Donald A. Bosch is the managing partner in the firm of Bosch & Lusk, P.C., Knoxville, TN. His practice concentrates on white-collar crime and alcohol and drug offenses at the state and federal levels.
Beverley S. Cornett is an associate in the firm of Bosch & Lusk, P.C., Knoxville, TN. Her practice includes defense and appellate representation of drug and white-collar cases in state and federal court.
Dr. Stephen H. Richards, Ph.D. P.E. is the Director of the Transportaton Center at the University of Tennessee,
Knoxville, TN. Previously, he was an assistant research engineer at the Texas Transportation Institute, Texas A&M
University, College Station, TX.
In a time when state legislatures are creating increasingly burdensome laws regarding DUIs, (i.e. per se statutes, lower breath alcohol scores and the lowering of standards of admissibility of those scores, administrative license revocations, etc.) the DUI/DWI practitioner must remain alert to possible defenses. Quite often, behaviors that are mistaken for intoxication can be explained by consideration of innocent factors.
Many defense lawyers have successfully shown that personal characteristics such as slurred speech or bloodshot eyes can be attributed to speech impediments and severe allergies. Lack of motor skills, which often result in a defendant's failure of field sobriety tests, may instead be indicative of serious orthopedic injuries, balance disorders, or a variety of factors affecting physical dexterity. Scientifically based observations, such as horizontal nystagmus, likewise can be explained by factors other than intoxication.
But what about driving behaviors? This article will explore roadway design and operational elements that can cause and contribute to erratic driving behaviors and vehicular accidents. An informed consideration of these factors can lead to persuasive defenses for driving errors that might otherwise result in a finding of "guilty" against a client charged with Driving Under the Influence.
Road Conditions or Defects as a Source of Reasonable Doubt
Proof of road design defects can become an issue as it relates to two areas: as a basis for the stop leading to the DUI arrest, and as an explanation for driving behaviors or errors otherwise mistaken for driver intoxication.Most practitioners are familiar with the various standards for probable cause and the lesser standards for "investigatory stops" respective to the states in which they practice. It can be said that the standard for justifying "investigatory stops" is growing insurmountably broad. Remembering that the standard necessary to reach probable cause is typically higher than that required for an investigatory stop, Tennessee has established its standard for the latter type of stop in a similar manner to many other states. All that is required is a reasonable suspicion supported by specific and articulated facts.1 However, despite lower thresholds required of law enforcement for stops, several states have held that certain driving behaviors do not meet the requisite levels of probable cause or reasonable suspicion. Examples of such driving behaviors that do not meet these standards have included the following: driver traveling at a slower than usual speed on a roadway2; driver straddling the center line once and for a short distance;3 slow operation of a motor vehicle absent any other erratic driving;4 and police observation of a suspect's car weaving three or four times within its lane.5 All of the examples have been held insufficient grounds for a legal stop where such behaviors can be explained by road and/or vehicle conditions and defects. Therefore, proof that these behaviors are a result of defective road or vehicle conditions, coupled with an appropriate motion, can lead to suppression of evidence, an acquittal, or a compromise of charges filed against your client.
An alternate, and potentially more successful, use of a "road conditions or defects" defense would be to present it adequately to the trier of fact. Factors such as roadway and vehicle defects can be compelling when the jury is faced with the question of "why did the defendant wreck, weave, or display other erratic driving behaviors unless he or she was intoxicated?" Given the burden on the prosecution of proving intoxication beyond a reasonable doubt, explanations for such behaviors can create a doubt in the minds of the trier of fact, whether judge or jury, sufficient to gain an acquittal. The following list of common issues, while not all-encompassing, can be used as a starting point for the defense practitioner to create reasonable doubt.
Lane Width
Highway design and safety standards indicate that the normal width of a travel lane is twelve feet.6 As the width of a lane is decreased due to construction costs, topography, or other factors, the likelihood of accidents increases dramatically. In a Kentucky study, the reported accident rate increased by 44 percent on rural two-lane highways when the lane width was eleven feet compared to twelve feet.7 The same study found that lane widths of ten feet resulted in a 53.5 percent increase in the accident rate. Similar findings were reported for urban streets and freeways/expressways.8 Clearly, reduction in lane width adversely impacts driving safety. And an inference can be drawn that lane width reduction also adversely impacts observed driving behaviors.Reduced lane widths have the greatest impact in head-on, sideswipe, and single vehicle/run-off-the-road accidents. These accident types are the same types that often involve individuals accused of DUIs. In addition, very narrow lane widths of eight to nine feet are sometimes used on congested urban roadways and at signalized intersections to increase capacity (i.e., to "squeeze" in an extra lane or two). Not only do these narrow lane widths increase the likelihood of accidents, they also pose a challenge even for non-impaired motorists to track the lane without occasionally encroaching over the lane boundary line. The observed vehicle movements may appear to be the result of driver impairment when in fact they are predictable errors committed by a reasonably alert, average driver negotiating marginal roadway design elements.
