Evaluating the Role of Weaving Section Characteristics and Traffic on Crashes in Weaving Areas

Abstract

Objective: The likelihood of being involved in a crash on a freeway, in general, is greater on weaving sections than on basic freeway sections and in ramp influence areas. This is due to possible crossing of entry and/or exit traffic over a short distance while traveling in the same direction without the aid of traffic control devices resulting in potential conflicting situations and crashes. This article focuses on evaluating the role of weaving section characteristics (configuration type, length and the number of required lane changes by weaving traffic) and traffic variables (entry volume, exit volume, and non-weaving volume) on crashes in weaving areas.

Methods: Data collected for 25 weaving sections in the Las Vegas metropolitan area are used to study the relationship between crashes and weaving section characteristics and traffic variables. The relationship between (1) crashes by selected collision types and contributing factors and (2) weaving section characteristics and traffic variables are also examined. Descriptive and statistical analysis techniques were used.

Results: The number of crashes tends to decrease with increase in length of weaving section. Increase in entry volume increases crashes due to improper lane change and ran off roadway crashes. On the other hand, increase in exit volume increases rear-end crashes, crashes due to following too closely, and crashes due to inattentive driving. Non-weaving volume, in general, also appears to play a prominent role in explaining most crash types and contributing factors on weaving sections.

Conclusions: Type “A” weaving section tends to be relatively safer when compared to other weaving configuration section types. Retrofitting weaving sections with short lengths or designing sections with longer lengths, in addition to increased use of in-vehicle warning systems, may reduce crashes and improve safety. Ramp metering, enforcement, changeable message signs (speed signs), and capacity improvements are other solutions for consideration.

Keywords:

• Crashes
• Weaving section
• Configuration
• Traffic
• Freeway
• Statistical analysis

ACKNOWLEDGEMENTS

The authors acknowledge the Nevada Department of Transportation (NDOT) for their help with crash database and traffic reports.

Notes

∗2, 5, and 7 indicate crash collision types; 3, 4, 6, and 8 indicate crash contributing factors.

∗∗Indicate crashes per total number of required lane changes by weaving traffic (example, total crashes indicate total crashes per total number of required lane changes by weaving traffic).

∗∗∗S is standard deviation of the error term.

∗∗∗∗Length of weaving section is expressed in feet; Note that 1 mile = 1.6 kilometers = 5,280 feet.