Addressing Collisions Involving Unlicensed Drivers and Drivers with Suspended or Revoked Licenses

Executive Summary

The Problem

No matter how well our highways and vehicles are designed and maintained, ultimately highway safety depends upon the behavior of users, especially drivers. Every state has a driver-licensing program that is charged with ensuring that drivers who are issued a license are competent to operate on the roadway system. There are strong pressures on licensing programs to limit imposition, including costs, on renewal applicants. At the same time, licensing agencies have a legal responsibility to the greater public to license only qualified drivers and to keep unqualified drivers off the road.

There are two groups of drivers who continue to drive without proper licensure. First, there is a small number of drivers who appear immune to countermeasures that have proved effective for most highway users. These “hard-core offenders” continue to drive even after losing a license and are overrepresented in subsequent violations and crashes. It is estimated that as many as three-fourths of suspended and revoked (S/R) drivers continue to drive, although they apparently drive less often and more carefully (van Oldenbeek and Coppin, 1965; Hagen et al., 1980; Ross and Gonzales, 1988; DeYoung, 1990). Even so, they are overrepresented in subsequent violations and crashes and, based on estimated exposure, are greatly overrepresented in fatal crashes (DeYoung et al., 1997). In California, based on an analysis of two-vehicle fatal crashes in which only one driver was judged to be at fault, compared with validly licensed drivers, S/R drivers were found to be overinvolved by a factor of 3.7:1.

A second group of drivers is those who have never held proper licensure. In at least some regions of the country, these are often illegal aliens who fear detection if licensure is sought. In the same California study, this driver group is reported to be even more overrepresented in crashes than S/R drivers by a factor of 4.9:1 (DeYoung et al., 1997). The threat of detection and deportation are believed to be a major reason this group avoids seeking licensure, and often their driving provides transportation for other illegal alien workers (DeYoung, personal communication, 2000). Because of the increasing numbers of these workers, as well as the dependence of significant segments of the economy on their labor, this issue is one that cries out for innovative solutions.

A recent report (Griffin and DeLaZerda, 2000) analyzing 5 years of Fatality Analysis Reporting System (FARS) data found that one out of five fatal crashes involves at least one driver who is not properly licensed (unlicensed, S/R, expired, canceled or denied, unknown). Because exposure data were not available, mileage rates of involvement could not be calculated for each category or for validly licensed drivers.

Exhibit I-1 shows the proportion of unlicensed or improperly licensed drivers in fatal crashes for the year 2000, the most recent year for which data are available. Here about 17 percent of drivers in fatal crashes are not properly licensed, a proportion far higher than estimated for all drivers. It should be noted that this table is based on drivers, not on number of crashes.

Proportion of Drivers Not Licensed or Holding No Valid License for this Class of Vehicle, Fatal Crashes, 2000

First Harmful Event in Crash

Unlicensed/No Valid License, Percent





Pedal cycle


Motor vehicle in transport


Parked motor vehicle


Bridge abutment, rail; guardrail; concrete barrier


Sign, post, pole


Culvert, curb, ditch, embankment


Fence, wall


Tree, other fixed object


Involvement in any crash type listed above*


*Not every first harmful event is included, but for all events in original table, 17% of the total drivers were unlicensed or held no valid license for the class of vehicle operated.

Based on the Fatality Analysis Reporting System (FARS) Web-based encyclopedia, available at (Accessed August 12, 2002).

Despite the marked over-involvement of improperly licensed drivers in fatal crashes, traffic violations are often not treated seriously in the court system, where prosecutors and others consider burglaries, assaults, and other crimes of greater import (even though people are at much greater risk of a crash injury than of being the victim of a crime). The use of separate traffic courts that handle only traffic offenses will increase the likelihood of appropriate sanctions.

These unlicensed/suspended/revoked (U/S/R) drivers are especially difficult to reach and to influence. However, there are some interventions that have shown promise and are worthy of further implementation.

The most severe sanctions have been evaluated primarily on the basis of driving-under-the-influence (DUI)1 offenders, not drivers who are S/R for other reasons. However, DUI offenders have proved to be some of the most intractable, so that measures showing impact on this group are likely to be effective with other U/S/R drivers.

Applicable Countermeasures

Exhibit I-2 shows the objectives and strategies identified for keeping U/S/R drivers off the road. Five major objectives are identified.

Objectives and Strategies for Ensuring Drivers Are Fully Licensed and Competent by Keeping Unlicensed Drivers and Drivers with Suspended and Revoked Licenses Off the Road



2.1 A—Apply special enforcement practices

2.1 A1—Increase enforcement in selected areas

2.1 A2—Routinely link citations to driver record

2.1 A3—Create and distribute “hot sheets”

2.1 B—Restrict mobility through license plate modification or removal

2.1 B1—“Stripe” license plate

2.1 B2—Impound license plate

2.1 C—Restrict mobility through vehicle modification

2.1 C1—Immobilize/impound/seize vehicle

2.1 C2—Install ignition interlock device (IID)

2.1 D—Restrict mobility through direct intervention with offender

2.1 D1—Monitor electronically

2.1 D2—Incarcerate

2.1 E—Eliminate need to drive

2.1 E1—Provide alternative transportation service

Explanation of the Objectives

The strategies in this guide were identified from a number of sources, including the literature, contact with state and local agencies throughout the United States, and federal programs. Some of the strategies are widely used, while others are used at a state or even a local level. Some have been subjected to well-designed evaluations to prove their effectiveness. On the other hand, it was found that many strategies, including some that are widely used, have not been adequately evaluated.