Horizontal Alignment/Superelevation
Many suspected DUI accidents are associated with a single vehicle failing to negotiate a curve in the roadway. Although driver impairment due to DUI may be blamed for the accident, an innocent explanation may be found in what is known as horizontal alignment/superelevation deficiencies. Horizontal alignment simply refers to the combination of curves and tangent sections along a highway. The American Association of State Highway and Transportation Officials (hereafter AASHTO) has adopted detailed standards for the design of horizontal alignment elements to provide a reasonable level of safety for motorists.9 Superelevation simply refers to the banking or sloping of the pavement appropriate for the degree of the curve. Likewise, AASHTO has adopted standards for superelevation. When either set of standards is not met, which is often the case with older or secondary roadways, problems of the type described above can be anticipated. Typical alignment deficiencies may include one, or a combination, of the following:
lack of adequate superelevation in the curve;
introduction of the superelevation or banking over too short of a distance, excessive superelevation for the degree of the curve;
failure to widen the pavement (i.e., increase the lane width) at sharp curve, inadequate spacing between curves;
the use of "broken-back" curves, or some other irregular geometry, in lieu of the "circular'' curves.
Exploring each of these elements, or a combination of these elements, may explain deficiencies in driver performance other than the alleged intoxication.
Low Shoulders
It is recommended that the shoulder, whether paved or not, be flush with the travel lane.10 In cases where the shoulder is excessively low, (i.e., there is an abrupt drop-off at the edge of the travel lanes) a potential for "scrubbing-type" accidents may exist. In a classic scrubbing accident, the driver allows the right wheels of his or her vehicle to drop onto the low shoulder. At this point the driver then attempts to gradually steer back onto the driving surface. The presence of the "vertical lip" of the edge drop-off acts as a retardant to the steering effort and the driver must turn the steering wheel increasingly to the left in order to climb the raised edge. However, from the moment the front wheel climbs back onto the travel lane, the vehicle is in an over-steer condition. Depending on the speed and the steering angle required to climb the vertical lift, the vehicle may veer across the travel lane into head-on traffic or go into a spin before the driver can correct the over-steer condition.Scrubbing accidents are often severe, resulting in serious injuries and death. Such accidents can occur at speeds as low as 30 to 40 mph, and drop-off heights as little as 3-4 inches.11 These accidents can appear to be the result of alcohol/drug impairment when the primary cause of the loss of control is the scrubbing phenomenon.
Sight Distances and Sign Placement
Human response considerations dictate that drivers require a finite amount of time (which translates to distance) in order to respond to critical warnings, traffic signs and signals, and other driving cues. The ITE Traffic Engineering Handbook presents "decision sight distances" for avoidance maneuvers under a variety of conditions ranging from a stop on a rural road to a combined lane change and merger onto an urban freeway.12 Similarly, the Manual on Uniform Traffic Control Devices (hereafter MUTCD) presents guidelines for the desirable placement of signs and other traffic controlling devices for three different conditions:1. Where high levels of judgment are needed;
2. Where a stop is required; and
3. When deceleration to a lower speed is advised.13
Unfortunately, the available sight distances or sign placements are, in some instances, inadequate to accommodate even the reasonably prudent driver. Drivers unfamiliar with an area are especially vulnerable in these situations, as they have no prior experience of the circumstances encountered.
How do drivers respond when sight distances or the placement of traffic control devices are not adequate? Depending on the circumstances, typical responses may include:
rapid lane changes, possibly across several lanes;
slowing down to very slow speeds and otherwise unusual braking patterns;
failure to heed a posted warning and/or advisory speed limit; and
failure to track a lane (observed as weaving).14
These same responses can be mistaken for the actions of an intoxicated driver. In certain cases, however, the primary culprit may be the failure to provide critical information to the motorist in a timely fashion based on speed and distance.
Work Zone Traffic Controls
Construction and maintenance work zones pose special challenges to motorists. First, many of the roadway problems already mentioned are more prevalent in work zones, such as poor alignment, narrow lanes, edge drop-offs, insufficient sight distances, and poor placement of traffic control devices. These problems are compounded by the fact that driver expectancy and prior conditioning to the road are violated by the very nature of a temporary work zone; even drivers who know the neighborhood can be surprised by recent construction.There are other special circumstances common to work zones which deserve mention. First, work zones often require the closing of one or more travel lanes and, subsequently, the merging of traffic into the remaining open lane or lanes. Part VI of the MUTCD presents detailed standards for lane closure tapers and other work zone traffic control features.15 For example, the MUTCD requires a minimum taper length equal to the traffic speed multiplied by the width of the closed lane or lanes (L = S x W). If this minimum distance is not provided, motorists will have difficulty performing the merge maneuver in a safe manner. They may respond by braking radically, veering abruptly out of the closed lane(s), or in certain instances, crashing into the barricades, cones, or other devices closing the restricted lane(s). These erratic driving behaviors may be mistaken for alcohol or drug impairment, when the primary cause is in fact an inadequate taper length.16
Another common work zone feature that can cause even alert drivers to become confused and drive erratically is a major detour or route diversion. Detours, by their very nature, present drivers with unexpected and unfamiliar circumstances. Motorists may respond by erratic braking and cycles of slowing down and speeding up, or they may become preoccupied or disoriented to the extent that they fail to notice otherwise obvious traffic control devices, such as a stop sign or traffic signal. Once again, law enforcement can easily attribute such behavior with driver impairment.
