Paper | 2018

AM18 Poster Hitesh Chawla

  • Authored by:  Hitesh Chawla
  • Co-authored by:  Peter T. Savolainen

Crash Risk and Access Spacing on Two-Lane and Multi-Lane Highways

Hitesh Chawla; Peter T. Savolainen, Ph.D., P.E.


Effective access management is essential to mitigating traffic crash risks. Most of the crashes occurring near access points are a result of conflicts between multiple vehicles. This motivates the development of guidelines for access spacing. To this end, this study evaluated the relationship between crash risk and access point spacing on two-lane and multi-lane highways across the state of Iowa.


As part of the study, data were obtained for 1,247 miles of multi-lane highways and 5,795 miles of two-lane highways.

Several geometric and cross sectional characteristics were taken from Geographical Information Management System (GIMS).

Crash data were acquired for a 5-year period from 2012 through 2016.

Only non-animal crashes were considered for the study.


Based on the models provided within the analysis, it is seen that the access point spacing has a significant effect on crash rate.

Crash rates were found to be more sensitive to access spacing on multi-lane highways as compared to two-lane highways.

In addition to spacing, access volumes were a primary determinant of crash risk, as was the median type for multi-lane highways.

Access Spacing
ACCESS SPACING, AM18, Poster, Student