Analysis and methods of improvement of safety at high-speed rural intersections [technical summary].
Advanced Search
Select up to three search categories and corresponding keywords using the fields to the right. Refer to the Help section for more detailed instructions.

Search our Collections & Repository

All these words:

For very narrow results

This exact word or phrase:

When looking for a specific result

Any of these words:

Best used for discovery & interchangable words

None of these words:

Recommended to be used in conjunction with other fields



Publication Date Range:


Document Data


Document Type:






Clear All

Query Builder

Query box

Clear All

For additional assistance using the Custom Query please check out our Help Page


Analysis and methods of improvement of safety at high-speed rural intersections [technical summary].

Filetype[PDF-600.09 KB]

  • English

  • Details:

    • Corporate Creators:
    • Resource Type:
    • Geographical Coverage:
    • Edition:
      Technical summary.
    • Abstract:
      INTRODUCTION: Since 2006, INDOT has been preparing an annual fivepercent

      report that identifies intersections and segments

      on Indiana state roads that require attention due to the

      excessive number and severity of crashes. Many of the

      identified intersections are two-way, stop-controlled intersections

      located on high-speed, multi-lane, rural roads.

      Some contributing design and human factors have been

      identified, while other factors still await investigation.

      Multivariate ordered probit models have been developed

      to help identify additional factors of the frequency and severity

      of crashes. These models can estimate how much

      different factors increase the frequency of crashes at

      several levels of injury severity (fatal/incapacitating, nonincapacitating/

      possible, and property-damage-only). They

      have a unique ability to account for unobserved but common

      conditions that affect all of the crash severity levels.

      Recommendations for safety countermeasures are made

      based on both of these research results and our study of

      published reports of other authors.

      FINDINGS: The statistical analysis was performed on 553 existing

      intersections in Indiana and 72 existing intersections in

      Michigan using crash data reported during a four-year

      period. The identified safety factors include the following:

      presence of horizontal curves within the intersection vicinity,

      traffic volume on the major road, land use, population

      of the area surrounding the intersection, the minor road

      functional class (traffic volume on minor road unknown),

      nearby at-grade railroad crossings, intersection conspicuity

      to drivers on the major road, acceleration lanes for

      both left and right turns, median width, intersection angle,

      and number of intersection legs. These results are in line

      with other research results as documented in the literature


      Based on the results of this and other studies, recommendations

      are made to improve safety at new intersections

      as well as at existing intersections. For new intersections,

      construction of medians wider than 80 feet is suggested.

      Where this is not possible and a narrower median needs

      to be constructed, adding a parallel acceleration lane for

      vehicles turning left from the minor road is suggested. Intersections

      should be placed at a sufficient distance from

      horizontal curves and from at-grade railroad crossings.

      Solutions with indirect left-turn lanes (Michigan U-turns,

      J-turns) are recommended.

      At existing intersections experiencing excessive numbers

      of crashes involving vehicles from the minor road, median

      closure should be considered or a median opening should

      be restricted to certain maneuvers. Median acceleration

      lanes can be added in order to allow a two-stage maneuver

      for left turns from the minor road. Enhanced guide

      and warning signage can be used to improve intersection

      conspicuity; adding road illumination can especially help

      at night. The practice of adding left- and right-turn bays

      should be continued as this is a proven intersection safety

      improvement practice. Applying these countermeasures

      may help improve safety and avoid the construction of

      expensive grade separations.

      Finally, advanced intersection collision avoidance systems,

      such as road-side dynamic signs warning drivers

      on the minor road about a short gap on the major road,

      should be the subject of pilot studies in Indiana. Experiments

      in other states have indicated that these systems

      help drivers choose safe gaps.

    • Format:
    • Funding:
    • Main Document Checksum:
    • File Type:

    Supporting Files

    • No Additional Files

    More +

    You May Also Like

    Checkout today's featured content at

    Version 3.24