Unfamiliar Vehicles
Motorists driving a totally unfamiliar vehicle may exhibit mannerisms not unlike some DUI-impairment behaviors. An example would be an individual driving an unfamiliar rental car. Although there is little empirical data to document this proposition, there is much anecdotal evidence to support this assertion. Drivers who normally drive vehicles with automatic headlights may not realize that their headlights are off for some time, especially in a well-lit urban setting. Unfamiliar drivers may also have trouble finding the wiper controls, turning on the radio, or adjusting the climate controls. While they are engaged in these activities they may exhibit erratic driving behavior for a time, such as unexplained braking and deceleration or lane weaving. Again, these are behaviors often associated with DUI impairment, but can be explained by driver distraction and unfamiliarity with the vehicle.Use of Cellular Telephones
A fairly recent phenomenon which affects driver behavior and can cause or contribute to traffic accidents is the use of cellular phones while driving. A recent United States Department of Transportation (U.S.D.O.T.) study concluded that having a cellular phone in a vehicle increases the risk of being involved in an accident by 34 percent. A Canadian study investigated 699 accidents in which the drivers had access to a cellular phone, and found an even greater likelihood of accidents due to cellular phone use. In 24 percent of these accidents, the drivers had used the phone within ten minutes preceding the accident. The Canadian researchers concluded that cellular phone use increases the risk of an accident by five times.17 The obvious problem arises when the driver is distracted by the competing activity of using the phone while simultaneously attempting to perform the complicated task of driving. Drivers using cell phones are also known to brake and slow erratically, and/or weave within or among lanes.Vehicle Defects
An entire article can be devoted to vehicle defects and their relationship to driving characteristics of the DUI defendant. However, there are common issues relating to vehicle defects that are not readily apparent to the untrained observer, and that are frequently overlooked by counsel in the preparation of a case.Motorists with defective or inoperative wipers are significantly more accident-prone during rain. It is known that rain and wet roads increase accident risks by 2 to 10 times, according to several research studies.18 This increased risk is due to lower pavement traction (coefficient of friction) and reduced visibility. The visibility problem intensifies significantly with very high rates of rainfall (i.e., in excess of two inches per hour), or even at low rainfall rates, if the vehicle's windshield wipers are defective due to poor maintenance or mechanical failure. To illustrate this point, a study found that the effective visual acuity of a motorist using inoperative/ineffective windshield wipers was reduced to 20/200 with a rainfall rate of only 0.3 inches per hour.19 Therefore, erratic driving behaviors, whether the vehicle's wipers were defective or not, can be persuasively explained by the significant reduction in visibility during rain.
Another vehicle defect, often present but not routinely considered, is the poor alignment of a vehicle's headlights. Such misalignment can significantly reduce visibility and subsequently cause erratic driving behavior. Normally, a vehicle's headlights are aligned to shine slightly downward and to the right. Such alignment prevents the headlights from inadvertently blinding approaching drivers, while providing optimal illumination of travel lanes ahead and traffic control devices along the roadside. When the headlight alignment is substantially altered due to poor maintenance or damage, visibility is significantly impacted. Depending on the extent of misalignment, the driver may have difficulty seeing the roadway curvature ahead, and/or traffic control devices on the roadside, in time to respond appropriately.
A lesser-known vehicle defect which can negatively affect vehicle handling and driver performance is "tire mixing."20 Tire mixing can result from the mixing of radial tires with bias-ply tires, different series radials between the front and rear axles, and different size tires on the same axle. The common result is "mushy" or unresponsive steering at higher speeds and in sharper turns. In some extreme cases, tire mixing can reportedly cause a car to "fishtail." The behaviors that result from tire mixing may be mistaken for those caused by driver impairment.
