About | HeinOnline Law Journal Library | HeinOnline Law Journal Library | HeinOnline
LOG IN
LOG IN

82 Police J. 247 (2009)
Distance Estimation Error in a Roadway Setting

handle is hein.journals/policejl82 and id is 253 raw text is: MARK STRAUSS Ruhl Forensic, Inc., and University of Illinois at Urbana- Champaign, Urbana, Illinois, USA JAMES CARNAHAN University of Illinois at Urbana-Champaign, Urbana, Illinois, USA DISTANCE ESTIMATION ERROR IN A ROADWAY SETTING The purpose of this study was to determine the accuracy of the typical adult's ability to view, then estimate, distances along a roadway. A survey was conducted along a roadway, where 123 subjects were asked to look at, and then estimate the distance to common objects along the roadway. The entire population tended to underestimate distances to objects that were from 20 to 400 feet away. After none outliers were identified and removed, the average estimation error was -23.4%. The vari- ation in performance among individuals was extremely large, with error extremes ranging from -96% to +71%. An analysis of the percentage error in estimation revealed that police performed as well as the rest of the population. The age of the subjects and their rating of their own vision acuity made no statistically significant difference in their average estimation error. Males had significantly lower estimation error than females, as did subjects who rated themselves highly with respect to their distance estimation ability. Keywords: distance; distance estimation error; gender dif- ferences; observer accuracy; witness reliability Introduction Inaccuracies in statements and testimony can be attributed to human error in estimation of distances. Such estimations may be requested of accident witnesses in situations dealing with vehicles and roadways. The purpose of this study was to deter- mine the accuracy of the average adult's ability to view and then estimate distances. A statistical analysis of the estimation accur- acy for different sub-populations of the subjects (police, age, gender, etc.) was performed. The data provide insight regarding the reliability of stated estimated distances and provide averages for quantifying the expected margins of error when estimations are given. Of the participants surveyed, there were 77 males and 46 females, ranging from 18 to 73 years of age. Subjects were of differing educational backgrounds and occupations, including The Police Journal, Volume 82 (2009) 247 DOI: 10.1358/pojo.2009.82.3.458

What Is HeinOnline?

HeinOnline is a subscription-based resource containing thousands of academic and legal journals from inception; complete coverage of government documents such as U.S. Statutes at Large, U.S. Code, Federal Register, Code of Federal Regulations, U.S. Reports, and much more. Documents are image-based, fully searchable PDFs with the authority of print combined with the accessibility of a user-friendly and powerful database. For more information, request a quote or trial for your organization below.



Short-term subscription options include 24 hours, 48 hours, or 1 week to HeinOnline.

Purchase Access

Contact us for annual subscription options:

Contact Us

Already a HeinOnline Subscriber?

Log In

profiles profiles most