HD53 - Tables of Speed and Stopping Distances Contained in § 46.2-880 of the Code of Virginia
Executive Summary: During the 2000 session of the Virginia General Assembly, Delegate R. Creigh Deeds introduced House Joint Resolution No. 74 (HJR 74) requesting that the Virginia Transportation Research Council (VTRC) study the table of speed and stopping distances specified in § 46.2-880 of the Code of Virginia. This table notes the total stopping distances of automobiles and trucks -- defined as the sum of the distance the vehicle traveled during the average driver reaction time of 3/4 second and the average distance the vehicle traveled during braking -- at various speeds between 10 mph and 100 mph. The section of the Code also states that all courts shall take notice of the table and shall further take notice that the table was the result of experiments subject to particular conditions. HJR 74 stated that the study shall consider, but not necessarily be limited to, three issues: 1. the accuracy, completeness, and currency of the data specified in the table 2. the amendments to the table that appear to be necessary or desirable 3. the usefulness and appropriateness of continuing to include such a table in the Code of Virginia. The resolution was not reported by the House Committee on Rules. However, the Speaker of the House, S. Vance Wilkins, Jr., requested in a letter that the Acting Assistant Commissioner for Research & Technology of the Virginia Department of Transportation, Dr. Gary R. Allen, consider the issues raised in the resolution and determine whether a review of the table was appropriate. Dr. Allen determined that such a review was appropriate and scheduled the study in the VTRC program. Methodology of the Study The study was separated into three tasks: (1) to investigate the legal issues related to addressing the issues contained in HJR 74, (2) to investigate the scientific issues related to the table specified in the Code, and (3) to determine any necessary amendments to Virginia's table. Legal Issues The first legal issue was to determine the source of the information contained in Virginia's table. The authors searched for references to any studies that would support the numbers cited in Virginia's table and searched the codes of other states to determine the source of this information. The second legal issue involved determining whether other states had similar tables in their codes. This search included a search of the statutes and administrative codes of all 49 other states. The third legal issue related to the ways such tables have been used in Virginia and other states. Virginia case law relating to the use of the table was reviewed, as was the case law of other states. In addition, an informal sample of attorneys, judges, enforcement officials, and transportation engineers were surveyed to determine how they have used the tables. Scientific Issues The scientific literature was examined to determine whether the 3/4-second reaction time listed in the table is appropriate and whether the braking distances listed for automobiles and trucks are accurate. Determination of Necessary Revisions The legal and scientific analyses were synthesized to determine whether any revisions to the table were necessary and whether the table should remain in the Code. Findings The legal analysis did not uncover the source data for the numbers in Virginia's table. The experiments that yielded the numbers are not cited or referred to anywhere else in the Code. Studies conducted prior to the addition of the table to the Code in 1956 did not reveal numbers similar to those listed in the table. The study found that 10 states have related tables in their state codes, but that the tables refer to minimum braking performance requirements and not to average braking or stopping distances. Thus, Virginia is the only state that has a speed and stopping distance table in its code. However, other states have used speed and stopping distance tables in the courtroom, even though no such tables are provided in their statutes. The judicial notice requirement included in Virginia's statute gives the table significant weight in the courtroom, since judges usually apply it without questioning its accuracy or insisting upon further evidentiary proof. Courts have used the tables, usually in actions involving automobile accidents, to absolve a party from charges of negligent driving or, in rare cases, to prove negligence. However, the table is questionable on scientific grounds. The stopping distances listed in the table are at odds with the current state of knowledge. Although the table accounts for a driver's reaction time of 3/4 second, it does not allow for perception time. The scientific and accident reconstruction literature agrees that both perception and reaction time should be taken into account when estimating the total stopping distance of a vehicle at varying speeds. Thus, the table in § 46.2-880 does not allow for adequate perception-reaction time, resulting in a shorter than expected total stopping distance in the Code. Thus, based on the table, a court may conclude that a driver was speeding, even if he or she was not. On the other hand, the table does not account for a half-century of improvements to tires, brakes, and roadways. The braking distances listed in § 46.2-880 are overly generous given the state of today's technology. Thus, based on the table, a court may conclude that a driver was not speeding, even if he or she was. Although the inaccuracies in the table offset one another somewhat, the authors conclude that the table should be updated. The recommended updated table is listed in Appendix C. Table ES-1 compares the numbers in the current table with the numbers recommended by the authors. In essence, Table ES-1 reflects longer distances traveled in perception-reaction time and shorter braking distances. The revisions have the net effect of lengthening the estimated total stopping distance for a given speed. Conclusions • The source of the table in § 46.2-880 remains a mystery. • Information provided in a table of speed and stopping distances can be useful to judges and juries in deciding a case. • The table of speed and stopping distances should be either updated to reflect current technological trends or deleted from the Code. • Updating the table in § 46.2-880 should not present any new problems to the Virginia judicial system; rather, it will help jurors acquire a realistic understanding of stopping distances. • The reaction time of 3/4 second accounted for in § 46.2-880 does not incorporate the factor of perception time that is relevant to total stopping distance. Allowing for perception time would double the estimate of total distance traveled before braking. • The numbers for the braking distances used in the table in § 46.2-880 are too high. These numbers were calculated without consideration of such factors as improved road surface conditions, improved tires, and increasingly sophisticated braking systems. Recommendations I. The speed and stopping distance table in § 46.2-880 should be updated as described in this study rather than deleted. 2. The revised table should be used solely for illustrative purposes or within judicially recognized limits. |
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