffic and Transportation Psychology; Berne, Switzerland, 2000.

Wark, Richard I., Roy E. Lucke, and Richard A. Raub. Toward Developing Strategies to Control Aggressive Driving: An Introduction. Northwestern University Center for Public Safety, June 2002.