The implication of the widely varying experiences with these strategies, as well as the range of knowledge about their effectiveness, is that the reader should be prepared to exercise caution in many cases before adopting a particular strategy for implementation.

Apply special enforcement practices. As can be seen in Exhibit I-2, reducing U/S/R driving can be addressed by a range of strategies. Enforcement is generally part of the intervention, and some interventions can be handled almost entirely by enforcement. These strategies include increasing enforcement in areas with previously detected high rates of improperly licensed drivers (e.g., crashes, high number of committed violations, or in routine license checks); and routine checking of citations against driver license file to identify drivers who have lost licensure but who may still carry a license that appears valid. A third enforcement practice is to create and distribute to law enforcement “hot sheets” that list the U/S/R drivers living in the area.

Restrict mobility through license plate modification. Public identification of the license plate has been achieved through “zebra” striping of the plate, a measure that is readily identifiable by enforcement but is not usually noticed by the public at large. Vehicles displaying these plates alert officers to the possibility of an offending driver, although a validly licensed driver may drive the vehicle. Nevertheless, such striping makes the vehicle more likely to be checked. Another measure shown to be effective is impoundment of the license plate itself.

Restrict mobility of offender through vehicle modification. Restricting mobility by modifying the vehicle can be achieved by immobilizing or impounding the vehicle (and in extreme cases, seizing and disposing of the vehicle), modifying the vehicle with an ignition interlock device (IID) that ensures operation by a sober driver, and modifying the vehicle so that ignition requires a valid electronic drivers license. This latter strategy cannot be widely implemented until there is widespread development of vehicles and systems that are compatible with electronic licenses.

Restrict mobility of offender through direct intervention with the offender. Restricting mobility through direct intervention with the offender can take the form of electronic monitoring (“house arrest”) or incarceration. While the latter has long been used, it has not been shown to be highly effective by itself (although one cannot commit traffic offenses while incarcerated). Still, incarceration remains an important strategy to motivate compliance with other strategies, such as electronic monitoring. Interestingly, electronic monitoring has been used successfully since 1984 in at least one jurisdiction and generates sufficient income to make the program self-supporting. Incarceration, although used, is recommended primarily as an option to ensure compliance with other strategies.

Eliminate the need to drive. In areas where alternative transportation is available, it may be possible to enforce its use. Even if public transit is not readily available, as is the case in most communities, other forms of transportation exist, such as car-pooling, taking a taxi, using a dial-a-ride service, using a hired driver, or using other forms of paratransit. However, it could be difficult to ensure that convicted offenders restrict their mobility to such alternatives. Providing alternative transportation has been shown to be effective in at least one (affluent) community, but it is a potentially expensive strategy. At this time, it is unlikely to be a viable strategy in many communities, but where applicable, it should be seriously considered.

While some of these strategies require legislative authorization and must be implemented at the state level, others can be introduced at a local level by local enforcement agencies. Furthermore, legal authorization often exists for some of the strategies, but in the absence of local interest and commitment, implementation does not occur. For most strategies, whether national, state, or local, ultimately it is at the local level that implementation occurs (or does not occur). In trying to implement a strategy, it is often helpful to develop a coalition of key stakeholders to determine how best to proceed. Such a coalition can not only improve the quality of the program implemented but also generate broad support for the program.

One of the hallmarks of the AASHTO Strategic Highway Safety Plan is to approach safety problems in a comprehensive manner. The range of strategies available in the guides will ultimately cover various aspects of the road user, the highway, the vehicle, the environment, and the management system. The guides strongly encourage the user to develop a program to tackle a particular emphasis area from each of these perspectives in a coordinated manner. To facilitate this program, the electronic form of the material uses hypertext linkages to enable seamless integration of various approaches to a given problem. As more guides are developed for other emphasis areas, the extent and usefulness of this form of implementation will become ever more apparent.

The goal is to move away from independent activities of engineers, law enforcement, educators, judges, and other highway-safety specialists. The implementation process outlined in the guides promotes the formation of working groups and alliances that represent all of the elements of the safety system. In so doing, highway-safety specialists can draw upon their combined expertise to reach the bottom-line goal of reducing crashes and fatalities associated with a particular emphasis area.

1 Some jurisdictions use DWI, for driving while intoxicated, instead, and some states use both DUI and DWI, relating the terms to level of intoxication. In this document, DUI is used, even when a particular state may use DWI. The use of DUI in this report does not imply a particular level of alcohol intoxication.