The Expert
Among other issues addressed in this article, an entire column can be devoted to the qualification of experts and the various standards, nationwide, necessary for the admission of testimony pertaining to the issues as described above. Since most states are controlled by evidentiary rules similar to Federal Rule of Evidence 702, and applied in conjunction with the holdings of either Daubert v. Merrell Dow PharmaceuticaIs,21 or Frye v. United States,22 the DUI practitioner should refer to his or her relevant law and rules in making a determination as to how best to proceed with the admissibility of an expert in these fields.Many of the issues illustrated in this column can be introduced through civil or transportation engineers. These individuals are highly educated in roadway and traffic control design concepts, and can often support these premises through their own research or by the introduction of the established research of others. Also, some law enforcement personnel have received special training in road design and traffic control issues, and may qualify as experts in certain limited situations. Further, an expert in human factors engineering, a specialty area of industrial engineering, can assist defense counsel particularly in the issues of vehicle design-driver interface, and the phenomena that occur with the use of unfamiliar vehicles. Finally, do not discount the use of a mechanical engineer or an automotive technician/repairman to render an opinion regarding the condition of the vehicle and its performance and how they relate to the circumstances surrounding a DUI arrest.
A Valid Defense
With the increasing amount of evidence presented by prosecutors in DUI cases, including accident reconstruction evidence, chemical tests, field sobriety tests, etc., the defense practitioner must zealously combat such evidence with all the tools available. Often a prosecutor will either infer or directly argue that the defendant must have been intoxicated based on his or her driving behaviors. Explanations such as those presented here can provide a valid defense to the trier of fact, which may result in an acquittal for your client.Notes
1. Steven Oberman, DUI: The Crime And Consequences In Tennessee, 32 (1991) (citing State v. Foot, 631 S.W.2d 470-472 (Tenn. Crim. App. 1982); Hughes v. State, 588 S.W.2d 296 (Tenn. 1979); State v. McLennan, 503 S.W.2d 909 (Tem. 1973).2. State v. Brown, 509 N.W.2d 69 (ND. 1993).
3. State v. Caron, 534 A.3d 978 (ME. 1987).
4. State v Wiese 525 N.W.2d 412 (Iowa 1994).
5. United States v. Lyons 7 F.3d 973 (1 Oh Cir. 1993).
6. American Association of State Highway and Transportation Officials (AASHTO), A Policy On Geometric Design of Highways and Streets, Washington, DC., 1990.
7. C.V. Zegeer, R. C. Deen, and J. G. Mayes. The Effect of Lane and Shoulder Widths on Accident Reductions on Rural, Two-Lane Roads, Transportation Research Record 806 Transportation Research Board, Washington, D.C., 1981.
8. Synthesis of Safety Research Related to Traffic Control and Roadway Elements, Volumes I & II Washington,D.C., U.S. Department of Transportation, Federal Highway Administration, 1992.
9. American Association or State Highway and Transportation Officials (AASHTO), A Policy On Geometric Design of Highways and Streets, Washington, DC., 1990.
10. Id.
11. Don L. Ivey, Walter A. Johnson, Eric F. Nordlin and Richard A. Zimmer, The Influence of Road Surface Discontinuities on Safety, Washington, D.C., Transportation Research Board -- National Research Council -- 1984.
12. Institute of Transportation Engineers (ITE), Traffic Engineering Handbook, Englewood Cliffs, New Jersey, Fourth Edition, 1992.
13. U.S. Department of Transportation, Federal Highway Administration, Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD), Washington, D.C., 1988.
14. Institute of Transportation Engineers (ITE), Traffic Engineering Handbook, Englewood Cliffs, New Jersey, Fourth Edition, 1992
15. U.S. Department of Transportation, Federal Highway Administration, Part VI of the Manual on Uniform Traffic Control Devices (MUTCD) Standards and Guides for Traffic Controls for Street and Highway Construction, Maintenance, Utility, and Incident Management Operations, Washington, D.C., 1993, 1988 Edition of MUTCD, Revision 3.
16. Synthesis of Safety Research Related to Traffic Control and Roadway Elements, Volumes I & II Washington, D.C., U.S. Department of Transportation, Federal Highway Administration, 1992.
17. D A. Redelmeier and R. J. Tibshiranilkj, Association Between Cellular Telephone Calls and Motor Vehicle Collisions, New England Journal of Medicine, 336:453-502 (1997).
18. M.R. Parker, Jr., Synthesis of Safety Research Adverse Environmental Conditions, Washington, D.C., U.S Department of Transportation, Federal Highway Administration, 1992.
19. R.S. Morris, J.M. Mounce, J.W. Button, and N.E. Walton, Field Study of Driver Visual Performance During Rainfall, Report No. DOT-HS-5-D1 172, U.S. Department of Transportation, Washington, D.C., 1976.
20. J. Stannard Baker and Lynn B. Fricke, The Traffic-Accident Investigation Manual At Scene Investigation and Technical Follow, Evanston, Illinois, Northwestern University Traffic Institute, 1986.
21. Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993).
22. Frye v. United States, 293 F. 1013 (D.C. Cir. 1923). n
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